Display of the tail in the greater kudu 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 Smithers (2005) 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 becomes 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 (e.g. compare S. strepsiceros with 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),
• is relatively narrow (e.g. compare S. strepsiceros, https://www.inaturalist.org/observations/66833288, with Nyala angasii, https://stock.adobe.com/search?k=nyala&asset_id=12902258), and
• has a relatively small tassel (e.g. compare S. strepsiceros, https://www.inaturalist.org/observations/63230031 and https://www.inaturalist.org/observations/126211004, with Taurotragus oryx, https://www.flickr.com/photos/rainbirder/8686401833).

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 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.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/kudu-bull-tragelaphus-strepsiceros-running-typical-393295483

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

https://www.gettyimages.com.au/detail/news-photo/female-greater-kudu-tragelaphus-strepsiceros-running-mala-news-photo/1371856599?phrase=kudu%20running&adppopup=true

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.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:8e9bad5f,vid:lK0zUZL8M0k

https://www.inaturalist.org/observations/65208337

https://www.alamy.com/stock-photo-a-side-view-of-a-male-kudu-running-21707642.html?imageid=D280E8A5-5AD2-4ED2-858A-499D065C7649&p=34420&pn=1&searchId=ec5b8b55ff6a6e3842fded3bf74e12ac&searchtype=0

https://www.alamy.com/stock-photo-side-view-of-a-young-kudu-running-in-dry-veld-21707607.html?imageid=689BBAF7-AE1C-49C5-A7E1-99E94478568E&p=34420&pn=1&searchId=ec5b8b55ff6a6e3842fded3bf74e12ac&searchtype=0

https://www.alamy.com/greater-kudu-tragelaphus-strepsiceros-female-running-st-lucia-wetlands-national-park-south-africa-image357425085.html?imageid=D1B0ACBD-D675-4F66-9C99-E8C52524F084&p=477095&pn=1&searchId=ec5b8b55ff6a6e3842fded3bf74e12ac&searchtype=0

https://www.alamy.com/stock-photo-a-side-view-of-a-male-kudu-running-21707638.html?imageid=F7C10AC4-B058-4A12-BF12-BEEB39E8F2D4&p=34420&pn=1&searchId=ec5b8b55ff6a6e3842fded3bf74e12ac&searchtype=0

https://www.alamy.com/stock-photo-greater-kudu-83197109.html?imageid=2E3AD135-4057-4DA3-8233-CE8C7501D9A8&p=257633&pn=1&searchId=ec5b8b55ff6a6e3842fded3bf74e12ac&searchtype=0

https://www.alamy.com/greater-kudu-image247765564.html?imageid=B1BF1323-7DC4-4815-A4E5-13A44C756DA8&p=257778&pn=1&searchId=ec5b8b55ff6a6e3842fded3bf74e12ac&searchtype=0

https://www.shutterstock.com/image-photo/greater-kudu-african-antelope-running-kruger-1536182384

https://www.gettyimages.com.au/detail/photo/kudu-royalty-free-image/1013824270?phrase=kudu%20running&adppopup=true

https://www.gettyimages.com.au/detail/photo/kudu-royalty-free-image/1013824272?phrase=kudu%20running&adppopup=true

https://www.gettyimages.com.au/detail/photo/kudu-galloping-in-hwange-zimbabwe-royalty-free-image/984093646?phrase=kudu%20running&adppopup=true

https://www.gettyimages.com.au/detail/photo/the-aerial-view-scenery-of-male-greater-kudu-royalty-free-image/1264884579?phrase=kudu%20running&adppopup=true

https://www.gettyimages.com.au/detail/photo/the-aerial-view-of-female-greater-kudu-running-on-royalty-free-image/1264882002?phrase=kudu%20running&adppopup=true

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/

https://www.alamy.com/greater-kudu-tragelaphus-strepsiceros-female-walking-on-the-edge-of-a-dirt-road-etosha-national-park-namibia-africa-image476724351.html?imageid=699BD1CD-4CEC-4A7B-899F-DC0E7B14DE8B&p=642197&pn=1&searchId=ec5b8b55ff6a6e3842fded3bf74e12ac&searchtype=0

https://www.alamy.com/stock-photo-greater-kudu-83199326.html?imageid=0B110543-D4BC-4D5B-85DD-004B74818675&p=257633&pn=1&searchId=ec5b8b55ff6a6e3842fded3bf74e12ac&searchtype=0

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.

Posted on Νοέμβριος 10, 2022 0840 ΠΜ by milewski