Display of the tail in the greater kudu (Strepsiceros) is puzzlingly subtle and inconsistent
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Any naturalist familiar with the greater kudu (Strepsiceros strepsiceros, https://www.inaturalist.org/taxa/42339-Tragelaphus-strepsiceros) knows that this bovid ruminant sometimes displays the white of its tail while fleeing (https://www.inaturalist.org/observations/57527503 and https://www.pixoto.com/images-photography/animals/other-mammals/running-kudu-106003874 and https://www.google.com.au/search?q=Kudu+runnj+g&sxsrf=ALiCzsblhLkPP5500O9vjkN1cBJu2HnQxw%3A1668069411255&source=hp&ei=I7hsY6eNB9yV4-EPx4aHsAE&iflsig=AJiK0e8AAAAAY2zGM38ZXqwHjsyinLP2UlJasM_qpKSY&ved=0ahUKEwjnqtflmqP7AhXcyjgGHUfDARYQ4dUDCAo&uact=5&oq=Kudu+runnj+g&gs_lcp=Cgdnd3Mtd2l6EAMyBwgAEIAEEA0yBggAEB4QDTIICAAQCBAeEA0yCAgAEAgQHhANMggIABAIEB4QDTIFCAAQhgMyBQgAEIYDMgUIABCGAzIFCAAQhgM6BwgjEOoCECc6BAgjECc6CAguENQCEJECOgsILhDHARCvARCRAjoRCC4QgAQQsQMQgwEQxwEQ0QM6BQguEIAEOggILhCxAxCDAToOCC4QgAQQsQMQxwEQ0QM6BQguEJECOgsILhCvARDHARCABDoICC4QgAQQsQM6CwgAEIAEELEDEIMBOgsILhCDARCxAxCRAjoICAAQgAQQsQM6CwguEIAEEMcBEK8BOgUIABCABDoOCC4QgAQQsQMQxwEQrwE6CwguENQCELEDEIAEOggILhDUAhCABDoLCC4QgAQQxwEQ0QM6BggAEBYQHjoICAAQFhAeEA86BQghEKABUPQKWOUpYJ4uaAFwAHgAgAG_AogBzReSAQYyLTExLjGYAQCgAQGwAQo&sclient=gws-wiz#fpstate=ive&vld=cid:fd6601a1,vid:sthInuu-2DA).
Skinner and Chimimba (2005, https://www.cambridge.org/core/books/mammals-of-the-southern-african-subregion/5C2E1D1A9BD464C8A0F3D5A550595AFA) state:
"They...run, with the tail curled upward to show a flash of white hair. This visual contact signal assists calves and subordinates in following group leaders during flight, especially at night".
However, it is only when one focuses on this phenomenon that its subtlety and inconsistency become apparent.
First let us examine the tail when it is inert.
The tail of the greater kudu is proportionately smaller than in most other Bovinae (https://en.wikipedia.org/wiki/Bovinae). This is because it
- is relatively short and narrow, and
- has a relatively small tassel.
The following clearly shows the length of the tail in an adult but not fully mature male individual (https://www.inaturalist.org/observations/41232462).
Please compare this with e.g. Boselaphus tragocamelus:
https://upload.wikimedia.org/wikipedia/commons/4/4f/Nilgai_in_the_water%2C_with_his_tail_up.jpg and https://www.agefotostock.com/age/en/details-photo/nilgai-boselaphus-tragocamelus-these-large-asian-antelope-are-endemic-to-the-indian-subcontinent-photographed-in-national-chambal-sanctuary-india/SPL-c0417385),
The following shows the breadth of the tail in S. strepsiceros (https://www.inaturalist.org/observations/66833288).
Please compare this with Nyala angasii:
https://stock.adobe.com/search?k=nyala&asset_id=12902258.
The following shows the size of the tail tassel in S. strepsiceros (https://www.inaturalist.org/observations/63230031 and https://www.inaturalist.org/observations/126211004).
Please compare this with Taurotragus oryx:
https://www.flickr.com/photos/rainbirder/8686401833.
In S. strepsiceros, the ventral/inner pelage of the tail, apart from the tassel, is consistently white.
However, the tassel is not consistently dark (https://www.inaturalist.org/observations/90813594 and https://www.inaturalist.org/observations/34948213). In some individuals, the tassel may be paler than the shaft of the tail (https://www.inaturalist.org/observations/52752110).
The tail of the greater kudu changes in proportional size with age since birth, as follows:
- it is broader in juveniles (https://www.inaturalist.org/observations/73403847 and https://www.inaturalist.org/observations/98392798 and https://www.inaturalist.org/observations/37401716) than in adults (https://www.inaturalist.org/observations/70313880), and
- it is proportionately smallest in mature males (https://www.inaturalist.org/observations/104639376).
In some individuals, the tail, when inert, is so nondescript as to be hardly noticeable (https://www.inaturalist.org/observations/86262493 and https://www.inaturalist.org/observations/119025737 and https://stock.adobe.com/search?k=%22kudu+bull%22&asset_id=385914266 and https://stock.adobe.com/search?k=%22kudu+bull%22&asset_id=385913821 and https://www.inaturalist.org/observations/139994742).
The following are additional views of the INERT TAIL.
Adult males:
https://www.inaturalist.org/observations/137158564
https://www.inaturalist.org/observations/103481419
https://www.inaturalist.org/observations/72047217
https://www.inaturalist.org/observations/122628287
https://www.inaturalist.org/observations/130030877
https://www.inaturalist.org/observations/135677651
https://www.inaturalist.org/observations/125970730
https://www.inaturalist.org/observations/136722305
https://www.inaturalist.org/observations/57223607
Adolescent males:
https://www.inaturalist.org/observations/125336251
https://www.inaturalist.org/observations/108449504
Adult females:
https://www.inaturalist.org/observations/30877620
https://www.inaturalist.org/observations/29982612
https://www.inaturalist.org/observations/137962439
https://www.inaturalist.org/observations/60425467
https://www.inaturalist.org/observations/107476082
https://www.inaturalist.org/observations/122021870
https://www.inaturalist.org/observations/107383190
https://www.inaturalist.org/observations/130151756
https://www.inaturalist.org/observations/30461726
Juveniles:
https://www.inaturalist.org/observations/67564032
https://www.inaturalist.org/observations/132925603
https://www.inaturalist.org/observations/72646966
ASPECTS OF SUBTLETY
In the greater kudu, caudal flagging during running from potential predators is relatively subtle, because
- the tail is relatively small (e.g. compare https://www.leesonphoto.com/image/I0000XRk.YNL.lR8 and https://adventures.everybodyshops.com/white-tails-whitetails-predictors-future/),
- the white pelage on the tail is hardly flared (e.g. compare https://www.flickr.com/photos/idahoeyes/13909043581 and https://www.agefotostock.com/age/en/details-photo/white-tailed-deer-buck-with-tail-up-to-signal-to-other-deer-that-an-intruder-is-in-the-woods-odocoileus-virginianus/MEV-10763040), and
- no dark feature is prominently displayed when the tail is curled up.
In this species and tragelaphins generally, there is no dark/pale contrast between the bare anal skin and the white pelage of the tail (https://www.inaturalist.org/observations/135528840).
This is because the anal/perineal skin is merely flesh-coloured (https://www.inaturalist.org/observations/9867281 and https://www.inaturalist.org/observations/17883332 and https://www.inaturalist.org/observations/28783830 and https://www.inaturalist.org/observations/27848859 and https://www.inaturalist.org/observations/129150382).
By contrast, the anal skin is dark in various other bovids (e.g. https://www.alamy.com/close-up-of-a-fringe-eared-oryx-oryx-beisa-callotis-with-long-black-tasseled-tail-muscular-fawn-coloured-body-black-bands-white-muzzle-and-long-c-image261842455.html?imageid=83858366-757A-48AE-84DA-CBB79B414612&p=856738&pn=1&searchId=2acdd3c77239b8025e32abf767a9eb0f&searchtype=0 and https://www.shutterstock.com/image-photo/gemsbok-pair-female-has-bend-horn-1463639066 and https://www.shutterstock.com/image-photo/oryx-gemsbok-walking-tail-swishing-namibia-1262532445 and https://www.shutterstock.com/image-photo/few-stripped-gemsboks-walking-feeding-together-2383345649 and https://www.gettyimages.ae/detail/photo/side-view-of-deer-standing-on-field-narok-masai-royalty-free-image/1323908665?adppopup=true and https://www.flickr.com/photos/93856865@N07/8555121252/).
ASPECTS OF INCONSISTENCY
In the greater kudu, caudal flagging during running from potential predators is relatively inconsistent, because
the breadth of white pelage exposed varies between juveniles (https://www.shutterstock.com/image-photo/greater-kudu-antelope-wildlife-africa-escaping-143702860
and https://www.alamy.com/africa-zambia-south-luangwa-national-park-greater-kudu-wild-tragelaphus-strepsiceros-image334347953.html?imageid=5E9E62A3-CCF3-4750-B27D-E6B0351D4C1A&p=88978&pn=1&searchId=921c119154c69cc93973ece28d6aca19&searchtype=0) and adults,- the tassel is only sometimes noticeable as a dark feature,
- the tail is sometimes only half-curled,
- the tail is not activated during trotting, and
- the tail is not necessarily activated at all.
In the approximately 50 photos collated below, only a quarter show full caudal flagging during running, with the tail curled into a loop in which the tassel touches the base of the tail (https://www.shutterstock.com/image-photo/greater-kudu-african-antelope-running-kruger-1584305581 and https://www.gettyimages.com.au/detail/photo/running-kudu-royalty-free-image/1032996632?phrase=kudu%20running&adppopup=true).
The following show the tail fully ACTIVATED during running.
https://www.sciencephoto.com/media/954350/view/greater-kudu-jumping-over-a-stream
https://www.shutterstock.com/image-photo/mature-kudu-bull-running-waterhole-mud-1442546963
https://www.shutterstock.com/image-photo/greater-kudu-females-running-okavango-37721911
https://www.shutterstock.com/image-photo/male-greater-kudu-running-on-dune-1565439895
https://www.shutterstock.com/image-photo/greater-kudu-jumping-over-gravel-road-1526995457
https://www.shutterstock.com/image-photo/greater-kudus-on-run-predator-kalahari-1600122685
https://www.shutterstock.com/image-photo/running-kudus-kruger-national-park-1581550462
https://www.flickr.com/photos/8444492@N05/5010070678/
https://www.inaturalist.org/observations/54141662
https://www.inaturalist.org/observations/138032407
https://www.inaturalist.org/observations/137608528
The following show the tail NOT activated during running.
https://www.canstockphoto.com/greater-kudu-bull-18497847.html
https://es.123rf.com/photo_45240397_kudu-s-running.html
https://www.inaturalist.org/observations/65208337
https://www.shutterstock.com/image-photo/greater-kudu-african-antelope-running-kruger-1536182384
https://www.shutterstock.com/image-photo/greater-kudu-running-away-waterhole-etosha-107227049
https://www.shutterstock.com/image-photo/kudu-bull-runs-away-after-sensing-53182714
https://www.shutterstock.com/image-photo/kudu-running-on-grassland-africa-2028663815
https://www.shutterstock.com/image-photo/female-kudu-running-across-dirt-track-654022627
https://www.shutterstock.com/image-photo/kudo-running-away-chobe-national-park-163656551
https://www.shutterstock.com/image-photo/male-kudu-antelope-big-horns-running-1344156947
The following show the tail SEMI-ACTIVATED during running.
https://www.inaturalist.org/observations/10873077
https://www.shutterstock.com/image-photo/young-kudu-female-running-through-grassland-1280900029
https://www.shutterstock.com/image-photo/greater-kudu-kodoo-tragelaphus-strepsiceros-male-2101732756
https://www.dpchallenge.com/image.php?IMAGE_ID=675569
https://www.shutterstock.com/image-photo/namibia-onguma-game-reserve-kudu-running-649908403
https://www.shutterstock.com/image-photo/male-kudu-bull-running-away-danger-1591944553
https://www.shutterstock.com/image-photo/greater-kudu-kruger-national-park-south-1213822375
https://www.shutterstock.com/image-photo/young-male-kudu-antelope-running-clearing-1279959283
https://www.shutterstock.com/image-photo/huge-kudu-bull-starts-his-dash-11968057
https://www.shutterstock.com/image-photo/greater-kudu-bull-jumping-1316042189
https://www.shutterstock.com/image-photo/wild-african-greater-kudu-6-695857858
https://www.flickr.com/photos/spike2000/154248940
https://sperka.info/category/z-species/kudu/
DISCUSSION
The subtlety and inconsistency of the anatomy, colouration, and activation of the tail in S. strepsiceros may help to explain why most of the descriptions, in field guide-books, are inept or misleading.
For example:
- Stuart and Stuart (https://www.abebooks.com/Field-Guide-Larger-Mammals-Africa-Revised/31201292777/bd) state: "the tail is bushy, dark above and white below...When they run, the tail is usually raised vertically"; in fact, the tail is not bushy except (to some degree) in juveniles, the tail is never dark on its dorsal surface (except for the small, terminal tassel, in most individuals), and the tail is raised but hardly ever vertically (the only exception, out of hundreds of photos, is https://www.shutterstock.com/image-photo/two-greater-kudus-jumping-they-run-1169981746 );
- Dorst (https://www.amazon.com/Field-Larger-Mammals-Africa-Collins/dp/0002192942) states that the activation of the tail is one of "throwing the tail up", which is correct in only the vaguest sense;
- Astley Maberly (https://www.amazon.com/Mammals-South-Africa-Popular-Field/dp/0908387636) states: "when alarmed and cantering away, kudu curl their bushy tails over the rump, fanning out the white under-surface into a most conspicuous 'white flag' "; in fact, the tail is curled up but not over the rump, the tail is somewhat bushy in juveniles but not in adults, there is no significant fanning of the white pelage, and the caudal flag is not nearly as conspicuous as in e.g. the white-tailed deer (Odocoileus virginianus) or the grey rhebok (Pelea capreolus);
- Estes (https://www.goodreads.com/review/show/1468949051) states: "in flight, the tail is raised to show the white scut (as in reedbucks)"; this is misleading because reedbucks (Redunca) do not generally flag the tail when fleeing or running; and
- Kingdon (https://www.andrewisles.com/pages/books/10394/jonathan-kingdon/the-kingdon-field-guide-to-african-mammals) and Diller (https://www.biblio.com/book/field-guide-mammals-africa-including-madagascar/d/1295905381) do not mention the displaying of the tail at all.
Also please see https://www.inaturalist.org/journal/milewski/80254-does-the-greater-kudu-strepsiceros-possess-an-anterior-auricular-flag#
Comentarios
Shift
CROSS-WALK IN OREOTRAGUS
https://www.shutterstock.com/image-photo/klipspringer-545588413
@matthewinabinett
REMARKABLE VARIATION IN INCIDENCE OF BEARD/'VENTRAL MANE' IN MATURE MALE STREPSICEROS:
Greater kudu in eastern Tanzania:
https://www.inaturalist.org/observations/107057160
Greater kudu near Kruger National Park, South Africa:
https://www.inaturalist.org/observations/43002278
https://www.inaturalist.org/observations/70864473
https://www.inaturalist.org/observations/64063109
Shift
Antilocapra americana
https://www.flickr.com/photos/voide/4008886982
https://www.inaturalist.org/observations/49712613
Caudal flagging by adult female greater kudu while micturating. Mature male performing flehmen:
https://www.inaturalist.org/observations/41402999
https://www.inaturalist.org/observations/37450470
https://www.inaturalist.org/observations/34610159
https://www.inaturalist.org/observations/9965129
RUSA UNICOLOR, which is an approximate ecological counterpart for the greater kudu in Asia:
https://www.youtube.com/watch?v=CsXJOGkUYJo
https://www.alamy.com/stock-photo-the-image-of-sambar-deer-rusa-unicolor-giving-alarm-call-in-tadoba-105852772.html
https://www.dreamstime.com/full-shot-alert-male-sambar-deer-rusa-unicolor-tail-up-taking-smell-predator-foot-stamping-ranthambore-full-video205655224
https://www.superstock.com/asset/sambar-deer-cervus-unicolor-giving-alarm-call-tadoba-andhari-national/4138-20003132
https://www.google.com.au/search?q=Sambar+deer+in+alarm&source=lmns&tbm=vid&bih=535&biw=1000&hl=en&sa=X&ved=2ahUKEwjUneTwvKf7AhXaALcAHSxADPsQ_AUoAnoECAEQAg#fpstate=ive&vld=cid:5583097d,vid:zIxsGvb0a60
https://www.google.com.au/search?q=Sambar+deer+in+alarm&source=lmns&tbm=vid&bih=535&biw=1000&hl=en&sa=X&ved=2ahUKEwjUneTwvKf7AhXaALcAHSxADPsQ_AUoAnoECAEQAg#fpstate=ive&vld=cid:6cffff92,vid:RpwozInmXG0
https://www.dreamstime.com/deer-white-tailed-deer-animal-photo-deer-white-tailed-deer-animal-close-up-profile-view-deer-white-tailed-deer-animal-close-up-image165589990
https://m.youtube.com/watch?v=826HMLoiE_o
If I'm not mistakened, the Strepsiceros is represented by the above media footage, from a BBC series narrated by Sir David Attenborough. What can be surmised in relation to the movement of the kudus in the aforementioned footage?
@paradoxornithidae Many thanks for this most interesting clip.
Adult female Tragelaphus sylvaticus sylvaticus, showing breadth of tail:
https://www.inaturalist.org/observations/67977253
Please see https://www.inaturalist.org/posts/80254-does-the-greater-kudu-strepsiceros-possess-an-anterior-auricular-flag#activity_comment_c4314db2-7693-4402-b3d5-741755b3ea7a
Thank you. Dispels the myth that I always believed.
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