Field-notes from an excursion with the dromedary (Camelus dromedarius), northern Kenya, 1990-1991

@fragmansapir @waswala @zarek @davidbygott @dejong @wasinitourguide @michalsloviak @oumarouhamadou @tonyrebelo @jeremygilmore @botswanabugs @matthewinabinett

From 22 December 1990 to 1 January 1991, I took part in an 8-day walking 'camel-safari', along the Milgis River (https://navigatekenya.wordpress.com/2015/06/18/river-milgis/ and https://www.alamy.com/stock-photo/kenya-milgis-river-samburu.html?sortBy=relevant) in northern Kenya (similar to https://bushsnob.com/tag/milgis-river/ and https://www.samburureserve.com/camel-trekking-safari-samburu.php).

The route was approximately from Ilaut-Ngurnit to Siambu (https://www.mindat.org/feature-196514.html and https://www.google.com.au/maps/place/Ngurunit,+Kenya/@1.7375958,37.2663988,14z/data=!4m6!3m5!1s0x178ff57c4d04ba1d:0xf89922c8fd5642a!8m2!3d1.7298799!4d37.3078999!16s%2Fg%2F11h1f57lv and https://www.mindat.org/feature-11671008.html).

Today, I dusted off my yellowing field notes from this trip.

The five individuals of the dromedary (Camelus dromedarius), which carried our tents and provisions, were castrated adult males, of body mass probably less than 400 kg.

VEGETATION

The vegetation on the foothills of the Ndoto range is acacia-Commiphora scrub, with plentiful Grewia and various other genera, and an understorey consisting mainly of 'karoid' shrubs.

The vegetation in the vicinity of the Milgis River (https://www.alamy.com/stock-photo-kenya-barsaloi-milgis-the-milgis-lugga-a-somali-word-meaning-a-seasonal-19159671.html) and Ndoto range was rich in lianes, but not particularly rich in mistletoes.

The vegetation was fully green, this excursion being at the end of the green season proper. Even Commiphora, which is green only for a short period each year, was in full foliage at the time.

The fruiting season was in full swing. The fruits (pods) of the acacias were at the green, growing stage. Vachellia tortilis (https://www.inaturalist.org/taxa/489563-Vachellia-tortilis) was in full fruit.

I found it remarkable how little grass occurred hereabouts. The vegetation is technically savanna. However, the lower stratum consists not of grass but of small-leafed shrubs.

I observed Croton megalocarpus (https://www.inaturalist.org/taxa/133588-Croton-megalocarpus) only near Maralal. Local persons told me that when this species starts to flower, the rains are over - a reliable sign.

Cistanche tubulosa (https://www.inaturalist.org/taxa/49562-Cistanche-tubulosa) was in flower at the time. I found specimens of this herbaceous plant, excavated by some animal, perhaps Papio anubis.

UNGULATE FAUNA

The common wild ungulates seemed to be Litocranius walleri and Madoqua guentheri (https://www.inaturalist.org/taxa/42359-Madoqua-guentheri).

Strepsiceros strepsiceros chora (https://www.inaturalist.org/observations/150587246) occurred in the hills. There were sparse populations of Oryx beisa beisa (https://www.inaturalist.org/observations?taxon_id=147720), Syncerus caffer, and Giraffa reticulata.

FORAGING METHODS OF DROMEDARY

I observed the dromedary rapidly taking large mouthfuls of various greens palatable to it. However, it was evident that it does not forage indiscriminately, with regard to either physical or chemical defences.

I particularly observed the dromedary stripping Cordia sinensis (which lacks spines), defoliating lengths of branch up to 1 m long with each stroke of the mouth.

It seemed to me that spines were an effective defence against the dromedary, despite the reputation of this ungulate for being able to chew spines. This was because I watched the dromedary foraging on acacias, in a way more tentative and complex than I have described above for C. sinensis.

'POISON-ARROW TREE'

I encountered Acokanthera schimperi (https://www.inaturalist.org/taxa/888341-Acokanthera-schimperi and https://tropical.theferns.info/viewtropical.php?id=Acokanthera+schimperi and https://royalsocietypublishing.org/doi/10.1098/rspl.1895.0009 and https://apps.worldagroforestry.org/usefultrees/pdflib/Acokanthera_schimperi_ETH.pdf) in Yare campsite in Maralal (https://en.wikipedia.org/wiki/Maralal).

This small tree/large shrub (https://twitter.com/UofUNews/status/1329949467945037824) was dotted conspicuously on the hills around the town. It had obviously been left by wood-cutters. The reason given by our guide was that even the wood-smoke of this toxic plant is harmful to human eyes.

The foliage is evergreen and somewhat sclerophyllous, despite an association with nutrient-rich soils.

The specimens in Yare campsite were in flower and unripe fleshy fruit, on Christmas day of 1990.

It seems somewhat paradoxical that Loxodonta africana reputedly consumes both the fruits and the foliage avidly, given that Acokanthera schimperi is extremely defended against herbivory. I suspect that this plant is also eaten by Giraffa reticulata.

The anti-herbivore defences are

• latex, which I found only in the unripe fruits, the developing pulp of which was extremely rubbery,
• cardenolides (cardiac glycosides) in the sap, and (presumably) alkaloids in the leaves (https://link.springer.com/chapter/10.1007/978-1-4757-2905-4_3),
• prickles, which were absent from the inadvertently protected specimens in this fenced campsite,
• (presumably) tannin, as indicated by the reddish hue of the shoots),
• fibre (which confers a somewhat leathery texture to the leaves), and
• (presumably) vegetative regeneration from the base, after gross damage.

I slashed the bark (which seems fire-resistant), revealing an innocuous creamy colour.

Despite the toxicity of the plant, its ripe fruits (with an orange hue) were reported by our guide, Kiberiti, to be wholesome for human consumption.

This family (Apocynaceae) seems to specialise in extreme antiherbivore defence (https://www.sciencedirect.com/science/article/abs/pii/037887419390065D), as indicated by the fact that confamilial Carissa is one of the few spinescent species of sclerophyllous plants in the fynbos biome of South Africa (https://www.inaturalist.org/observations/158859102).

On one specimen in Yare campsite, I observed a species of mistletoe, with small, 'penny-shaped' leaves, and orange-hued fleshy fruits. There seemed to be some mimicry between the parasite and the host in the size and shape of the leaves, and the hue of the ripe fruits; however, the fruits of the mistletoe were noticeably smaller (6 X 3 mm) than those of A. schimperi (7 X 7 mm).

DETAILS OF ANATOMY OF DROMEDARY

HEAD:

The dromedary tends to keep the rostrum as the highest point on the body, as if keeping a life-bubble aloft.

The eyelashes are dense, but fairly short (https://www.cameltracks.com/camel-facts/).

The nictitating membrane (https://en.wikipedia.org/wiki/Nictitating_membrane) is used visibly in 'deep blinks'. However, after dissecting this membrane in various species of ungulates, I did not find it to be particularly well-developed in the dromedary.

The dorsal flap of the iris has the appearance of a complex awning (https://i.redd.it/v10ararifcr61.jpg and https://i.redd.it/rkcnrhoh5x261.jpg). The whole iris, including this 'awning-flap' is brown. In bright daylight, the horizontal slit-pupil becomes so narrow that the folds of the 'awning' virtually touch the ventral border of the pupil (https://fineartamerica.com/featured/camels-eye-mekh-paija.html).

As in Giraffa (https://www.dreamstime.com/giraffe-giraffa-genus-african-even-toed-ungulate-mammals-tallest-living-terrestrial-animals-largest-ruminants-face-image151609904 and https://www.stockfreeimages.com/6716067/Giraffe-face.html),

• the orbits of the dromedary are wide-set (https://www.istockphoto.com/photo/curious-camel-in-desert-gm1070151038-286303665?phrase=camel+face and https://www.istockphoto.com/photo/picture-of-a-camels-face-on-a-white-background-gm157283338-885268?phrase=camel+face), which is presumably adaptive to all-round visual scanning in open environments, and
• the eyes are somewhat downward-oriented, facilitating vision of the area below the head (https://www.redbubble.com/people/hilbert72/works/39157330-giraffe-head-viewed-from-below and https://www.shutterstock.com/it/image-photo/giraffe-head-below-1127011748 and https://www.alamy.com/underside-of-giraffe-s-head-image4446609.html and https://www.shutterstock.com/it/image-photo/camel-head-neck-below-587377079 and https://www.dreamstime.com/portrait-camel-against-blue-sky-view-below-head-looking-camera-background-clear-image189161105).

However, in the dromedary the proportional size of the eyeballs is fairly small (https://es.123rf.com/photo_25953768_a-close-up-profile-view-of-an-arabian-camel-also-known-as-camelus-dromedarius-the-dromedary-is-a-lar.html and https://depositphotos.com/253365696/stock-photo-a-close-up-of-the.html), in contrast to the extremely large eyeballs of Giraffa (https://unsplash.com/photos/6341uLtNHV8).

In Giraffa, orbital configuration and eye-size are congruent, whereas in the dromedary they seem incongruent. This can perhaps be explained by the eyes of the dromedary being adapted mainly for reducing the brightness of sunlight, and the eyes of Giraffa being adapted mainly for maximising vision at night.

The tongue is pink. I did not observe any extension of the tongue during foraging. In this way, the dromedary is categorically different from Giraffa.

The ear pinnae of the dromedary are less mobile than those of true ruminants. They are hairier than in most ruminants, particularly on the anterior surface (https://www.dreamstime.com/ear-camel-ear-camel-park-nature-image105982639 and https://www.alamy.com/closeup-of-a-camel-face-eye-and-ear-image348148951.html).

The nares are valvular by means of the lower (ventral), not upper (dorsal) flap.

I never observed the dromedary to snort. However, I did observe it to sneeze.

The dromedary possesses vibrissae on the lips, cleft philtrum, and anterior surface of the nares (https://www.dreamstime.com/stock-photo-camel-muzzle-what-looks-like-smug-mouth-image51758280 and https://fineartamerica.com/featured/camels-mouth-mekh-paija.html and https://www.alamy.com/close-up-on-the-snout-of-a-camel-with-furry-whiskers-image207256836.html?imageid=E1F23F0D-0DC8-4B87-B93B-BA79215DC893&p=687389&pn=1&searchId=4bd10d2555febc8b8849056b8700d23f&searchtype=0 and https://www.alamy.com/close-up-photo-image-of-bactrian-camels-snout-image265612291.html?imageid=7047E2DF-FBD2-4B77-9FA5-E138DEC2DB0B&p=174910&pn=1&searchId=4bd10d2555febc8b8849056b8700d23f&searchtype=0). Those on the lips seem more prominent than in Giraffa, and more like those of Carnivora.

However, there are no vibrissae on the cheeks.

The vibrissae around the eyes, including the lower eyelid and its vicinity, are long. There are also vibrissae on the eyebrow-pads and -tufts.

There are also short vibrissae on

• the ventral surface of the mandibles, and
• the crown of the head.

The enamel and dentine of the anterior lower incisors (https://www.gettyimages.co.uk/detail/photo/camel-looking-down-at-camera-royalty-free-image/1144004941?phrase=camel+teeth&adppopup=true) is worn into grooves, by habitual stripping of foliage off woody stems.

NECK:

I observed the dromedary resting its head on the ground, while lying in sternal recumbency (https://www.shutterstock.com/it/image-photo/camel-lying-down-sahara-desert-outside-2285341661).

The dromedary seems to have glandular tufts of hair on the nape of the neck (https://www.shutterstock.com/it/image-photo/back-view-camel-doha-qatar-405597601 and https://www.shutterstock.com/it/image-photo/close-brown-camel-head-neck-behind-1200247813 and https://www.alamy.com/proud-dromedary-camel-head-camelus-dromedarius-in-profile-close-up-11-square-photo-blue-sky-in-the-background-image435403051.html and https://www.dreamstime.com/single-hump-camel-head-neck-arabian-image195683691).

The dromedary possesses a minimal mane.

Our specimens (castrated males) completely lacked any beard.

The dorsal skin of the neck is wrinkled, in normal postures.

There are strange paired bumps at the crook-of-throat and the junction between neck and chest.

TORSO:

There is a mane on the hump. This seems to wear down, and become pale, with age.

The pelage was short and slightly glossy, but contained scattered, dark bristles.

When the dromedary lies down in sternal procumbency (https://es.123rf.com/photo_93685730_picturesque-desert-dromedary-camel-lying-on-sand-summer-sahara-travel-and-tourism-blue-sky-and-beaut.html and https://www.istockphoto.com/photo/profile-camel-isolated-on-white-gm941615320-257358913), its body is kept off the ground by a total of nine callosities (brisket, carpals, elbows, knees, and hocks).

In sternal recumbency, the figure of the dromedary, unlike that of giraffes (https://www.alamy.com/giraffe-lying-down-on-the-ground-image333464081.html), is symmetrical.

The callosity on the brisket is mounted on a cartilaginous pedestal (https://www.shutterstock.com/it/image-photo/camel-lying-down-mud-puddle-keep-2193242189 and scroll to fourth photo in https://petkeen.com/how-do-camels-sleep/).

The torso of the dromedary has a somewhat conical shape, with the larger end anterior. The withers are higher than the rump, and the abdomen is remarkably slim (https://eustat.files.wordpress.com/2015/06/wpid-wp-1433392947148.jpg), tending to have a concave rather than convex ventral silhouette. The 'conical' configuration is easily overlooked, owing to the distraction of the hump.

There is a prominent vein on the lower flank (https://www.shutterstock.com/it/image-photo/dromedary-camel-baby-standing-together-on-2267890529 and https://www.alamy.com/camel-standing-on-the-sand-dune-in-the-dry-desert-dubai-united-arab-image66569195.html?imageid=A1ABC516-BACD-4D8C-BD4A-8B3924518E6C&p=143110&pn=1&searchId=440721b61087ec200c30474f20054454&searchtype=0).

I observed the dromedary rolling on to its side, to dust-bathe.

I noticed that the breathing of the dromedary, while standing, was audible.

The penis is reflexed (https://www.youtube.com/watch?v=SXuk4GEHxeQ), facilitating the deposition of urine on the tail. The prepuce forms a skin-flap, similar to a dewlap.

LIMBS:

The dromedary is able to stand for long periods on three legs (https://www.alamy.com/stock-photo-tied-up-camel-at-the-dunes-morocco-174732472.html?imageid=0786853F-E516-4953-BBF8-4A3F6FC6FDCA&p=174269&pn=1&searchId=7d4be4c250fe37c4f3608eed9191f4c9&searchtype=0 and https://www.alamy.com/stock-photo-dromedary-camel-with-one-front-leg-tied-up-underneath-itself-to-stop-32029363.html?imageid=4D1FA54C-A1B1-4563-B76A-5CA6E9F10935&p=80640&pn=1&searchId=7d4be4c250fe37c4f3608eed9191f4c9&searchtype=0 and https://www.alamy.com/dromedary-camels-hoof-detail-camel-with-a-tied-foot-in-sahara-desert-animal-theme-image452559334.html?imageid=6FEE497A-F5F0-43D9-90DF-9F74C7FB13FB&p=217933&pn=1&searchId=7d4be4c250fe37c4f3608eed9191f4c9&searchtype=0). It compensates by splaying the hind legs, in aid of stability.

The carpal (https://www.gettyimages.in/detail/photo/man-fettered-feet-of-a-camel-to-not-escape-royalty-free-image/179409649?adppopup=true) and tarsal joints are extremely flexible, which facilitates the use of the legs in shooing flies off the torso by lifting one leg at a time.

The flexibility of the hocks (tarsal joint) is particularly odd, which is most evident in sternal recumbency (https://www.shutterstock.com/it/image-photo/white-dromedary-lying-down-dry-sunny-2236777003).

The following show the tracks of the dromedary (https://www.alamy.com/camel-tracks-camelus-dromedarius-in-the-great-victoria-desert-western-australia-image207033348.html and https://www.alamy.com/bactrian-camel-tracks-in-the-sand-at-the-hongoryn-els-sand-dunes-in-the-gobi-desert-in-southern-mongolia-image344080905.html and flip in https://www.mpalalive.org/field_guide/view/camel).

The nails of the hooves do not touch the ground, in normal standing on hard surfaces (https://www.gettyimages.in/detail/photo/camels-hoof-close-up-royalty-free-image/1069841060?adppopup=true).

TAIL:

The tail of the dromedary reaches to just below the level of the callosity on the knee.

It has lateral (left and right) rows of long hairs, extending right to the base (https://stock.adobe.com/bg/images/closeup-of-the-camel-s-tail-protects-the-insects/571850846 and https://klrajaponsing.wordpress.com/2014/11/16/camels-are-beautiful-and-graceful/tail-me-not/ and https://www.alamy.com/stock-photo-camels-tail-170460911.html?imageid=7CCEDB13-BDEC-4074-AAE1-BFF549F9E39A&p=184625&pn=1&searchId=e6d93066a5ff80b692b7196a1e7cb031&searchtype=0 and https://www.shutterstock.com/it/image-photo/camel-tail-close-united-arab-emirates-1319362250).

The tail has a rudimentary tassel, consisting of the prolongation of the lateral and dorsal rows of long hairs on the tail-stalk.

The tail is raised as a sign of indignation, accompanied by an open-mouthed grunt/squeal/bellow.

GAITS

(Also see https://www.inaturalist.org/posts/92119-impalas-aepyceros-and-giraffes-giraffes-share-the-same-walking-gait-namely-an-amble#activity_comment_75055581-fab2-4eac-a2d4-83f883467ae3 and https://www.inaturalist.org/journal/milewski/85161-variation-in-walking-gaits-in-ungulates-why-some-hoofed-mammals-cross-walk-whereas-others-amble#.)

The dromedary has a reputation of walking in an odd way (https://zslpublications.onlinelibrary.wiley.com/doi/abs/10.1111/j.1469-7998.1974.tb03144.x and https://hqmagazine.co.za/walking-like-a-camel-the-lateral-walk/ and https://thedailywildlife.com/camel-walk/).

However, after scrutinising various ungulates during this walk, I realised that the walking gaits of C. dromedarius, Giraffa reticulata, Equus asinus, Bos indicus/taurus, and Capra hircus all lie on a continuum, with no sharp distinctions. The dromedary resembles Giraffa, in that it usually ambles (see https://www.inaturalist.org/posts/85161-variation-in-walking-gaits-in-ungulates-why-some-hoofed-mammals-cross-walk-whereas-others-amble#). The other spp. have walking gaits intermediate between an amble and a cross-walk.

One way to describe the walking gaits of C. dromedarius, G. reticulata, E. asinus, and B. indicus/taurus, and probably also C. hircus (which steps so rapidly that I found it hard to keep track of the movements of the limbs) is as follows:

The walking gait in E. asinus and B. indicus/taurus is basically one foot at a time (https://www.researchgate.net/figure/Normal-walking-pattern-of-a-goat-and-its-support-graph-showing-periods-of-ipsilateral-and_fig5_11410222), which sounds like 'clip-clop-clip-clop'.

The hind left leaves the ground just as the fore right touches the ground, and then touches the ground just as the fore left leaves the ground; the fore left then touches the ground just as the hind right leaves it.

However, in G. reticulata and (usually) C. dromedarius, the hind foot overshoots (= 'oversteps') the track of the fore foot on the same side, bringing a risk of collision/obstruction. The hind foot of C. dromedarius is not placed in the same track as the preceding fore foot. It also cannot be placed to the outside of the fore, because of the slightly knock-kneed configuration of the legs of this species (which presumably confers stability).

Thus, the hind displaces the fore well before it swings in to land. As a result, the order of movement, instead of 'one foot at a time', is better-described as 'both left feet, followed by both right feet'.

Please see https://www.shutterstock.com/it/video/clip-1067425-camel-walking---slow-motion and https://www.google.com.au/search?q=giraffe+walking&sxsrf=APwXEdcBKJ1YLcWJGuY_iZnYs1AbjQ-y2g%3A1683195872517&ei=4IdTZMmUH7jn4-EPw_mvoAM&ved=0ahUKEwjJhMagudv-AhW48zgGHcP8CzQQ4dUDCA8&uact=5&oq=giraffe+walking&gs_lcp=Cgxnd3Mtd2l6LXNlcnAQAzIICC4QigUQkQIyBggAEAcQHjIGCAAQBxAeMgYIABAHEB4yBggAEAcQHjIGCAAQBxAeMgYIABAHEB4yCggAEAcQHhAPEAoyBQgAEIAEMgUIABCABDoKCAAQRxDWBBCwAzoKCAAQigUQsAMQQzoNCAAQ5AIQ1gQQsAMYAToSCC4QigUQ1AIQyAMQsAMQQxgCOgoIABCKBRCxAxBDOgcIABCKBRBDOgoILhCKBRCxAxBDOg4ILhCKBRDHARCvARCRAjoHCAAQDRCABEoECEEYAFCnEFi3KGDmL2gCcAF4AIAB_wGIAboUkgEGMC4yLjEwmAEAoAEByAETwAEB2gEGCAEQARgJ2gEGCAIQARgI&sclient=gws-wiz-serp#fpstate=ive&vld=cid:c53ca401,vid:Vh2yveXTKaU.

The difference is that, in G. reticulata and (usually) C. dromedarius, the overshoot (= 'overstep') is so extensive that the hind foot lands well ahead of where the front foot was planted. In the case of the dromedary, I found this to be >46 cm ahead.

In E. asinus and B. indicus/taurus, the hind foot plants itself on the spot of the fore foot.

Camelus dromedarius gives the impression of walking oddly, because its walking gait is usually an amble, as in the much longer-legged G. reticulata.

When C. dromedarius is on steep or slippery ground, it maintains its basic gait but simply shortens its stride, so that the hind foot does not overshoot (= 'overstep') the track of the fore foot.

Camelus dromedarius strides at >1.5-fold the frequency of a man walking at the same speed - in my case about 1.5, for shorter-legged persons somewhat more.

If you plant your left foot the same moment as C dromedarius does, the camel next plants the same left foot at the moment you take your left-right-left-RIGHT, i.e. 1.5-fold your stride cycle.

When B. indicus/taurus steps, its hind foot is placed in, or slightly behind, the track of the fore foot. The same applies to C. hircus and E. asinus.

I recorded that, when C. dromedarius steps, its hind foot passed the track of the fore foot by up to 60 cm, to land 1-3 hoof-widths behind the level of its opposite fore member. It did not reach that level, although it did pass the track of the fore foot on its own side.

The shortfall is less than this, in the case of Giraffa (https://www.youtube.com/watch?v=O2DC6fPFpw0).

STRIDE LENGTH

While walking at the same speed as C. dromedarius, my stride length was about 180 cm (my hip-height is 93 cm, whereas a woman in our group, 170 cm high, had hip-height of 90 cm). So, the stride of C. dromedarius seems to be >1.5-fold longer than that of a human. This seems to correspond with the difference in stride-frequency between dromedary and human.

The stride length of C. dromedarius was about 195 cm (hip-height 150 cm). The stride-length of B. indicus/taurus (small-bodied breed) was about 115 cm.

EXTREME TRACK PATTERN OF GIRAFFA RETICULATA

When Giraffa reticulata steps, the hind hoof can actually reach the level of the opposite fore hoof, in extreme cases being planted to the side of it (while the fore hoof is still there).

The result is that the tracks of Giraffa reticulata can form a deceptively simple, paired pattern.

During this walk, I recorded tracks of G. reticulata that looked almost as if the animal had hopped forward like a kangaroo. The tracks were arranged as a series of pairs.

Imagine a series of three such consecutive pairs, made by what I assumed to be an adult female.

Fore can be distinguished from hind, because its track is considerably the larger.

The first pair consists of hind on the left, and fore on the right. The second consists of fore on the left and hind on the right. The third replicates the pattern in the first.

I measured the distance between the pairs, and found it to be about 138 cm. The range of values was 135-140 cm.

Normal walking in Giraffa does not show this stride pattern (https://www.alamy.com/herd-of-giraffes-giraffe-family-image436174456.html?imageid=8CB11301-237B-4B11-8BDD-9A76B0FE87AF&p=475128&pn=2&searchId=86b4f3e85cd591c3e1b92ef9617c33a0&searchtype=0 and https://www.alamy.com/stock-photo-giraffe-herd-giraffa-camelopardalis-at-a-waterhole-etosha-national-92896929.html?imageid=09388849-61E5-489F-848F-9E0EAFBC2696&p=70019&pn=1&searchId=c3799bf6d46c7c01df763deac3e82cec&searchtype=0 and https://www.alamy.com/stock-photo-giraffe-walking-on-the-plains-in-the-wilds-of-africa-118777082.html?imageid=C11F5066-CEA5-4D30-990E-2580B30F6CCA&p=1428998&pn=1&searchId=c3799bf6d46c7c01df763deac3e82cec&searchtype=0).

Therefore, I infer that the paired tracks I observed were made

• by adult females, walking at maximum speed, or
• by adolescent males (which probably have proportionately long legs, compared to their mothers), walking at normal speed.

Both possibilities seem in evidence in the following photos (https://www.alamy.com/stock-photo/giraffe-herd.html?sortBy=relevant and https://www.gettyimages.com.au/detail/photo/masai-giraffe-herd-at-wild-royalty-free-image/1317677175 and https://www.alamy.com/stock-photo-giraffes-in-the-kaokoveld-namibia-africa-89970421.html?imageid=8192AA7A-FD03-47D3-BD6E-DA576035BFD0&p=83260&pn=1&searchId=c3799bf6d46c7c01df763deac3e82cec&searchtype=0), in which the hind hoof can be seen to reach level with the opposite fore hoof.

WATER ECONOMY OF THE DROMEDARY

Under cool conditions, the dromedary spreads its legs to micturate, the urine emerging in a dribbling way (https://www.istockphoto.com/tr/foto%C4%9Fraf/urinating-camel-gm184328150-17391681). Under hot conditions, it micturates on its hind legs, where the subsequent evaporation helps in thermoregulation (https://www.youtube.com/watch?v=Q1ohi5klY8A).

All five castrated male individuals, with which we walked, habitually splashed their urine on their rumps by means of the tail. I observed micturition to be a messy, splashy, drawn-out dribble, soiling the lower hind limbs.

Camelus dromedarius can be extremely economical with water, partly because it can thoroughly extract water from its feces. Picking up fresh fecal pellets, I was struck with how light they were for their size.

However, C. dromedarius does not emulate true ruminants in the extreme diminution of the fecal pellets.

Because of the ratio of surface area to volume, it makes obvious sense for the fecal pellets to be as small as possible, to facilitate thorough extraction of water in the terminal section of the colon.

However, the fecal pellets of C. dromedarius were surprisingly large.

This is presumably because the dromedary does not grind its food as thoroughly as like-size ruminants do.

The pellets were larger, and coarser-grained, than those of Giraffa reticulata, despite the larger body of the latter.

I was also surprised to find that the size and shape of the fecal pellets of the dromedary was variable. At the start of our excursion, the feces were only loosely formed; over subsequent days they became drier, darker, and clearly formed into pellets.

I am familiar with the shape of the fecal pellets of Oryx beisa callotis and Kobus ellipsiprymnus. I found the pellets of the dromedary, at least when the animal was well-hydrated, to resemble those of the latter, not the former, in shape. This is somewhat surprising, because Oryx resembles the dromedary in adaptation to aridity, whereas Kobus is particularly water-dependent.

The following are the dimensions (length X breadth in cm) of a sample of ten mucous-coated pellets that I measured, about halfway through this excursion. I estimated that their water-content was about 55% at the time of defecation.

2.2 X 2

3 X 1.5

2.3 X 1.4

2 X 1.4

3 X 1.4

3.4 X 1.5

1.5 X 1.3

1.5 X 2.1

1.5 X 1.9 (which is at the small end of the range)

2.8 X 2.0 (which is at the large end of the range)

I had an impression that not only the water-content but also the size of the pellets waned somewhat with increasing dehydration of the camel. However, this remains to be tested.

Even the dromedary has soft, moist fecal pellets when green food is abundant. One individual, with which we walked, even had diarrhoea. However, I noticed that, even when the feces were moist, the urine of the dromedary was still yellowish, rather than clear.

SEED-DISPERSAL OF CORDIA SINENSIS BY PAPIO ANUBIS

Cordia sinensis (https://www.inaturalist.org/taxa/342742-Cordia-sinensis) was in full fruit at this time, when the vegetation was fully green.

The ripe fruits (https://www.inaturalist.org/observations/34676524) are edible to both humans and Papio anubis (https://www.inaturalist.org/taxa/74832-Papio-anubis). However, the fruit-pulp is remarkably mucilaginous, and convergent in this way with the fleshy fruit-pulp of mistletoes.

Since C. sinensis is not parasitic, I assume that the mucilage helps its seeds, deposited on branches by birds, to stay safe until rain washes them to the ground to germinate.

The feces of P. anubis, which I encountered along the Milgis River, were in places soft and half-digested - a matrix of mushy greenish (leaves?), studded thickly with the still-red, and intact to partly broken down, fruits of C. sinensis. I assume that the seeds in these fruits were intact and viable.

This showed how superficial the digestion of P. anubis can be at times (particularly when eating fleshy fruits), and how little this monkey chews certain foods.

It is unsurprising that the 'snotty', gummy fruit-pulp of C. sinensis is swallowed whole rather than being chewed. However, I do not know whether the carbohydrate in the fruit-pulp can be extracted by the gut without chewing.

Either way, it seems certain that P. anubis is a major agent of dispersal of C. sinensis.

Papio anubis tends to deposit its feces on 'perches' in the form of boulders or logs. Does the gumminess of the fruit-pulp tend to attach the seeds for a while on these high surfaces?

A NON-INDIGENOUS DAISY

I found only one common daisy on gneiss and sand, in and near the Ndoto range (https://www.youtube.com/watch?v=quejK1EhznM and https://thekenyancamper.com/2016/05/26/ndoto-mountains-samburu-marsabit-kenya/ and https://www.youtube.com/watch?v=iIHbSyc5bl4 and https://www.youtube.com/watch?v=LHM0FmjB1uM).

This was an annual, Acanthospermun hispidum (https://www.inaturalist.org/taxa/157911-Acanthospermum-hispidum and https://keyserver.lucidcentral.org/weeds/data/media/Html/acanthospermum_hispidum.htm), which is not indigenous to Africa.

Acanthospermum hispidum was common on sheet-washed floodplains, where it grew in dense populations in places along the Milgis River and among the hills of the Ndoto range.

This daisy has a burr-fruit (https://www.researchgate.net/figure/Bristly-starbur-Acanthospermum-hispidum-seed-from-Georgia-Photograph-by-Sidney-Cromer_fig1_276113846), which clings efficiently. The species is presumably adapted to trampled, overstocked rangelands, being dispersed by large mammals.

I tasted the leaves, which are hairy on both the upper and the lower surfaces. I found them to have a strange combination of sweet and bitter. They are obviously well-defended by 'secondary compounds'.

I watched C. dromedarius foraging around the plants of A. hispidum, but not eating them. I also directly offered A. hispidum to C. dromedarius, which rejected the species.

I infer that the chemical defences of this daisy make it unpalatable to the dromedary.

(By the way, I also offered the foliage of what I take to be Lagenaria sphaerica (https://www.inaturalist.org/taxa/588490-Lagenaria-sphaerica) to C. dromedarius, which likewise rejected the offering. Our Samburu guides told me that this cucurbit is eaten by Loxodonta africana.

MOLE-RAT

On one occasion, I observed holes in the track, where it crossed a small seasonal watercourse, with earth being spurted out of them, presumably by Heterocephalus glaber (https://en.wikipedia.org/wiki/Naked_mole-rat).

BIRDS

Streptopelia capicola (https://www.inaturalist.org/taxa/2959-Streptopelia-capicola) and Streptopelia decipiens (https://www.inaturalist.org/taxa/2951-Streptopelia-decipiens) were both common at the time, together with Oena capensis (https://www.inaturalist.org/taxa/3652-Oena-capensis) and possibly Turtur chalcospilos (https://www.inaturalist.org/taxa/3327-Turtur-chalcospilos).

REPTILES AND AMPHIBIANS

Only two snakes, both smallish and unjdentified, on the whole excursion

Green chameleon, probably Chamaeleo gracilis (https://www.inaturalist.org/taxa/32845-Chamaeleo-gracilis), on sandy track as we walked

Lacertids were the commonest reptiles encountered. Several times during each day's walk, I saw lacertids, possibly Heliobolus spekii (https://www.inaturalist.org/taxa/35972-Heliobolus-spekii), but possibly also Pseuderemias smithii (https://www.inaturalist.org/taxa/35505-Pseuderemias-smithii).

One individual of a 'road-running' agamid, reminiscent of Australian forms, possibly Agama persimilis (https://www.inaturalist.org/taxa/31128-Agama-persimilis)

A few individuals of rock agamids, probably Agama lionotus (https://www.inaturalist.org/taxa/31155-Agama-lionotus)

One individual of a squattish ground/litter agamid reminiscent of Australian ?hispidus, possibly Agama rueppellii (https://www.inaturalist.org/taxa/31122-Agama-rueppelli)

One individual of a gecko, in dead wood on bank of Milgis River, as we collected firewood

Sundry frogs, including an individual with only one hind leg (the other bitten off at the base)

SHEEP NEONATE

While in Maralal, I encountered a newborn individual of Ovis aries, belonging to the black-headed dorper breed (https://www.google.com.au/search?q=+dorper+sheep+in+kenya&sxsrf=APwXEdf83NwXJ8eyVXRPdPvHtdNzXzs_Qg%3A1683764030546&ei=PjNcZMbzINPXseMP0aOWsAU&ved=0ahUKEwjGirTn_ev-AhXTa2wGHdGRBVYQ4dUDCA8&uact=5&oq=+dorper+sheep+in+kenya&gs_lcp=Cgxnd3Mtd2l6LXNlcnAQAzIFCAAQgAQyBggAEBYQHjIGCAAQFhAeMgYIABAWEB4yBggAEBYQHjIGCAAQFhAeMgYIABAWEB4yBggAEBYQHjIGCAAQFhAeMgYIABAWEB46CggAEEcQ1gQQsAM6BggAEAcQHjoKCC4QsQMQigUQQzoRCC4QrwEQxwEQ1AIQigUQkQI6BwgAEIoFEEM6GAguELEDEIoFEEMQlwUQ3AQQ3gQQ3wQYAToKCAAQigUQyQMQQzoICAAQgAQQkgM6CAgAEIoFEJECOgoILhCKBRCxAxBDOhgILhCKBRCxAxBDEJcFENwEEN4EEN8EGAE6CwgAEIoFEJIDEJECSgQIQRgAUIELWM5FYP1OaAFwAXgAgAGAA4gBsCySAQgwLjEuMjEuMpgBAKABAcgBCMABAdoBBggBEAEYFA&sclient=gws-wiz-serp#fpstate=ive&vld=cid:6b4ca5d5,vid:N62lJKXUYXU and https://www.google.com.au/search?q=+dorper+sheep+in+kenya&sxsrf=APwXEdf83NwXJ8eyVXRPdPvHtdNzXzs_Qg%3A1683764030546&ei=PjNcZMbzINPXseMP0aOWsAU&ved=0ahUKEwjGirTn_ev-AhXTa2wGHdGRBVYQ4dUDCA8&uact=5&oq=+dorper+sheep+in+kenya&gs_lcp=Cgxnd3Mtd2l6LXNlcnAQAzIFCAAQgAQyBggAEBYQHjIGCAAQFhAeMgYIABAWEB4yBggAEBYQHjIGCAAQFhAeMgYIABAWEB4yBggAEBYQHjIGCAAQFhAeMgYIABAWEB46CggAEEcQ1gQQsAM6BggAEAcQHjoKCC4QsQMQigUQQzoRCC4QrwEQxwEQ1AIQigUQkQI6BwgAEIoFEEM6GAguELEDEIoFEEMQlwUQ3AQQ3gQQ3wQYAToKCAAQigUQyQMQQzoICAAQgAQQkgM6CAgAEIoFEJECOgoILhCKBRCxAxBDOhgILhCKBRCxAxBDEJcFENwEEN4EEN8EGAE6CwgAEIoFEJIDEJECSgQIQRgAUIELWM5FYP1OaAFwAXgAgAGAA4gBsCySAQgwLjEuMjEuMpgBAKABAcgBCMABAdoBBggBEAEYFA&sclient=gws-wiz-serp#fpstate=ive&vld=cid:584cc3db,vid:5cjx2DxmIGU).

I watched as it stood, active, within one hour of birth.

This is precocial by the standards of antelopes. It is also much more precocial than the neonate of Capra hircus, which is not necessarily smaller-bodied or shorter-legged, but is behaviourally not as active just after birth.

The newborn of C. hircus takes a day to achieve the coordination and independence achieved by O. aries in a few hours.

Ovis is among the few 'followers' among the ruminants, whereas Capra seem to be typical 'hiders'.

Posted on April 29, 2023 11:16 PM by milewski