Which ungulates possess an ischial flag, in the sense of particularly conspicuous (advertisement) colouration on the buttocks?

Many ungulates have pale pelage, of various extents and shapes, on the buttocks (ischial surface, https://dictionary.cambridge.org/dictionary/english/ischial and https://www.merriam-webster.com/medical/ischial).

The following shows the location of the ischium, the posterior-most bone in the pelvic skeleton: https://afs.ca.uky.edu/livestock/dairy/skeletal

However, in this Post I exclude those cases in which the feature in question

extends to the rump or haunches (e.g. Alcelaphus: https://www.inaturalist.org/observations/103888817 and https://www.inaturalist.org/observations/128384280 and https://www.inaturalist.org/observations/37492988),
is less conspicuous than the tail (),
is hidden posturally under normal circumstances (e.g. Raphicerus campestris: https://www.inaturalist.org/journal/milewski/70293-the-bambis-part-9-bleezes-flags-and-semets-in-the-bovid-genus-raphicerus), and
is outweighed, in overall conspicuousness, by bold colouration elsewhere on the figure, including the tail (e.g. gazelles: https://internationalsportsman.com/blackbuck-antelope-small-in-stature-big-in-sport/ and https://www.naturepl.com/stock-photo-thomson-39-s-gazelle-eudorcas-thomsonii-female-and-calf-masai-mara-nature-image01622554.html and https://www.dreamstime.com/stock-photo-gazelle-thomson-to-eat-grass-masai-mara-national-park-kenya-image68396184).

In other words, I am particularly interested in those forms in which - at least in posteriolateral view - an ischial patch is the most conspicuous feature of colouration.

The following should serve for an approximate search-image: https://www.africaimagelibrary.com/-/galleries/east-africa/rwanda/-/medias/0253a725-2299-45bf-9a1e-8583be306b0a-defassa-waterbuck-kobus-ellipsiprymnus-defassa-akagera-natio.

The tail has particular potential as a complicating factor in the relative conspicuousness of the buttocks.

This is because the tail

is more mobile than the buttocks, hence more conspicuous in motion (https://www.grida.no/resources/2553),
can be raised and held high, defining the silhouette of the figure (https://www.inaturalist.org/observations/130903897 and https://www.inaturalist.org/posts/53340-differences-among-gazelles-in-the-structure-and-function-of-the-tail and https://www.inaturalist.org/journal/milewski/69548-caudal-flagging-in-thomson-s-gazelle-compared-with-the-goitered-gazelle),
if dark in contrast to pale buttocks, can be the more noticeable component of the composite pattern, even when stationary (https://www.projectnoah.org/spottings/1877256002/fullscreen and https://www.dreamstime.com/thomsons-gazelle-eudorcas-thomsonii-thomsons-gazelle-eudorcas-thomsonii-single-adult-young-kenya-september-image161979710 and https://www.gettyimages.com.au/detail/photo/pampas-deer-royalty-free-image/664344424?phrase=pampas+deer&adppopup=true and https://www.gettyimages.com.au/detail/photo/pampas-deer-royalty-free-image/664343890?phrase=pampas+deer&adppopup=true and https://www.facebook.com/watch/?v=953730318399390),
..

Gazella arabicahttps://www.pixoto.com/images-photography/animals/other-mammals/arabian-gazelle--6523769179602944

Gazella bennettiihttps://www.alamy.com/wild-chinkara-gazella-bennettii-aka-indian-gazelle-in-grasslands-habitat-around-pune-maharashtra-india-image224965292.htmlhttps://www.shutterstock.com/image-photo/chinkara-gazella-bennettii-grasslands-2282460153https://www.shutterstock.com/image-photo/chinkara-gazella-bennettii-grasslands-2282490895

Gazella maricahttps://www.flickr.com/photos/mikebarth/23973307372https://arabsstock.com/en/photos/image-79510-al-reem-gazelle-animal-one-nature-reserves-united-arab-emirates https://www.dreamstime.com/group-gazelles-group-beautiful-young-sand-gazelles-gazella-marica-park-arabian-peninsula-image193473128

Hippotragus niger

https://www.sciencephoto.com/media/389584/view/sable-antelope
https://www.agefotostock.com/age/en/details-photo/female-sable-antelope-hippotragus-niger-in-natural-habitat-south-africa/ESY-032086305
https://www.inaturalist.org/observations/180600325
https://www.inaturalist.org/journal/milewski/88983-does-the-sable-antelope-hippotragus-niger-possess-a-bleeze-part-1#
https://www.inaturalist.org/posts/85930-does-the-sable-antelope-hippotragus-niger-possess-a-bleeze-part-2-sexual-and-ontogenetic-development-of-the-ischio-abdominal-pattern-in-the-southern-sable-antelope-h-n-niger#
https://www.inaturalist.org/journal/milewski/86047-does-the-sable-antelope-hippotragus-niger-possess-a-caudal-flag#

Kobus defassa

This is perhaps the clearest-cut example of an ischial flag, among all the ungulates. However, even in this case, there is a compromising consideration. This is that Kobus ellipsiprymnus, which is often considered a subspecies of K. defassa, has a categorically different pattern on the hindquarters. Furthermore, the whitish pelage extends ventrally on to the upper hindlegs.

https://www.sciencephoto.com/media/389729/view/defassa-waterbuck
https://www.shutterstock.com/image-photo/defassa-waterbuck-looks-back-across-masai-2059418618
scroll in http://www.wildlife-of-africa.com/animals/defassa-waterbuck.htm

Gazella bennettii
https://www.shutterstock.com/image-photo/chinkara-gazella-bennettii-grasslands-2282490895

Antilope cervicapra

https://www.mediastorehouse.com.au/nature-picture-library/yashpal-rathore/blackbuck-antelope-cervicapra-male-18204719.html
https://www.dreamstime.com/black-buck-kid-portrait-green-back-ground-bucks-resident-species-gujarat-india-found-many-places-big-groups-image184881130

Ourebia ourebi

https://www.inaturalist.org/posts/70005-are-there-two-species-of-oribi-ourebia-instead-of-one#
https://www.inaturalist.org/posts/69937-adaptive-colouration-in-the-oribi-southern-forms-are-more-conspicuous-than-northern-forms#
https://www.inaturalist.org/posts/70860-summary-of-my-recent-observations-diagnostically-pale-features-on-the-hindquarters-of-bovid-bambis-ourebia-raphicerus-and-madoqua#
https://colombia.inaturalist.org/journal/milewski/70050-the-three-main-types-of-oribi-ourebia-at-a-glance#

Aepyceros melampus

Bos javanicus

The banteng (Bos javanicus) is the only member of the subfamily Bovinae that possesses an ischial flag.

This feature is somewhat sexually dimorphic. It is most distinct in mature males.

Dama dama

DISCUSSION

I know of no ungulate in which the buttocks are the only part of the stationary figure with conspicuous colouration.

There is no species of ungulate in which the conspicuous colouration on the buttocks constitutes, in itself, a bleeze.

This is because a bleeze is, by definition, more conspicuous than a flag. The buttocks are

a medium-size, not large, surface,
hardly visible in full profile, and
not as well-illuminated as the rump.

Bleezes on the hindquarters often include the buttocks, but are never restricted to the buttocks.

https://www.istockphoto.com/photo/white-tailed-deer-gm1180023691-330423556?phrase=white+tailed+deer+tail&searchscope=image%2Cfilm

The flag of Capreolus capreolus in winter pelage straddles the boundary between the buttocks and the rump (https://www.dreamstime.com/roe-deer-winter-scenery-roe-deer-winter-forest-scenery-image237055449 and https://www.shutterstock.com/image-photo/roe-deer-winter-1585340431).

Cervus elaphus exemplifies the same principle, differing only in detail.
https://www.alamy.com/male-red-deer-stag-in-old-forest-from-back-view-looking-aside-image355584145.html

In the case of Cervus nippon, the main part of the conspicuous feature is indeed on the buttocks, but there is a significant extension on to the base of a tail that is so short that a caudal flag is out of the question.
https://fishandhuntmaryland.com/articles/pursuit-sika-deer
https://www.bing.com/images/search?view=detailV2&ccid=GCxZg9PV&id=081BF38D6DFAFF42D916D52C9FD5D8A61A31ECC0&thid=OIP.GCxZg9PVcy6uGsfU0rQ8NAHaFK&mediaurl=https%3A%2F%2Fwww.wildlifeonline.me.uk%2Fassets%2Fugc%2Fimages%2Fsika_stag_speed.jpg&exph=845&expw=1212&q=sika+deer&simid=608050370566253003&form=IRPRST&ck=76A9FB41D31CB5D328E75D346DB99DB3&selectedindex=3&itb=0&ajaxhist=0&ajaxserp=0&vt=0&sim=11
https://bestpracticeguides.org.uk/deer-ecology/sika-deer/

Posted on January 24, 2024 10:17 PM by

milewski

Which ungulates possess an ischial flag, in the sense of particularly conspicuous (advertisement) colouration on the buttocks?

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