milewski's Journal

@beartracker @maxallen @aguilita @jwidness @matthewinabinett @davidbygott @ptexis @taogirl

INTRODUCTION

The pronghorn (Antilocapra americana) is renowned for its extreme speed and endurance when galloping - a topic which I do not address in this Post.

Instead, my aim is to illustrate the following, lesser-known gaits of the pronghorn, viz.

• walking, and
• various 'display gaits', the function of which is partly to signal individual fitness to predators and/or conspecifics.

The gaits of the pronghorn have been well-documented for more than 40 years (Bullock 1982, https://d1wqtxts1xzle7.cloudfront.net/38898576/Franklin_Vicuna_1974.pdf?1443280555=&response-content-disposition=inline%3B+filename%3DThe_Social_Behavior_of_the_Vicuna_p_477.pdf&Expires=1712873946&Signature=SECkGoREl0a4cUhkekReWb~lmpS6pcXk3a8mKqpPS1NBzaognfNWVSikWAgOp8og4Zg5hKKo7IwBdCpRhQJoFctQfmEmTybFmoOLzO4mw5I6veY5WEbKvheRW6Fs1KwCuTXl-7JONfeN1~hknoodkwwpFlnCA4Jx7k6Z6UzoL~T3CSTtUAgdBOhfXJBPHUTLzjELAzBrYbmWIsfTh3LCiJAjQyeqerYW32CUzD7OQs4nUk-yyMG028rFb-yvfhlYljCstpqVvzsPMc1ppUe1xlbg4xrtVh59t1-H7XDKRYeu-CXvagQt-pDu7aMuBrsYKaQXR0qcAwCElwV6b4jVbg__&Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA#page=272 and https://cdnsciencepub.com/doi/abs/10.1139/z82-243?journalCode=cjz and https://www.researchgate.net/publication/237992215_An_analysis_of_locomotor_body_movements_in_pronghorn_antelope and https://cdnsciencepub.com/doi/abs/10.1139/z82-243 and https://www.jstor.org/stable/3830497).

However, it is only now that there are enough photos of this species on the Web to illustrate certain gaits clearly. The terms I use do not necessarily correspond to those of Bullock (1982).

RESULTS

Cross-walking:

https://medium.com/usfws/rare-sonoran-pronghorn-are-rebounding-5de9c5343ded

https://www.inaturalist.org/observations/151154169

https://www.inaturalist.org/observations/111103776

https://www.inaturalist.org/observations/192148380

https://www.inaturalist.org/observations/7877948

https://www.inaturalist.org/observations/45872075

https://www.inaturalist.org/observations/45933776

https://www.inaturalist.org/observations/22592549

https://www.inaturalist.org/observations/198888097

https://www.inaturalist.org/observations/67474435

https://www.inaturalist.org/observations/60448113

https://www.inaturalist.org/observations/49918376

https://www.inaturalist.org/observations/14608967

https://www.inaturalist.org/observations/206380030

https://www.inaturalist.org/observations/188952650

https://www.inaturalist.org/observations/136027864

https://www.inaturalist.org/observations/120592993

https://www.inaturalist.org/observations/117610955

https://www.inaturalist.org/observations/112181226

https://www.inaturalist.org/observations/105114626

https://www.inaturalist.org/observations/34874373

https://www.inaturalist.org/observations/27069190

https://www.inaturalist.org/observations/646613

https://www.inaturalist.org/observations/172730233

https://www.inaturalist.org/observations/160784537

https://www.inaturalist.org/observations/86366821

https://www.inaturalist.org/observations/69182943

https://www.inaturalist.org/observations/126642775

https://www.inaturalist.org/observations/168931232

https://www.inaturalist.org/observations/149564088

https://www.inaturalist.org/observations/104441773

https://www.inaturalist.org/observations/72881424

https://www.inaturalist.org/observations/28156962

https://www.inaturalist.org/observations/194604847

https://www.inaturalist.org/observations/189136437

https://www.inaturalist.org/observations/188672871

https://www.inaturalist.org/observations/169802309

https://www.inaturalist.org/observations/169102077

https://www.inaturalist.org/observations/164225148

https://www.inaturalist.org/observations/141591681

https://www.inaturalist.org/observations/128406785

https://www.inaturalist.org/observations/58704010

https://www.inaturalist.org/observations/25524800

https://www.inaturalist.org/observations/369882

https://www.inaturalist.org/observations/198029380

https://www.inaturalist.org/observations/83973812

https://www.inaturalist.org/observations/38435151

https://www.inaturalist.org/observations/19730539

https://www.inaturalist.org/observations/81736547

https://www.inaturalist.org/observations/18340076

https://www.inaturalist.org/observations/13011401

https://www.inaturalist.org/observations/10091257

https://www.inaturalist.org/observations/180569759

https://www.inaturalist.org/observations/162597053

https://www.inaturalist.org/observations/112784916

https://www.inaturalist.org/observations/206481220

https://www.inaturalist.org/observations/167297136

https://www.inaturalist.org/observations/144115273

https://www.inaturalist.org/observations/124978685

https://www.inaturalist.org/observations/202996237

Semi cross-walking:

https://www.storyblocks.com/video/stock/pronghorn-antelope-walking-in-the-plains-hag1g3ixwj2v2c9nu

https://stock.adobe.com/video/pronghorn-antelope-walking-in-the-plains/191515413?as_campaign=ftmigration2&as_channel=dpcft&as_campclass=brand&as_source=ft_web&as_camptype=acquisition&as_audience=users&as_content=closure_asset-detail-page

https://www.storyblocks.com/video/stock/pronghorn-antelope-tracked-while-walking-in-grass-ki1bmav

https://www.inaturalist.org/observations/169977981

https://www.inaturalist.org/observations/81226031

https://www.inaturalist.org/observations/165599558

https://www.inaturalist.org/observations/77144531

https://www.inaturalist.org/observations/108666122

https://www.inaturalist.org/observations/4682916

https://www.inaturalist.org/observations/180187343

https://www.inaturalist.org/observations/141759202

https://www.inaturalist.org/observations/116033559

https://www.inaturalist.org/observations/95166793

https://www.inaturalist.org/observations/190532708

https://www.inaturalist.org/observations/187425583

https://www.inaturalist.org/observations/187403044

https://www.inaturalist.org/observations/164915852

https://www.inaturalist.org/observations/161660531

https://www.inaturalist.org/observations/120618226

https://www.inaturalist.org/observations/112788711

https://www.inaturalist.org/observations/45924357

https://www.inaturalist.org/observations/37510543

https://www.inaturalist.org/observations/7975933

https://www.inaturalist.org/observations/173803819

https://www.inaturalist.org/observations/192932980

https://www.inaturalist.org/observations/24766943

https://www.inaturalist.org/observations/2313666

https://www.inaturalist.org/observations/202605521

https://www.inaturalist.org/observations/105126822

https://www.inaturalist.org/observations/16640889

https://www.inaturalist.org/observations/181843893 and https://www.inaturalist.org/observations/179269836

https://www.inaturalist.org/observations/181284223

https://www.inaturalist.org/observations/176878956

https://www.inaturalist.org/observations/172456278

https://www.inaturalist.org/observations/138443166

https://www.inaturalist.org/observations/135297540

https://www.inaturalist.org/observations/130235159

https://www.inaturalist.org/observations/123661093

https://www.inaturalist.org/observations/92061482

https://www.inaturalist.org/observations/90601957

https://www.inaturalist.org/observations/27175238

https://www.inaturalist.org/observations/25857516

https://www.inaturalist.org/observations/19058413

https://www.inaturalist.org/observations/12998710

https://www.inaturalist.org/observations/199628

https://www.inaturalist.org/observations/159245812

https://www.inaturalist.org/observations/192495811

https://www.inaturalist.org/observations/173367219

https://www.inaturalist.org/observations/124848728

https://www.inaturalist.org/observations/124652556

https://www.inaturalist.org/observations/105552317

https://www.inaturalist.org/observations/90042028

https://www.inaturalist.org/observations/77808716

https://www.inaturalist.org/observations/71174311

https://www.inaturalist.org/observations/66697932

https://www.inaturalist.org/observations/19299335

https://www.inaturalist.org/observations/1434006

https://www.inaturalist.org/observations/192755246

https://www.inaturalist.org/observations/184207314

https://www.inaturalist.org/observations/181446232

https://www.inaturalist.org/observations/170446653

https://www.inaturalist.org/observations/168856780

https://www.inaturalist.org/observations/153092774

https://www.inaturalist.org/observations/123618854

https://www.inaturalist.org/observations/116494036

https://www.inaturalist.org/observations/71882182

https://www.inaturalist.org/observations/62759588

https://www.inaturalist.org/observations/57729297

https://www.inaturalist.org/observations/39740119

https://www.inaturalist.org/observations/8697208

https://www.inaturalist.org/observations/178173951

https://www.inaturalist.org/observations/165313189

https://www.inaturalist.org/observations/40796530

https://www.inaturalist.org/observations/5173255

https://www.inaturalist.org/observations/200516676

https://www.inaturalist.org/observations/131997891

https://www.inaturalist.org/observations/128984894

https://www.inaturalist.org/observations/128984893

https://www.inaturalist.org/observations/108361908

https://www.inaturalist.org/observations/60921261

https://www.inaturalist.org/observations/28039844

https://www.inaturalist.org/observations/6186244

https://www.inaturalist.org/observations/171266598

https://www.inaturalist.org/observations/125877305

https://www.inaturalist.org/observations/116925430

https://www.inaturalist.org/observations/104078696

https://www.inaturalist.org/observations/62604018

https://www.inaturalist.org/observations/38034079

Ambling:

https://www.shutterstock.com/da/video/clip-1093543127-pronghorn-antelope-walking-through-utah-desert-during

https://blog.gritrsports.com/big-game-profile-pronghorn/

https://www.oceanlight.com/spotlight.php?img=19627

https://www.inaturalist.org/observations/74202062

https://www.inaturalist.org/observations/172746714

https://www.inaturalist.org/observations/41200343

https://www.inaturalist.org/observations/60531788

https://www.inaturalist.org/observations/5119706

https://www.inaturalist.org/observations/38203216

https://www.inaturalist.org/observations/89398530

https://www.inaturalist.org/observations/26399635

https://www.inaturalist.org/observations/161080559

https://www.inaturalist.org/observations/137670731

https://www.inaturalist.org/observations/197367318

https://www.inaturalist.org/observations/137336427

https://www.inaturalist.org/observations/193225312

https://www.inaturalist.org/observations/153326755

https://www.inaturalist.org/observations/14970879

https://www.inaturalist.org/observations/160981894

https://www.inaturalist.org/observations/143827822

https://www.inaturalist.org/observations/165313190

https://www.inaturalist.org/observations/143377354

https://www.alamy.com/video/pronghorn-walking-in-a-field-582837040.html

https://www.inaturalist.org/observations/75666276

Proud-trotting:

https://www.inaturalist.org/observations/162332610

https://www.inaturalist.org/observations/6506049

https://www.inaturalist.org/observations/119916340

https://www.inaturalist.org/observations/28842659

https://www.inaturalist.org/observations/10151399

https://www.inaturalist.org/observations/196884072

https://www.inaturalist.org/observations/153327177

https://www.inaturalist.org/observations/142944555

https://www.inaturalist.org/observations/65214769

https://www.youtube.com/watch?v=58bODe6e7gA

Stotting:

https://blissphotographics.com/pronking-pronghorn-levitating/

https://blissphotographics.com/pronghorn-levitation-stotting-or-pronking/

https://www.pinterest.com.au/pin/graceful-pronghorn-in-midair--320529698481685013/

https://www.inaturalist.org/observations/99162488

https://www.inaturalist.org/observations/26690567

https://www.inaturalist.org/observations/153327177

https://www.inaturalist.org/observations/20058575

https://www.inaturalist.org/observations/81342377

https://www.inaturalist.org/observations/18212065

https://www.inaturalist.org/observations/5028581

https://www.alamy.com/stock-photo-pronghorn-antelope-antilocapra-americana-fawn-running-in-grassland-26797480.html

DISCUSSION

The pronghorn conforms to a category of ungulates that I have called 'plains game'.

This is because it combines the following features/traits:

• exposed habitat, lacking cover,
• gregariousness,
• cursoriality and migration (https://www.youtube.com/watch?app=desktop&v=ig2VR6aAu4M),
• lateral placement of the eyes (https://www.inaturalist.org/observations/86028387 and https://www.inaturalist.org/observations/20720325 and https://www.youtube.com/watch?v=j5QQ85aXipc and https://www.inaturalist.org/observations/123766827 and https://www.inaturalist.org/observations/79483159),
• conspicuous colouration, even at distance (https://www.inaturalist.org/observations/67782104 and https://www.inaturalist.org/observations/70291649 and https://www.inaturalist.org/observations/116295944 and https://www.inaturalist.org/observations/9807652 and https://www.inaturalist.org/observations/197435261 and https://www.inaturalist.org/observations/33663443 and https://www.inaturalist.org/observations/2678702 and https://www.inaturalist.org/observations/53522820),
• minor sexual dimorphism (https://www.inaturalist.org/observations/144092409 and https://www.inaturalist.org/observations/128676306 and https://www.inaturalist.org/observations/187659485 and https://www.inaturalist.org/observations/138672584 and https://www.inaturalist.org/observations/146685807),
• reluctance to jump over fences (https://tpwd.texas.gov/publications/pwdpubs/media/pwd_lf_w7000_1787.pdf and https://www.facebook.com/watch/?v=854823252123488 and https://www.greatfallstribune.com/videos/news/2017/05/05/watch-pronghorn-crawling-underneath-fences/101298706/ and https://www.youtube.com/watch?v=hnVHZBin5x4 and https://www.youtube.com/watch?v=XyvfiNDtiAI and https://www.inaturalist.org/observations/115502513 and https://www.youtube.com/watch?v=VyVwSi4A6ps and https://www.youtube.com/watch?v=aJMTc8wqDl0), and
• seasonal reproduction.

Species of 'plains game' in the family Bovidae, in Africa and Eurasia, typically amble. I refer to all Alcelaphini and Hippotagini, and certain Antilopini, Reduncini, and possibly Caprini.

Based on its evolutionary convergences with 'plains game', we would expect the pronghorn to amble.

However, Bullock (1982) - despite the thoroughness of his study - did not find the pronghorn to amble.

So, is it true that the pronghorn is anomalous relative to bovid 'plains game', in lacking an ambling gait?

My study, as illustrated in this Post, offers a correction to Bullock (1982). In fact, the pronghorn does sometimes amble.

The pronghorn is partly aligned with Cervidae, a family in which ambling is absent in even those species

• most resembling 'plains game', e.g. Cervus canadensis, and
• with the most lateral placement of the eyes, e.g. Dama dama.

The following (https://www.youtube.com/watch?v=V8-1p8WhAYo and https://www.youtube.com/watch?v=r72AnyDaxS0) show the cross-walk typical of Cervidae.

On this basis, it would seem that the pronghorn incongruously combines cross-walking with extreme speed and endurance of galloping.

The diagnostic pattern of 'diagonal' walking gaits - including the cross-walk of the pronghorn - is that the hind foot lifts only once the contralateral foot lands, and the hind foot lands approximately in the track of the ipsilateral fore foot (https://www.inaturalist.org/observations/40017869 and https://www.inaturalist.org/observations/65114417 and https://www.inaturalist.org/observations/204861686 and https://www.inaturalist.org/observations/167405274 and https://www.inaturalist.org/observations/18491683).

Bullock (1982) documented that the pronghorn varies this in two ways, viz.

• the hind foot lifts only once the contralateral fore foot lands (= what I term 'nearly ambling'), and/or
• the hind foot lands slightly anterior to the track of the ipsilateral fore foot (possibly shown in https://www.inaturalist.org/observations/775048).

However, Bullock (1982) failed to document the full versatility of walking gaits in the pronghorn.

The following (https://www.inaturalist.org/observations/126912485) shows this versatility. The juvenile individual on the left is cross-walking, while that on the right is ambling.

In the case of 'display gaits', there is also something new to be investigated about the pronghorn. This is the possibility of two 'display gaits' additional to stotting (in the narrow sense).

These are

• exaggerated cross-walking (resembling that in cervids e.g. Odocoileus, https://www.sierraclub.org/sierra/assisted-migration-helps-animals-adapt-climate-change), and
• exaggerated trotting (= proud-trotting, resembling that in bovids e.g. Alcelaphus).

However, I have found few unambivalent illustrations of stotting/display gaits in the pronghorn, in either the strict or the loose sense. According to Bullock (1982), stotting is mainly an intraspecific (as opposed to anti-predator) display in the pronghorn, and observed mainly in the breeding season. However, this remains poorly documented photographically.

It is remarkable that infants seem not to stot during play behaviour (https://www.youtube.com/watch?v=ZwE_IFvABKw and https://www.youtube.com/watch?v=NQdzJm0A5co).

The pronghorn is extreme, among ungulates, in advertising itself by means of piloerection of the white bleeze on the hindquarters (https://www.inaturalist.org/observations/17052354 and https://www.inaturalist.org/observations/144032230 and https://www.inaturalist.org/observations/124828985).

However, any correlation between gait and the piloerection of this acetabulo-ischiopygal bleeze - which often occurs when the figure is stationary - is weak.

MAIN QUESTIONS RAISED

This investigation has raised three main questions about the gaits of the pronghorn, as follows. In this species,

• under which circumstances does ambling occur?
• why - in adaptive terms - has the pronghorn retained a cross-walking gait, despite otherwise conforming to 'plains game'? and
• why does stotting occur mainly for intraspecific display and in adults, rather than - as in most other ruminants - mainly for anti-predator display and in infants and juveniles?

Also see

• https://www.inaturalist.org/journal/milewski/52136-the-mane-as-a-little-known-aspect-of-the-erectile-bleeze-of-the-pronghorn-antilocapra-americana#
• https://www.inaturalist.org/posts/52201-the-peculiar-showiness-of-the-subauricular-gland-of-the-pronghorn-antilocapra-americana#
• https://www.inaturalist.org/posts/52221-why-the-pronghorn-antilocapra-americana-has-a-striped-neck#
• https://www.inaturalist.org/journal/milewski/52296-interpreting-the-buccal-semet-of-the-pronghorn-antilocapra-americana#

@beartracker @magcl @ptexis

It is widely known that the walking gait of giraffes (Giraffa) is unusual (https://www.researchgate.net/figure/Categorisation-of-giraffes-walking-gait-Reproduction-of-Hildebrands-plot-for_fig3_329382181 and https://academic.oup.com/jmammal/article-abstract/41/2/282/933378?redirectedFrom=PDF&login=false).

However, like many 'factoids' about Nature, this is subject to context.

It is true that giraffes have a 'parallel', not a 'diagonal', stride while walking (https://www.youtube.com/watch?v=n9redgIffu4 and https://www.youtube.com/watch?v=FBz1rQ5z8uE and https://www.facebook.com/watch/?v=1723826704314545and https://www.youtube.com/watch?v=Vh2yveXTKaU and https://www.youtube.com/watch?v=o9TuZCG1f0k).

However, the same is true also for many Carnivora.

The lion (Panthera leo), walking behind its intended prey, a giraffe, uses the same 'parallel' stride (https://www.youtube.com/watch?v=o9TuZCG1f0k and https://www.youtube.com/watch?v=-QnyACx936I and https://stock.adobe.com/images/big-lion-walking-shot-in-profile/210044363 and https://www.africanreferencephotos.com/photo/2209/Profile-of-Male-Lion-Walking.html).

And, in turn, the lion walks similarly to the brown bear (Ursus arctos, https://stock.adobe.com/search?k=bear+walking&asset_id=298297872 and https://stock.adobe.com/search?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=1&filters%5Bcontent_type%3Atemplate%5D=1&filters%5Bcontent_type%3A3d%5D=1&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=bear+walking&order=relevance&safe_search=1&limit=100&search_page=2&get_facets=0&search_type=pagination&asset_id=129616916).

(Yes, it is true that the brown bear walks like a giraffe, in the sense that the hind foot lifts only once the opposite fore foot has landed, and the hind foot lands (i.e. 'oversteps') considerably anterior to the print of the fore foot on the same side.)

Why is it, then, that this 'parallel' stride is seen as remarkable in giraffes, but not in Carnivora - including the domestic dog (Canis familiaris, https://www.youtube.com/watch?v=eqBcBsmMQVA)?

The obvious answer is:
because a gait that is normal in a plantigrade (e.g. brown bear) and digitigrade (e.g. lion) mammal seems much odder in mammals (giraffes) that are not only unguligrade, but extremely long-legged even among ungulates.

The above framing may explain, at least partly, why giraffes have a reputation for walking in an odd way.

For it is indeed remarkable that, in going from a 'flat-footed' animal, such as a bear, to an animal with 'stilts' for legs, such as a giraffe, the same gait is retained.
 
However, if this was a complete explanation, then all other hoofed mammals, including those with relatively short legs, would also walk like giraffes and Carnivora.

And this far from being true.

In fact, most ruminants walk in a different way, using a 'diagonal' stride. This applies to all deer (Cervidae, https://www.inaturalist.org/journal/milewski/91548-walking-gaits-in-cervidae-deer-tend-to-cross-walk-as-opposed-to-the-ambling-typical-of-many-bovids-part-1#) and many bovids (Bovidae, https://www.inaturalist.org/posts/85349-gaits-and-other-aspects-of-locomotion-in-hippotragin-bovids#).

Consider the tiger (Panthera tigris) following the sambar deer (Rusa unicolor) (https://www.naturepl.com/stock-photo-bengal-tiger-nature-image01234681.html and https://www.facebook.com/watch/?v=282670022702595 and https://www.youtube.com/watch?v=qX7oEFWuV2I).

The predator uses a 'parallel' stride (https://www.youtube.com/watch?v=MIBAT6BGE6U and https://www.youtube.com/watch?v=6fhAzkK_s_Y), whereas the prey uses a 'diagonal' stride (https://videohive.net/item/beautiful-male-sambar-rusa-unicolor-deer-walking-in-the-forest-of-ranthambore-national-park/25553355 and https://www.shutterstock.com/da/video/clip-1086299906-medium-shot-alert-male-sambar-deer-rusa and https://www.shutterstock.com/da/video/clip-1104756293-sambar-deer-rusa-unicolor-walking-carefully-dense).

One explanation for this anomaly is as follows.

Unguligrady is an adaptation mainly for rapid and enduring fleeing from predators. In the 'arms-race' between prey and predator, hoofed mammals have compensated for the disadvantage of being surprised by predators, by having more efficient sprinting than that of Carnivora.

However, all benefits are accompanied by certain costs. And in the case of ruminants, a cost of 'living on stilts' (= unguligrady) is the risk of instability while walking.

Ruminants compensate for this risk by tending to use diagonal patterns in their walking strides.

This allows deer, for example,

• to pick their way quietly through the undergrowth, then 'freeze' on two legs upon hearing an ominous rustling, and
• to wade through water and snow, and to step over fallen logs, in the case of the species of deer with the longest legs, namely the moose (Alces alces, https://www.shutterstock.com/da/video/clip-1110160859-bull-moose-walks-off-road-into-wilderness and https://www.youtube.com/watch?v=zUE5FK3l_Lo and https://www.youtube.com/watch?v=MV3yLbKke-c).

It is only in two categories of ruminants that all 'diagonality' seems to have been abandoned while walking.

These are

• giraffes, which achieve stability by means of the cantilever-effect of the long and massive neck, and
• 'plains game', adapted to open environments where hiding is impractical, and compensating for this in various ways in their anti-predator strategies.

'Plains game' artiodactyls emphasise efficiency of walking over stability of walking. This is, hypothetically, why they use a 'parallel' stride, rather than a 'diagonal stride (https://www.youtube.com/watch?v=0WcG532I4is and https://www.google.com.au/search?sca_esv=361d108b9e725553&sxsrf=ACQVn0_rxEkkCe56q3nf8k8XrPxMiTH8Hw:1712749994086&q=Wildebeest+walking+video&tbm=vid&source=lnms&prmd=visnmbtz&sa=X&ved=2ahUKEwi_vPH3yreFAxUrVmwGHb1bClcQ0pQJegQIDBAB&biw=1004&bih=549&dpr=2.7#fpstate=ive&vld=cid:2130b2ac,vid:-_if9UL39Lc,st:0). Their walking gaits are like that of giraffes, but for different reasons.

So, where do impalas fit into this conceptual framework?

Well, impalas walk like giraffes (https://www.inaturalist.org/posts/49366-locomotory-and-postural-peculiarities-of-impalas-aepyceros-part-1#activity_comment_b2dbc656-b062-4be7-9b31-eb6fdd6dc640).

This can perhaps best be explained by comparing impalas with alcelaphin bovids (Alcelaphini).

Alcelaphins (wildebeests, hartebeests, and damalisks) epitomise 'plains game'. They are odd among ruminants in their combination of

• humped withers,
• migration/nomadism, and
• extreme speed and endurance when galloping and cantering.

It is as part of the above syndrome that the 'parallel' stride of alcelaphins, when walking, can be considered. Alcelaphins are locomotorily aberrant, as part of an extreme relationship to predation.

For their part, impalas are odd among ruminants in their combination of

• dependence on woody plants,
• sedentariness (excluding nomadism, let alone migration),
• intimate gregariousness, and
• extreme bounding while fleeing.

We can, in light of the above, think of impalas as 'plains game adapted to relatively dense vegetation' (https://www.inaturalist.org/journal/milewski/89704-can-precociality-in-the-colouration-of-impalas-aepyceros-be-explained-by-their-confusing-nature-as-sedentary-plains-game-part-1#).

This would place them - albeit with some 'sheohorning' - into the third category above, namely 'plains game'.

And this leads us to realise something shared by all the ruminants that use 'parallel' - as opposed to 'diagonal' - strides while walking, namely an inability/reluctance to use the ordinary running method known as trotting (https://www.inaturalist.org/posts/49366-locomotory-and-postural-peculiarities-of-the-impala-part-1#).

A trot is a 'diagonal' way of running. It is a standard gait in Carnivora and ungulates.

However, it is

• absent in giraffes,
• used by wildebeests and hartebeests only for display, and
• peculiarly absent in impalas.

All of these ruminants have - in their own ways and for different reasons - abandoned trotting, as a gait for fleeing and commuting. It is in light of this common denominator that their adoption of a 'parallel' stride, when walking, can be appreciated.

What, then, should we call the 'parallel' gait used by giraffes, camels, 'plains game', and impalas alike?

I suggest that the best term is 'an amble'.

(This is not to be confused with a pace, which is also uses 'parallel' strides, but is a running gait, not a walking one.)

And this means that - to everyone's surprise - impalas and giraffes are evolutionarily convergent in ambling while walking (https://www.youtube.com/watch?v=K24qSp49HHg and https://www.youtube.com/watch?v=4jeoFaKDb70).

This is despite the obvious differences between impalas and giraffes in

• body size and shape (https://pixabay.com/photos/giraffes-impala-safari-animals-5916620/ and https://www.shutterstock.com/da/image-photo/giraffe-impala-kruger-national-park-south-79715629 and https://www.alamy.com/giraffe-and-black-faced-impala-at-a-waterhole-image225907584.html and https://www.alamy.com/giraffe-couple-and-impala-in-kruger-national-park-south-africa-specie-giraffa-camelopardalis-family-of-giraffidae-image242053468.html and https://www.mediastorehouse.com.au/fine-art-storehouse/giraffe-giraffa-camelopardis-blacked-faced-12529903.html), and
• ways of fleeing from predators.

Furthermore, any preoccupation that giraffes walk oddly - which remains true in its way but is easily misinterpreted - may now have been overtaken. The more current notion - given the ordinariness of their body-proportions - should be that impalas walk even more oddly.

And this invites the next step in my investigative stroll, as follows.

Warthogs (Phacochoerus) - equally surprisingly - seem to amble (https://www.inaturalist.org/posts/85161-variation-in-walking-gaits-in-ungulates-part-1-why-some-hoofed-mammals-cross-walk-whereas-others-amble#activity_comment_1c97f582-aac3-4d6d-b15f-c533aaba47b5).

This is in keeping with impalas inasmuch as these aberrant suids are 'plains game'. However, the new complication is that warthogs have certainly retained a trotting gait...

Please also see

• https://www.inaturalist.org/journal/milewski/85161-variation-in-walking-gaits-in-ungulates-part-1-why-some-hoofed-mammals-cross-walk-whereas-others-amble#, and
• https://www.inaturalist.org/journal/milewski/79019-field-notes-from-an-excursion-with-the-dromedary-camelus-dromedarius-northern-kenya-1990-1991#

:

The Rocky Mountain mule deer (Odocoileus hemionus hemionus) is well-known to have a conspicuous pattern of colouration on the hindquarters.

This is most noticeable in the winter pelage, and in posteriolateral view (https://www.inaturalist.org/observations/97295280 and https://www.inaturalist.org/observations/72504627 and https://www.inaturalist.org/observations/68344771 and https://www.inaturalist.org/observations/61732504).

However, what also requires description and explanation is a conspicuous pattern on the forequarters, which is most noticeable in profile and in a posture in which the inner foreleg is exposed.

The feature in question is complex, consisting of

• conspicuously dark pelage on the brisket (https://www.merriam-webster.com/dictionary/brisket),
• conspicuously dark pelage on the ventral surface of the thorax (https://www.inaturalist.org/observations/45881470),
• conspicuously pale pelage on the entire inner surface of the upper foreleg (including the axilla, https://www.merriam-webster.com/dictionary/axilla), and
• conspicuously pale pelage on the inner and posterior surface of the lower foreleg.

In having a conspicuously pale inner surface, the foreleg differs from the hindleg (https://www.inaturalist.org/observations/36167595).

In this and other ways, the pattern makes little sense in terms of countershading (https://en.wikipedia.org/wiki/Countershading).

https://www.inaturalist.org/observations/101206028 and https://www.inaturalist.org/observations/101171620

https://www.inaturalist.org/observations/97075871

https://www.inaturalist.org/observations/75142350

https://www.inaturalist.org/observations/69512342

https://www.inaturalist.org/observations/68901309

https://www.inaturalist.org/observations/54358694

https://www.inaturalist.org/observations/52417150

https://www.inaturalist.org/observations/51659800

https://www.inaturalist.org/observations/16922321

https://www.inaturalist.org/observations/10708031

https://www.inaturalist.org/observations/4126822

https://www.inaturalist.org/observations/3213126

https://www.inaturalist.org/observations/205313614 and https://www.inaturalist.org/observations/205313616 and https://www.inaturalist.org/observations/205313613

There is a white patch on the hindquarters of Capreolus, in winter pelage.

This constitutes a flag if unexpanded (https://www.inaturalist.org/observations/200496200).

The same feature constitutes a bleeze if expanded.

This is a difference of scale, effected by complex piloerection.

This piloerection occurs sometimes when the figure is stationary, and sometimes when the figure is fleeing.

Then feature in question can be called ischioperineal, because it is located on the buttocks and the perineum, which connects the left and right buttocks.

unexpanded, constituting an ischioperineal flag:

https://www.inaturalist.org/observations/196664785

https://www.inaturalist.org/observations/200990145

https://www.inaturalist.org/observations/201069507

https://www.inaturalist.org/observations/202679662

https://www.inaturalist.org/observations/202192789

expanded, constituting an ischioperineal bleeze:

https://www.inaturalist.org/observations/197850307

https://www.inaturalist.org/observations/203074169

https://www.inaturalist.org/observations/202864456

expanded or not, according to individual:

https://www.inaturalist.org/observations/200720752

https://www.inaturalist.org/observations/201122384

https://www.inaturalist.org/observations/200929949

https://www.inaturalist.org/observations/196352729

@matthewinabinett @jeremygilmore @tonyrebelo @variani18 @christiaan_viljoen @paradoxornithidae @beartracker @chewitt1 @gareth_bain

Please also see the following

• https://www.inaturalist.org/journal/milewski/85161-variation-in-walking-gaits-in-ungulates-why-some-hoofed-mammals-cross-walk-whereas-others-amble-part-1#
• https://www.inaturalist.org/journal/milewski/91548-walking-gaits-in-cervidae-deer-tend-to-cross-walk-as-opposed-to-the-ambling-typical-of-many-bovids-part-1#
• https://www.youtube.com/watch?v=nh9e1xoUJ4Q

INTRODUCTION

A cross-walk is a diagonal walking gait, in which left fore tends to move together with right hind, and right fore tends to move together with left hind.

Among ungulates, a 'perfect' example is Hippopotamus amphibius (https://www.pond5.com/stock-footage/item/56467947-hippo-walking-isolated-hippopotamus-video-includes-alpha-cha).

Cross-walking occurs in certain small (body mass less than 35 kilograms) ruminants. More particularly, I refer to cover-dependent, nocturnal, solitary species with inconspicuous colouration (https://www.inaturalist.org/journal/milewski/91630-walking-gaits-in-cervidae-deer-tend-to-cross-walk-as-opposed-to-the-ambling-typical-of-many-bovids-part-2-odocoileinae#).

However, a naturalist can observe these ruminants attentively without noticing that the gait is a cross-walk.

Furthermore, baboons (Papio spp.), macaques (Macaca spp.), and the proboscis monkey (Nasalis larvatus) - all of which habitually cross-walk on the ground - seem to have yet another different action (https://www.gettyimages.com.au/detail/photo/proboscis-monkey-walking-through-mangrove-royalty-free-image/527127928?phrase=proboscis+monkey&adppopup=true and https://www.gettyimages.com.au/detail/photo/proboscis-monkey-walking-through-mangrove-swamp-royalty-free-image/114995835?phrase=proboscis+monkey&adppopup=true).

However, here again, the gait is a cross-walk.

So, how can these disparate impressions be reconciled?

A NOTE ON TECHNICAL TERMS

A problem in studying gaits is confusion of terms.

What I call a cross-walk is alternatively called a 'walking trot' or 'diagonal-sequence walk' (https://onlinelibrary.wiley.com/doi/abs/10.1002/ajpa.1330260203#:~:text=Diagonal%2Dsequence%20gaits%20have%20the,opposite%20side%20of%20the%20body).

'Diagonal-couplets gaits' (see the reference above) include both a running gait (trot) and a walking gait (which I call a cross-walk).

What I call an amble is alternatively called a 'walking pace' or 'lateral-sequence walk'. In my terminology, just as a trot is the running version of a cross-walk, so a pace is the running version of an amble.

I have invented the term 'semi cross-walk' because

• the 'normal' or 'default' walking gaits in unguligrade mammals are intermediate between 'diagonal-sequence' and 'lateral-sequence' gaits, and
• there has been no apt term for this in the literature - the detailed work of Innis Dagg (https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2907.1973.tb00179.x and https://originalwisdom.com/wp-content/uploads/bsk-pdf-manager/2019/03/Dagg_1973_Gaits-in-mammals.pdf and https://uwspace.uwaterloo.ca/handle/10012/14529) and Hildebrand (https://www.originalwisdom.com/wp-content/uploads/bsk-pdf-manager/2019/04/Hildebrand_1977_Analysis-of-Asymmetrical-Gaits.pdf and https://academic.oup.com/jmammal/article-abstract/58/2/131/892924?login=false) notwithstanding.

AIMS

The aim of this Post is to explain why the walking gaits seem so different in ruminants and monkeys that it took me decades to realise that both kinds of mammals cross-walk.

RESULTS AND DISCUSSION

Please compare

• Mazama https://www.inaturalist.org/observations/184029864 and https://www.inaturalist.org/observations/148448279 with
• Papio https://www.inaturalist.org/observations/197758249 and Nasalis https://www.naturepl.com/stock-photo-proboscis-monkey-nasalis-larvatus-male-walking-on-the-mudflats-of-a-image01352001.html

Which reader would have known that all of these photos illustrate cross-walking?

There are six main reasons why cross-walking in ruminants and monkeys seems to consist of categorically different gaits.

These are as follows.

In the ruminants,

• the hind foot is placed after the opposite fore foot is placed (https://www.inaturalist.org/observations/148448278); by contrast, in the monkeys, the hind foot is placed before the opposite fore foot is placed (https://www.youtube.com/watch?v=EZhO2dhlIFI and https://www.sciencephoto.com/media/1223177/view/chacma-baboon-walking);
• the hind foot superimposes on the print of the fore foot on the same side; by contrast, in the monkeys the hind foot lands to the side of the fore foot (https://depositphotos.com/photo/male-hamadryas-baboon-77413598.html);
• cross-walking tends to occur only in furtive/halting locomotion; by contrast, in the monkeys, cross-walking terrestrially tends to occur with a bold demeanour;
• the feet tend to be lifted high off the ground, as if to avoid making rustling sounds against low plants; by contrast, in the monkeys, the feet swing low;
• some spp. may tend to bob the head back and forth in synchrony with their limb-movements; by contrast, all the monkeys hold the head steady; and
• the figure intermittently 'freezes' vigilantly/suspiciously with one or two feet suspended off the ground (https://www.inaturalist.org/observations/145704914 and https://www.inaturalist.org/observations/143222891 and https://www.inaturalist.org/observations/173412545 ); by contrast, in the monkeys, there is no sudden cessation of movement in an attempt to blend into the environment in concealment from predators.

Part of the reason why ruminants and monkeys deviate, in opposite directions, from the synchronous placement of the diagonally-opposite feet may be

• their different body-proportions, and
• the fact that the former are unguligrade, whereas the latter are plantigrade (hind) and facultatively digitigrade (fore, https://mammals-locomotion.com/walking.html).

In the ruminants in question, the rump is higher than the withers (https://www.inaturalist.org/observations/83544190). This is part of a 'hunched' conformation in which - presumably to boost acceleration when predators pounce - the hind legs are longer and springier than the fore legs.

In the monkeys in question, the rump tends to be lower than the withers (https://es.123rf.com/photo_126109982_a-monkey-walking-in-the-street-on-the-sunny-day.html).

This is because

• there is an 'ape-like' conformation, with relatively long fore legs that facilitate climbing, and
• the hind feet are plantigrade (https://en.wikipedia.org/wiki/Plantigrade).

Both the ruminants and the monkeys deviate from Hippopotamus amphibius, in which fore and hind legs are similar in length (https://www.shutterstock.com/image-photo/rare-sighting-hippo-walking-out-water-60570064).

Therefore,

• the proportionately long hind leg of the ruminants takes a long time to swing fully from lifting to placement, thus landing well after the diagonally-opposite fore leg, whereas
• the proportionately short hind leg of the monkeys takes a short time to perform the analogous swing.

Finally, two relevant differences between the ruminants and the monkeys are that

• in adults of the latter, cross-walking is categorically the only terrestrial walking gait; by contrast, most/all of the ruminants that cross-walk are capable of grading into a semi cross-walk when walking rapidly; and
• when speeding up from walking to running, the former trot, whereas the latter immediately canter/gallop; indeed, no primate is known to trot.

Muntjaks (Cervidae: Muntiacus) occur in southern and East Asia. They are comparable with duikers (Bovidae: Cephalophus), which occur in Africa.

https://www.inaturalist.org/observations/51907267

Muntiacus feae
https://www.dreamstime.com/stock-photo-fea-muntjac-deer-s-tenasserim-muntiacus-feae-rare-species-native-to-china-laos-myanmar-thailand-image51955354 and https://www.dreamstime.com/stock-photo-fea-muntjac-deer-s-tenasserim-muntiacus-feae-rare-species-native-to-china-laos-myanmar-thailand-image51955105

Muntiacus reevesi
https://www.dreamstime.com/stunning-stag-muntjac-deer-muntiacus-reevesi-feeding-edge-woodland-beautiful-stag-muntjac-deer-muntiacus-reevesi-image139600368

Muntiacus vaginalis
https://www.dreamstime.com/southern-red-muntjac-crossing-path-forest-kaziranga-deer-species-native-to-south-asia-southern-red-image286131596

However, there is a categorical difference between muntjaks and duikers, w.r.t. caudal flagging.

In muntjaks, the tail is relatively large, with white pelage on its ventral side (https://www.inaturalist.org/observations/41672710 and https://www.alamy.com/stock-photo-muntjac-deer-muntiacus-reevesi-tail-uplifted-visual-signal-of-apprehension-27334104.html).

The white extends variably around the perineum and on to the inner surface of the upper hind legs (https://www.inaturalist.org/observations/196475597 and https://www.dreamstime.com/side-profile-barking-deer-muntjac-indian-muntjac-red-muntjac-muntiacus-muntjak-antler-winter-season-evening-image290333571).

The white surface is starkly displayed by erecting the tail.

Muntiacus reevesi (https://www.dreamstime.com/stock-photo-chinese-muntjac-muntiacus-reevesi-also-known-as-reeves-s-wildlife-animal-image56542499 and https://newforestguide.uk/biodiversity/new-forest-deer/muntjac-deer/):

displayed when fleeing

https://www.alamy.com/stock-photo-muntjac-deer-running-away-showing-white-flash-under-tail-21609669.html

https://www.inaturalist.org/observations/194582416

https://www.inaturalist.org/observations/193973921

https://www.inaturalist.org/observations/106546121

https://www.inaturalist.org/observations/80361071

https://www.inaturalist.org/observations/48649354

https://www.inaturalist.org/observations/41828696

https://www.inaturalist.org/observations/10593946

https://www.inaturalist.org/observations/203262951

https://www.inaturalist.org/observations/153367326

https://www.alamy.com/rear-view-of-a-muntjac-deer-with-its-tail-up-in-the-forest-of-dean-image416053307.html

displayed by infants and juveniles during suckling

https://www.inaturalist.org/observations/46359553

Muntiacus vaginalis:

https://www.inaturalist.org/observations/110068081

https://www.dreamstime.com/stock-photo-muntjac-national-park-photo-taken-resting-tree-image89607003

https://www.dreamstime.com/stock-photo-muntjac-national-park-photo-taken-resting-tree-image89606944

https://www.dreamstime.com/stock-photo-muntjac-national-park-photo-taken-resting-tree-image89606982

...continued from https://www.inaturalist.org/journal/milewski/91548-walking-gaits-in-cervidae-deer-tend-to-cross-walk-as-opposed-to-the-ambling-typical-of-many-bovids-part-1#

Capreolus capreolus

semi cross-walking:

https://www.istockphoto.com/video/roe-deer-in-forest-capreolus-capreolus-wild-roe-deer-in-nature-gm1258088372-368901841

https://www.inaturalist.org/observations/199708491

cross-walking:

https://www.google.com.au/search?sca_esv=f2adb3232492c0ce&sxsrf=ACQVn09Tjjrr9IEYFOVSCMyxOX02LhQHPQ:1712372277510&q=Roe+deer+walking&tbm=vid&source=lnms&prmd=ivsnmbtz&sa=X&ved=2ahUKEwif0cvqy6yFAxVY8zgGHelGB78Q0pQJegQIChAB&biw=1004&bih=549&dpr=2.7#fpstate=ive&vld=cid:09951b84,vid:v0Txa1m6x7M,st:0

https://www.inaturalist.org/observations/200526626

https://www.inaturalist.org/observations/200529744

https://www.dreamstime.com/roe-deer-doe-walking-meadow-side-view-winter-capreolus-sunrise-wild-mammal-brown-fur-ears-moving-cold-image171306341

https://www.shutterstock.com/da/video/clip-1107586537-roe-deer-walking-grassy-field-on-cloudy

https://www.inaturalist.org/observations/198722454

https://www.inaturalist.org/observations/198151250

https://www.shutterstock.com/da/video/clip-1103477551-roe-deer-buck-walking-on-grass-leaving

https://www.shutterstock.com/da/video/clip-1083644467-roe-deer-buck-walking-away-on-meadow

https://www.alamy.com/roe-deer-capreolus-capreolus-buck-with-big-antlers-covered-in-velvet-walking-wild-animal-in-winter-roebuck-sheding-velvet-image245974877.html

https://www.inaturalist.org/observations/204763226

https://www.inaturalist.org/observations/203396739

https://www.inaturalist.org/observations/201018719

https://www.inaturalist.org/observations/200007095

https://www.inaturalist.org/observations/199210578

https://www.inaturalist.org/observations/196991254

https://www.inaturalist.org/observations/196921690

https://www.inaturalist.org/observations/196750115 and https://www.inaturalist.org/observations/196750113 and https://www.inaturalist.org/observations/196750111

https://www.inaturalist.org/observations/196499529

Capreolus pygargus

semi-cross-walking:

https://www.inaturalist.org/observations/200166126

cross-walking:

https://www.inaturalist.org/observations/200226838

https://www.inaturalist.org/observations/165683650

https://www.inaturalist.org/observations/140516971

https://www.inaturalist.org/observations/130955769

https://www.inaturalist.org/observations/54859342

cross-walking while wading:

https://www.inaturalist.org/observations/161169776

cross-walking through deep snow:

https://www.inaturalist.org/observations/144851337

Odocoileus hemionus columbianus

semi cross-walking:

https://dpa730eaqha29.cloudfront.net/myedmondsnews/wp-content/uploads/2023/05/DSC_5193.jpg

https://www.istockphoto.com/video/deer-grazing-in-the-summit-area-of-the-olympic-national-park-washington-usa-gm1330945675-414222727

https://www.istockphoto.com/video/deer-grazing-in-the-summit-area-of-the-olympic-national-park-washington-usa-gm1330981359-414249919

Odocoileus hemionus hemionus

semi cross-walking:

https://www.inaturalist.org/observations/151441827

https://www.inaturalist.org/observations/153380171

https://www.inaturalist.org/observations/182313300

https://www.inaturalist.org/observations/168885353

https://www.inaturalist.org/observations/161671222

https://www.inaturalist.org/observations/96031618

https://www.inaturalist.org/observations/75142350

https://www.inaturalist.org/observations/64994632

https://www.inaturalist.org/observations/35272267

https://www.inaturalist.org/observations/9075740

cross-walking:

https://www.inaturalist.org/observations/8028821

https://www.inaturalist.org/observations/8736525

https://www.inaturalist.org/observations/189540198

https://www.inaturalist.org/observations/204305029

https://www.shutterstock.com/da/image-photo/buck-deer-walks-across-highway-on-111051494

https://www.inaturalist.org/observations/202004530

https://www.inaturalist.org/observations/190620659

https://www.inaturalist.org/observations/179621347

https://www.inaturalist.org/observations/166485874

https://www.inaturalist.org/observations/161671220

https://www.inaturalist.org/observations/161266256

https://www.inaturalist.org/observations/156841911

https://www.inaturalist.org/observations/151840118

https://www.inaturalist.org/observations/151840115

https://www.inaturalist.org/observations/151441917

https://www.inaturalist.org/observations/149782171

https://www.inaturalist.org/observations/149782168

https://www.inaturalist.org/observations/145480214

https://www.inaturalist.org/observations/143050642

https://www.inaturalist.org/observations/141660923

https://www.inaturalist.org/observations/139533281

https://www.inaturalist.org/observations/131760773

https://www.inaturalist.org/observations/126746210

https://www.inaturalist.org/observations/121896584

https://www.inaturalist.org/observations/108006039

https://www.inaturalist.org/observations/104745347

https://www.inaturalist.org/observations/101383253

https://www.inaturalist.org/observations/97075871

https://www.inaturalist.org/observations/93931119

https://www.inaturalist.org/observations/71169031

https://www.inaturalist.org/observations/67847612

https://www.inaturalist.org/observations/58985402

https://www.inaturalist.org/observations/55758196

https://www.inaturalist.org/observations/54936480

https://www.inaturalist.org/observations/54582566

https://www.inaturalist.org/observations/54358694

https://www.inaturalist.org/observations/50999255

https://www.inaturalist.org/observations/35796761

https://www.inaturalist.org/observations/29877618

https://www.inaturalist.org/observations/20794403

https://www.inaturalist.org/observations/15346766

https://www.inaturalist.org/observations/4126822

https://www.inaturalist.org/observations/36048874 and https://www.inaturalist.org/observations/36048227

https://www.inaturalist.org/observations/36167603 and https://www.inaturalist.org/observations/36170547 and https://www.inaturalist.org/observations/36167946 and https://www.inaturalist.org/observations/36167597

https://www.inaturalist.org/observations/100968396 and https://www.inaturalist.org/observations/100968394 and https://www.inaturalist.org/observations/100968393

cross-walking while wading:

https://www.inaturalist.org/observations/4828950

Odocoileus virginianus

semi cross-walking:

https://www.istockphoto.com/video/whitetail-deer-9pt-buck-walks-across-a-frozen-field-gm1412980972-462212996

https://www.shutterstock.com/da/video/clip-1025463410-large-swamp-buck-white-tail-deer-walks-across

https://stock.adobe.com/images/walking-whitetail-deer-in-morning-sun/276397346

https://es.123rf.com/photo_32305362_deer-walking.html

https://www.fieldandstream.com/hunting/whitetail-deer-travels-200-miles/

https://dpa730eaqha29.cloudfront.net/myedmondsnews/wp-content/uploads/2023/05/DSC_5193.jpg

https://www.shutterstock.com/da/image-photo/group-whitetailed-deer-odocoileus-virginianus-crossing-1511428202

Blastoceros dichotomus

semi cross-walking:

https://www.shutterstock.com/da/video/clip-33283189-marsh-deer-blastocerus-dichotomus-calmly-walking-beside

https://www.shutterstock.com/da/video/clip-33283579-marsh-deer-blastocerus-dichotomus-calmly-walking-beside

https://www.inaturalist.org/observations/8996008

cross-walking:

https://www.inaturalist.org/observations/196758832

https://www.inaturalist.org/observations/170839025

https://www.inaturalist.org/observations/53881033

https://www.inaturalist.org/observations/42970432

https://www.inaturalist.org/observations/41561276

https://www.inaturalist.org/observations/37990878

https://www.inaturalist.org/observations/34235604

https://www.inaturalist.org/observations/28863071

cross-walking while wading:

https://www.inaturalist.org/observations/102046322

https://www.inaturalist.org/observations/182656187

https://www.inaturalist.org/observations/97958718

https://www.inaturalist.org/observations/93946424

https://www.inaturalist.org/observations/34574865

https://www.inaturalist.org/observations/32539691

Hippocamelus bisulcus

semi cross-walking:

https://www.inaturalist.org/observations/168732894

https://www.inaturalist.org/observations/61948658

https://www.inaturalist.org/observations/56866303

cross-walking:

https://www.inaturalist.org/observations/142966285

https://www.inaturalist.org/observations/35047742

cross-walking while wading:

https://www.inaturalist.org/observations/145285980

Ozotoceros bezoarticus

semi cross-walking:

https://www.inaturalist.org/observations/188266170

https://www.inaturalist.org/observations/127628739

https://www.inaturalist.org/observations/116406102

cross-walking:

https://www.inaturalist.org/observations/173585378

https://www.inaturalist.org/observations/165578454

https://www.inaturalist.org/observations/127628734

https://www.inaturalist.org/observations/122319144

https://www.inaturalist.org/observations/122317603

https://www.inaturalist.org/observations/53328279

https://www.inaturalist.org/observations/47876146

https://www.inaturalist.org/observations/37990891

Mazama americana

semi cross-walking:

https://www.inaturalist.org/observations/119498924

https://www.inaturalist.org/observations/138744138

https://www.inaturalist.org/observations/131921519

https://www.inaturalist.org/observations/71754872

cross-walking:

https://www.inaturalist.org/observations/204020861

https://www.inaturalist.org/observations/203355223

https://www.inaturalist.org/observations/196351425

https://www.inaturalist.org/observations/194197274 and https://www.inaturalist.org/observations/194197204

https://www.inaturalist.org/observations/121656531

https://www.inaturalist.org/observations/37658132

https://www.inaturalist.org/observations/23438426

Mazama gouazoubira

semi cross-walking:

https://www.inaturalist.org/observations/202457732

https://www.inaturalist.org/observations/201190211

https://www.inaturalist.org/observations/200765159

https://www.inaturalist.org/observations/157219695

https://www.inaturalist.org/observations/148936440

https://www.inaturalist.org/observations/148341817

https://www.inaturalist.org/observations/143891805

https://www.inaturalist.org/observations/139570557

https://www.inaturalist.org/observations/110835932

https://www.inaturalist.org/observations/72306746

https://www.inaturalist.org/observations/67207093

https://www.inaturalist.org/observations/36736828

cross-walking:

https://www.inaturalist.org/observations/148448278

https://www.inaturalist.org/observations/148448279

https://www.inaturalist.org/observations/184029864

https://www.inaturalist.org/observations/199002954

https://www.inaturalist.org/observations/197787941

https://www.inaturalist.org/observations/196664385

https://www.inaturalist.org/observations/194224925

https://www.inaturalist.org/observations/193392785

https://www.inaturalist.org/observations/192166170

https://www.inaturalist.org/observations/191960797

https://www.inaturalist.org/observations/189964790

https://www.inaturalist.org/observations/162172015

https://www.inaturalist.org/observations/152167632

https://www.inaturalist.org/observations/147677512

https://www.inaturalist.org/observations/139184975

https://www.inaturalist.org/observations/137344367

https://www.inaturalist.org/observations/134508704

https://www.inaturalist.org/observations/131522623

https://www.inaturalist.org/observations/123754502

https://www.inaturalist.org/observations/118417376

https://www.inaturalist.org/observations/67065366

https://www.inaturalist.org/observations/65598410

https://www.inaturalist.org/observations/57609044

https://www.inaturalist.org/observations/37614428

https://www.inaturalist.org/observations/18507794

https://www.inaturalist.org/observations/15860143

https://www.inaturalist.org/observations/15860485

https://www.inaturalist.org/observations/9420813

https://www.inaturalist.org/observations/9072964

Mazama nemorivaga

semi cross-walking:

https://www.inaturalist.org/observations/148931933

https://www.inaturalist.org/observations/147831648

cross-walking:

https://www.inaturalist.org/observations/103476694

https://www.inaturalist.org/observations/103476646

Mazama temama

semi cross-walking:

https://www.inaturalist.org/observations/74340594

cross-walking:

https://www.inaturalist.org/observations/176219423

https://www.inaturalist.org/observations/203504965

https://www.inaturalist.org/observations/177935431

Alces alces

semi-cross-walking:

https://www.youtube.com/watch?v=VUVBr_jDBcQ

https://www.deviantart.com/nini1965/art/A-Young-Bull-Moose-Walking-in-a-Field-917220578

https://www.shutterstock.com/image-photo/profile-bull-moose-walking-onto-dirt-116525839

https://a57.foxnews.com/global.fncstatic.com/static/managed/img/fn2/video/876/493/edge_moose_052014.jpg?ve=1&tl=1

https://www.istockphoto.com/photo/bull-moose-gm1055977806-282201912

https://fineartamerica.com/featured/walking-bull-moose-randy-straka.html

https://www.alamy.com/bull-moose-denali-national-park-preserve-alaska-united-states-of-america-a-unique-optimised-version-of-an-image-by-nps-ranger-jw-frank-credit-npsjacob-w-frank-image454466690.html?imageid=DC229BEB-798B-4807-AFC7-245D832C911F&p=1837101&pn=1&searchId=acbc6be48e9684687a1dabcb59018a60&searchtype=0

https://pixels.com/featured/bull-moose-crossing-river-jack-bell.html?product=wood-print

cross-walking: see A new observation on gaits in the maternal defensive behaviour in the moose (Alces alces)#

Rangifer tarandus

semi cross-walking:

https://www.shutterstock.com/da/image-photo/sweden-beautiful-deer-midst-spring-tundra-1265271187

https://www.alamy.com/stock-photo-reindeer-walking-on-snow-83046876.html

https://www.alamy.com/reindeer-walking-on-the-road-in-norway-image339946013.html

https://www.sciencephoto.com/media/956135/view/reindeer-male-walking-across-beach-in-winter-iceland

https://www.westend61.de/en/photo/RUNF04398/reindeer-with-big-antlers-walking-on-road-nordkapp-norway

https://www.inaturalist.org/observations/194973788

https://www.inaturalist.org/observations/188771774

https://www.inaturalist.org/observations/176450543

Rangifer tarandus caribou

semi cross-walking:

https://www.inaturalist.org/observations/14285540

https://www.inaturalist.org/observations/96124667

https://www.inaturalist.org/observations/108555074

https://www.inaturalist.org/observations/188361965

https://www.inaturalist.org/observations/104384160

https://www.inaturalist.org/observations/34116020

cross-walking:

The following series of photos shows the footfall-sequence: https://www.inaturalist.org/observations/188323834

https://www.inaturalist.org/observations/189059963 and https://www.inaturalist.org/observations/196236142

https://www.inaturalist.org/observations/38014346

https://www.inaturalist.org/observations/12796121

Rangifer tarandus granti

cross-walking:

https://www.inaturalist.org/observations/154738951

Rangifer tarandus groenlandicus

semi cross-walking:

https://www.inaturalist.org/observations/112211957

https://www.inaturalist.org/observations/54094260

cross-walking:

https://www.inaturalist.org/observations/8533464

Rangifer tarandus platyrhynchus

semi cross-walking:

https://www.inaturalist.org/observations/34390801

https://www.inaturalist.org/observations/204713654

https://www.inaturalist.org/observations/203494818

https://www.inaturalist.org/observations/174623820

https://www.inaturalist.org/observations/173065059

https://www.inaturalist.org/observations/147914529

https://www.inaturalist.org/observations/139973692

https://www.inaturalist.org/observations/69812260

https://www.inaturalist.org/observations/35598095

https://www.inaturalist.org/observations/8606357

cross-walking:

https://www.inaturalist.org/observations/133664259

https://www.inaturalist.org/observations/34390803

https://www.inaturalist.org/observations/27762495

Pudu puda

semi cross-walking:

https://www.youtube.com/watch?v=vea0C2YnKW8

Hydropotes inermis

semi cross-walking:

https://www.youtube.com/watch?v=75UJqMLIHrQ

https://www.youtube.com/watch?v=Xg0tRDdWNQY

cross-walking while wading:

https://www.vecteezy.com/photo/27808124-chinese-water-deer-walking-across-shallow-marshes

https://www.youtube.com/watch?v=pjJJN9XhuyU

to be continued in https://www.inaturalist.org/journal/milewski/91587-walking-gaits-in-cervidae-deer-tend-to-cross-walk-as-opposed-to-the-ambling-typical-of-many-bovids-part-3-discussion#...

...continued from https://www.inaturalist.org/journal/milewski/91630-walking-gaits-in-cervidae-deer-tend-to-cross-walk-as-opposed-to-the-ambling-typical-of-many-bovids-part-2-odocoileinae#

DISCUSSION

https://www.inaturalist.org/observations/60154859

It is unsurprising that I have found photographic evidence of all species of deer semi cross-walking.

In ungulates generally, the least remarkable gait is a semi cross-walk.

This is because

• the semi cross-walk is an intermediate, unspecialised gait, neither as committed to stability as the cross-walk, nor as committed to energetic efficiency as the amble, and
• in unguligrade mammals, the functional equivalent - simply owing to proportional leg-length - of the normal 'one step at a time' walking gait of digitigrade mammals (e.g. Felidae ), is a semi cross-walk.

However, there is a divergence among ruminants in walking gaits, with cover-dependent species erring towards cross-walking, and 'plains game' erring towards ambling.

In bovids, this divergence/dichotomy results in whole tribes, e.g. Alcelaphini and Hippotragini (https://www.inaturalist.org/journal/milewski/85349-gaits-and-other-aspects-of-locomotion-in-hippotragin-bovids#), that consistently amble.

For example:

• cover-dependent bovids, showing semi cross-walk: https://www.istockphoto.com/video/kudu-walking-gm472607841-9062520 and https://www.inaturalist.org/observations/200510219
• 'plains game' bovid, showing amble: https://www.alamy.com/a-grants-gazelle-nanger-granti-walking-tanzania-east-africa-africa-image220675045.html

This is behaviourally and ecologically correlated, as follows:

• Cover-dependent bovids tend to be nocturnal, solitary, and camouflage-coloured, with eyes facing somewhat forward.
• By contrast, 'plains game' are adapted to living in the open, with diurnal habits, gregariousness, conspicuous colouration, and eyes so far on the sides of the head that they can scan behind and in front at the same time.

The pronghorn (Antilocapra americana) belongs to a different family, viz. Antilocapridae. It conforms to the 'plains game' category, and ambles accordingly (https://es.123rf.com/photo_30436381_pronghorn-antelope-p%C3%A9rez.html).

Impalas (Aepycerotini) are a particularly interesting tribe of bovids, combining a superficially deer-like appearance with multifaceted peculiarities (https://www.inaturalist.org/posts/89229-an-index-to-my-posts-about-the-impala-aepyceros-melampus#). They seem cover-dependent, but actually conform in various ways to 'plains game'.

Accordingly, impalas amble:

• Aepyceros melampus (https://www.africaimagelibrary.com/media/e65dbf22-af1f-4b33-aea2-6e62423423c9-impala-ram-aepyceros-melampus-gondwana-game-reserve-south-af and https://www.istockphoto.com/video/beautiful-and-graceful-impala-antelope-walking-in-savannah-gm932522106-255537892)
• Aepyceros petersi (https://www.alamy.com/black-faced-impala-aepyceros-melampus-petersi-male-walking-on-savanna-etosha-national-park-namibia-image396537387.html?imageid=130B7753-D07F-4AAF-B8A8-6326847D55ED&p=157727&pn=1&searchId=2cfc4de9b1aacee4e55653a80467551f&searchtype=0 and https://www.alamy.com/male-black-faced-impala-aepyceros-melampus-petersi-by-a-waterhole-etosha-national-park-namibia-with-a-marabou-stork-in-the-background-image214783551.html?imageid=C85EC920-7966-4CB3-97DA-59AF08E61176&p=564807&pn=1&searchId=2cfc4de9b1aacee4e55653a80467551f&searchtype=0 and https://www.alamy.com/stock-photo-black-faced-impala-103307129.html?imageid=59C58C12-F2FE-449E-B7D9-860AD06CF8CC&p=310217&pn=1&searchId=2cfc4de9b1aacee4e55653a80467551f&searchtype=0).

The bovid Kobus defassa is comparable in body size and shape to the cervid Cervus canadensis. However, the former is more likely than the latter to amble (https://front.motionarray.com/stock-video/common-waterbuck-walking-between-trees-1179445/ and https://www.alamy.com/stock-photo-walking-african-waterbuck-in-wild-78946808.html).

By contrast to many bovids, no cervid normally ambles. The semi cross-walk is retained by even those species showing certain adaptations associated with 'plains game', such as

• long-range migrations (e.g. Rangifer tarandus),
• lateral vision and wide-set orbits (e.g. Cervus elaphus),
• bold colouration on the hindquarters (e.g. Dama dama, Odocoileus hemionus hemionus)

Masculine display in the rutting season does not involve a modification of gaits in Cervus elaphus, Cervus canadensis, and Elaphurus davidianus. These species 'strut' by semi cross-walking, not ambling.

Dama dama is, by contrast, versatile. In its 'strutting', this species adopts an amble under some circumstances, and a cross-walk under other circumstances..

Also see https://www.inaturalist.org/posts/84799-a-comparison-of-postures-and-gaits-between-two-elands-the-moose-alces-alces-and-the-common-eland-taurotragus-oryx#

INTRODUCTION

Ruminants walk with subtle gaits, difficult to classify and name.

My approach is to distinguish between ambling and a semi cross-walking gaits.

(Readers, please note: watch all the videos linked in this Post in slow motion, by adjusting the 'playback speed' to 0.5 or 0.25.)

In ambling, the hind foot is lifted only after the opposite fore is placed (watch from 40 seconds in slow motion in https://www.youtube.com/watch?v=9EawG4Gu3Js).

By contrast, in semi cross-walking, the hind foot is lifted before the opposite fore is placed (https://vimeo.com/407626704 and https://www.youtube.com/watch?app=desktop&v=hxkM96MYlb8 and https://www.vectorstock.com/royalty-free-vector/deer-walk-cycle-vector-31351189 and https://www.shutterstock.com/da/image-vector/deer-walkcycle-silhouette-vector-illustration-frame-1724464180).

An amble is a 'parallel gait', whereas a cross-walk is a 'diagonal gait'.

In reality, the footfall-sequence varies among species along a continuum, rather than dichotomously. Thus, a semi cross-walk is, in terms of the footfall-pattern, intermediate between a cross-walk and an amble.

However the criterion between amble and semi cross-walk is significant, because it potentially affects the balance/stability of the locomotion.

The distinction is as follows:

In ambling, for most of the time there are two feet simultaneously off the ground on the same side (left or right) - which is relatively unstable in that it risks tipping to the unsupported side.

In cross-walking, by contrast, the two feet off the ground are on different sides, viz. left fore with right hind, or right fore with left hind. This is relatively stable, because it maintains diagonal propping. An additional advantage of semi cross-walking is that two feet are off the ground simultaneously for less than half of the time.

Readers can practise distinguishing between the approximately 'parallel' walk and the approximately 'diagonal' walk by repeatedly viewing the following video clips (adjusting the playback speed to show the footfall sequence in slow motion):

• amble in Giraffa: https://www.youtube.com/watch?v=Vh2yveXTKaU
• semi cross-walk in Strepsiceros: https://www.youtube.com/watch?v=Rky362tL5kE

AIMS

The aim of thus Post is to show the walking gaits of as many genera and species as possible of cervids, according to the distinctions among ambling, semi cross-walking, and cross-walking.

RESULTS

Cervus elaphus

semi cross-walking:

https://www.freepik.com/premium-photo/red-deer-cervus-elaphus-walking-green-meadow-summertime-nature-wild-hind-marching-open-grassland-summer-female-animal-going-pasture_24217519.htm

https://www.pond5.com/stock-footage/item/85266360-hd-slow-motion-young-stag-red-deer-cervus-elaphus-walking

semi cross-walking in masculine strutting:

https://www.shutterstock.com/da/video/clip-1017907225-wild-red-deer-stag-walking-bright-morning

https://www.shutterstock.com/image-photo/red-deer-rutting-season-737170840

https://www.youtube.com/watch?v=_O9x3bQpGhw

cross-walking (on unstable substrate):

https://www.dreamstime.com/red-deer-hind-crossing-stream-water-close-up-winter-image138050863

Cervus canadensis

semi cross-walking:

https://www.dreamstime.com/grand-teton-national-park-wy-usa-september-close-up-bull-elk-cervus-canadensis-walking-across-road-traffic-stopped-image296347398

https://stock.adobe.com/es/images/wild-bull-elk-or-wapiti-walking-through-tall-frost-covered-grass-at-forest-s-edge-jasper-national-park-alberta-canada-cervus-canadensis/122577689

https://www.dreamstime.com/grand-teton-national-park-wy-usa-september-close-up-bull-elk-cervus-canadensis-walking-across-road-traffic-stopped-image296347398

https://stock.adobe.com/es/images/wild-bull-elk-or-wapiti-walking-through-tall-frost-covered-grass-at-forest-s-edge-jasper-national-park-alberta-canada-cervus-canadensis/122577689

nearly ambling:

https://www.alamy.com/stock-photo-wapiti-elk-cervus-elaphus-canadensis-cervus-canadensis-rutting-bull-76021844.html

Cervus nippon

semi cross-walking:

https://es.123rf.com/photo_91171124_a-sika-deer-walking-across-a-path-in-the-woods.html

https://www.istockphoto.com/video/young-deer-on-the-green-grass-at-the-zoo-gm1304918196-395939791

Elaphurus davidianus

semi cross-walking:

https://www.youtube.com/shorts/nDF9nyR62YQ

https://www.youtube.com/watch?v=qvuQK9M5O5w

https://www.naturepl.com/stock-photo-nature-image01617635.html

https://www.youtube.com/watch?v=s6KT9HyEqwc

https://www.youtube.com/watch?v=V-PkYSIGRl8

including during masculine strutting https://www.youtube.com/watch?v=9o-Oap1xs9M

from 12 seconds, infant semi cross-walking, despite this meaning that the hind hoof must closely displace the fore hoof on the same side in order to avoid collision between hind and fore https://www.youtube.com/watch?v=RqxIzx13FWk

nearly ambling:

https://www.staffanwidstrand.se/image/I0000NS9g.SH5Xug

https://www.shutterstock.com/da/video/clip-20558605-pere-davids-deer-herd-migrate-graze-elaphurus

from 10 seconds in https://www.youtube.com/watch?v=pItzvvhZBPA

Dama dama

semi cross-walking:

https://www.istockphoto.com/video/deer-hinds-in-harem-during-rut-in-autumn-mountain-forest-gm455379686-47417190

https://www.istockphoto.com/video/deer-hinds-in-harem-during-rut-in-autumn-mountain-forest-gm455379712-47417372

https://www.sciencephoto.com/media/625669/view/male-fallow-deer-walking

https://www.youtube.com/watch?v=dBaW7gt4Z4M

https://www.alamy.com/video/fallow-deer-male-with-winter-fur-walks-through-the-snow-dama-dama-in-the-snow-cervus-dama-in-winter-588321494.html

https://www.shutterstock.com/da/video/clip-3399380867-lonely-little-deer-walking-forest-reserve-near

mature males in masculine 'strutting'

• semi cross-walking during side-by-side rivalry (3 minutes to 3 minutes 9 seconds): https://www.youtube.com/watch?v=E3EIRxKXpDQ

• cross-walking:
  https://www.istockphoto.com/video/male-fallow-deer-in-early-morning-in-the-mountain-gm455379654-47416714 and https://www.istockphoto.com/video/male-fallow-deer-in-early-morning-in-the-mountain-gm455379664-47416706

• ambling, in the case of a 'sizing-up' rivalry:
  https://www.youtube.com/watch?v=5DuKpftCyYQ

Rucervus duvaucelii duvaucelii

semi cross-walking:

https://www.shutterstock.com/da/video/clip-9660908-barasingha-buck-male-adult-lone-walking-dry

https://www.shutterstock.com/da/video/clip-1102408671-full-shot-wild-barasingha-rucervus-duvaucelii-swamp

Rucervus duvaucelii branderi

semi cross-walking:

https://www.inaturalist.org/observations/203124378

https://www.inaturalist.org/observations/41095389

https://www.inaturalist.org/observations/167214

particularly clear illustration: https://www.youtube.com/watch?v=EBigKO906QY

Rucervus duvaucelii ranjitsinhi

semi cross-walking:

https://www.inaturalist.org/observations/151055042

https://www.inaturalist.org/observations/57116955

Rucervus eldii thamin

semi cross-walking:

https://www.inaturalist.org/observations/168242154

Rusa unicolor

semi cross-walking:

https://www.shutterstock.com/da/video/clip-1088508487-two-sambar-deer-walking-tall-grass-chitwan

https://elements.envato.com/beautiful-male-sambar-rusa-unicolor-deer-walking-i-7B59BYH

https://www.shutterstock.com/da/video/clip-1092275273-full-shot-alert-male-sambar-deer-rusa

https://www.shutterstock.com/da/video/clip-3408587259-wide-shot-wild-male-sambar-deer-rusa

https://www.shutterstock.com/da/video/clip-1086299906-medium-shot-alert-male-sambar-deer-rusa

https://www.shutterstock.com/da/video/clip-1088509085-sambar-deer-walking-tall-grass-chitwan-national

https://www.alamy.com/a-sambar-deer-walking-in-the-forest-of-kanha-national-park-madhya-pradesh-india-image353387093.html

https://www.shutterstock.com/da/video/clip-1061061169-sambar-deer-rusa-unicolor-walking-camping-site

nearly ambling:

https://www.shutterstock.com/da/video/clip-1044746029-beautiful-male-sambar-rusa-unicolor-deer-walking

https://www.shutterstock.com/da/video/clip-1043561428-male-sambar-rusa-unicolor-deer-walking-forest

Axis axis

semi cross-walking:

https://www.shutterstock.com/da/video/clip-1086407951-spotted-deer-walking-by-lake-grazing-on

https://www.shutterstock.com/da/video/clip-1106064753-young-fawn-walking-family-chital-deer-axis

https://www.alamy.com/stock-photo-spotted-deer-axis-axis-adult-male-walking-across-track-in-forest-pench-87949737.html

https://www.agefotostock.com/age/en/details-photo/chital-axis-axis-ram-walks-through-shrubland-wilpattu-national-park-sri-lanka/IBK-4636520

https://www.inaturalist.org/observations/200980388

https://www.inaturalist.org/observations/200949170

https://www.inaturalist.org/observations/198874750

https://www.inaturalist.org/observations/198017784

https://www.inaturalist.org/observations/195135338

https://www.inaturalist.org/observations/193248217

https://www.inaturalist.org/observations/190913332

https://www.inaturalist.org/observations/189221931

https://www.inaturalist.org/observations/180169624

https://www.inaturalist.org/observations/154401674

https://www.inaturalist.org/observations/146830355

https://www.inaturalist.org/observations/141066937

https://www.inaturalist.org/observations/128162956

https://www.inaturalist.org/observations/124302723

https://www.inaturalist.org/observations/121589144

https://www.inaturalist.org/observations/106209507

https://www.inaturalist.org/observations/104858657

https://www.inaturalist.org/observations/86792450

https://www.inaturalist.org/observations/84813634

https://www.inaturalist.org/observations/78527205

https://www.inaturalist.org/observations/67505176

https://www.inaturalist.org/observations/62016340

https://www.inaturalist.org/observations/58817487

https://www.inaturalist.org/observations/58494440

https://www.inaturalist.org/observations/52911280

https://www.inaturalist.org/observations/17745503

cross-walking while wading:

https://www.inaturalist.org/observations/103764392

https://www.inaturalist.org/observations/76480500

cross-walking on slippery mud:

https://www.inaturalist.org/observations/9286624

ambling when walking slowly and intermittently:

https://www.shutterstock.com/da/video/clip-1076048012-chital-axis-known-spotted-deer-walks-along

https://www.shutterstock.com/da/video/clip-1044612139-young-female-chital-spotted-deer-walking-fresh

Axis calamianensis

semi cross-walking:

https://www.pinterest.com.au/pin/axis-calamianensis-il-cervo-delle-calamian--532691462160335580/

Axis porcinus

semi cross-walking:

https://www.inaturalist.org/observations/200989109

cross-walking:

https://www.inaturalist.org/observations/204580149

https://www.inaturalist.org/observations/189105346

https://www.inaturalist.org/observations/171540300

https://www.inaturalist.org/observations/143331865

https://www.inaturalist.org/observations/143331862

https://www.inaturalist.org/observations/132290202

https://www.inaturalist.org/observations/104537477

https://www.inaturalist.org/observations/75619533

https://www.inaturalist.org/observations/56209847

Muntiacus muntjak

semi cross-walking:

https://www.youtube.com/watch?v=24TTA2hyACg

https://www.inaturalist.org/observations/199189534

https://www.inaturalist.org/observations/104055155

https://www.inaturalist.org/observations/50964329

Muntiacus reevesi

semi cross-walking:

https://www.inaturalist.org/observations/131640943

https://www.inaturalist.org/observations/189456815

https://www.inaturalist.org/observations/189456814

https://www.inaturalist.org/observations/189456818

https://www.inaturalist.org/observations/198193914

https://www.inaturalist.org/observations/153315798

https://www.inaturalist.org/observations/198125641

https://www.inaturalist.org/observations/159119168

https://www.inaturalist.org/observations/160588169

https://www.inaturalist.org/observations/175548019

https://www.inaturalist.org/observations/88361679

https://www.inaturalist.org/observations/194393858

https://www.inaturalist.org/observations/91085505

https://www.inaturalist.org/observations/160533132

https://www.pond5.com/stock-footage/item/171621770-muntjac-muntiacus-reevesi-6-walking-meadow-frosty-moning

https://www.youtube.com/watch?v=uOR-xWEDu-c

https://www.youtube.com/watch?v=hdY3V2gS9nE

https://www.inaturalist.org/observations/203805111

https://www.inaturalist.org/observations/200407447

https://www.inaturalist.org/observations/68049271

https://www.inaturalist.org/observations/37197028

https://www.inaturalist.org/observations/27135781

cross-walking:

https://www.inaturalist.org/observations/32206829

https://www.inaturalist.org/observations/202647340

https://www.inaturalist.org/observations/202100088

https://www.inaturalist.org/observations/191197301

https://www.inaturalist.org/observations/169551622

https://www.inaturalist.org/observations/69861331

https://www.inaturalist.org/observations/37197028

https://www.inaturalist.org/observations/36801722

Muntiacus vaginalis

semi cross-walking:

https://www.shutterstock.com/da/video/clip-1085402930-barking-deer-muntiacus-muntjak-female-walking-towards

https://www.dreamstime.com/muntjac-wandering-indian-forest-kanha-national-park-india-image178606716

https://www.dreamstime.com/indian-muntjac-muntiacus-muntjak-walking-road-khao-yai-national-park-thailand-indian-muntjac-road-image116200885

https://www.dreamstime.com/wild-brown-muntjac-walking-meadow-khao-yai-national-public-park-thailand-wild-brown-muntjac-walking-meadow-image129504847

https://www.inaturalist.org/observations/154108943

https://www.inaturalist.org/observations/113053895

https://www.inaturalist.org/observations/195042714

https://www.inaturalist.org/observations/194976263

https://www.inaturalist.org/observations/20352798

https://www.inaturalist.org/observations/180760250

https://www.inaturalist.org/observations/166776808

https://www.inaturalist.org/observations/158022968

https://www.inaturalist.org/observations/130205558

https://www.inaturalist.org/observations/31520508

https://www.inaturalist.org/observations/123318951

https://www.inaturalist.org/observations/93027063

https://www.inaturalist.org/observations/45948655

https://www.inaturalist.org/observations/35532310

cross-walking on stony (uneven) ground:

https://www.inaturalist.org/observations/127327396

https://www.inaturalist.org/observations/173583089

cross-walking on even ground:

https://www.inaturalist.org/observations/148684604

https://www.inaturalist.org/observations/146966105

https://www.inaturalist.org/observations/29632667

https://www.inaturalist.org/observations/131635371

https://www.inaturalist.org/observations/127111592

https://www.inaturalist.org/observations/123514259

https://www.inaturalist.org/observations/106431659

https://www.inaturalist.org/observations/105837724

https://www.inaturalist.org/observations/66402576

https://www.inaturalist.org/observations/66351601

https://www.inaturalist.org/observations/65449146

https://www.inaturalist.org/observations/63630513

https://www.inaturalist.org/observations/55674785

https://www.inaturalist.org/observations/55160054

https://www.inaturalist.org/observations/55159578

https://www.inaturalist.org/observations/50530419

https://www.inaturalist.org/observations/45470885

https://www.inaturalist.org/observations/44433993

to be continued in https://www.inaturalist.org/journal/milewski/91630-walking-gaits-in-cervidae-deer-tend-to-cross-walk-as-opposed-to-the-ambling-typical-of-many-bovids-part-2-odocoileinae#...