The three alcelaphin bovids of the Serengeti: a comparison of adaptive colouration, part 3

@tonyrebelo @jeremygilmore @matthewinabinett @paradoxornithidae @jwidness @davidbygott @akilee @zarek @hoppy1951 @deanthompson

...continued from https://www.inaturalist.org/journal/milewski/77617-the-three-alcelaphin-bovids-of-the-serengeti-a-comparison-of-adaptive-colouration-part-2#

In my portrayal of the adaptive colouration of the alcelaphins of the Serengeti, I have pointed out the following:

all three species, in the order C. mearnsi > D. jimela > A. cokii, tend to be dark enough to stand out from the background - as opposed to blending in by means of cryptic colouration (https://en.wikipedia.org/wiki/Crypsis#).

My claim, that this darkness is enough to confer overall conspicuousness, may seem subjective.

Can we test this in some relatively objective way?

One approach is to study photos in which carnivores - which are accepted as having inconspicuous colouration - share the same illumination as their potential prey. Are the alcelaphins really more conspicuous than their predators?

Fortunately, the Web is fairly rich in such photos.

When viewing these images, please ignore the hues (https://www.yourdictionary.com/hueand https://www.color-wheel-artist.com/hue/), which may not be visible to ungulates and carnivores. Also, ignore the spotting in felids.

Instead, please assess only the overall tones, i.e. the 'shades of grey' involved (https://www.thoughtco.com/tone-definition-in-art-182471).

We would expect the carnivores to have the same tone as the background. And, according to my interpretation, we would expect the alcelaphins to be darker than the background, particularly at the ventral silhouette of the torso, which is not countershaded (https://en.wikipedia.org/wiki/Countershading).

CONNOCHAETES MEARNSI

In C. mearnsi, most of the figure, except for the rump and back, can look dark - the 'white' beard notwithstanding.

The following show that the overall tone of Acinonyx jubatus does indeed approximately match the background (https://www.gettyimages.ie/detail/photo/five-cheetahs-eating-freshly-killed-wildebeest-royalty-free-image/1156089749?adppopup=true and https://www.gettyimages.ie/detail/photo/cheetah-and-wildebeests-royalty-free-image/522055226?adppopup=true and https://www.gettyimages.ie/detail/photo/hunting-cheetah-walking-past-a-herd-of-alerted-royalty-free-image/521346806?adppopup=true and https://www.gettyimages.ie/detail/photo/five-cheetahs-eating-freshly-killed-wildebeest-royalty-free-image/1156082561?adppopup=true and https://www.gettyimages.ie/detail/photo/cheetah-checking-the-menu-royalty-free-image/577276343?adppopup=true and https://www.gettyimages.ie/detail/photo/cheetah-chasing-a-wildebeests-royalty-free-image/979884918?adppopup=true and https://www.masterfile.com/image/en/700-02659760/cheetah-in-field-with-wildebeest and https://www.masterfile.com/image/en/400-04359181/a-cheetah-acinonyx-jubatus-stalking-wildebeest-connochaetes-on).

By contrast, C. mearnsi stands out clearly from the same background in all these photos.

When the illumination is such that the figures are backlit, the shaded profile of A. jubatus looks somewhat darker than the background. However, C. mearnsi remains far darker - even if far away - than the carnivore (https://www.gettyimages.ie/detail/photo/cheetah-looking-for-hunting-family-photo-royalty-free-image/1356665838?adppopup=true and https://www.gettyimages.ie/detail/photo/hunting-cheetahs-at-wild-royalty-free-image/1283499651?adppopup=true and https://www.gettyimages.ie/detail/photo/cheetah-hunting-at-wild-royalty-free-image/1205819956?adppopup=true).

In the following (https://www.shutterstock.com/image-photo/wildebeest-chasing-cheetahs-away-when-they-1501749692), we see C. mearnsi together with A. jubatus, under identical illumination and at the same distance. (Although the carnivore is spotted, the aspect relevant here is its overall tone, relative to the background of grass.)

This, again, bears out the darkness of C. mearnsi.

A similar rationale applies to Panthera leo, as follows.

The following are complicated by the carnivore being far closer to the observer than is C. mearnsi (https://www.agefotostock.com/age/en/details-photo/lioness-hunting-wildebeest-in-the-masai-mara/M12-1240338 and https://www.gettyimages.ie/detail/photo/wildebeest-vary-of-the-lioness-who-may-hunt-in-royalty-free-image/1255573298?adppopup=true and https://www.gettyimages.ie/detail/photo/lioness-by-wildebeest-herd-royalty-free-image/200215662-001?adppopup=true and https://www.alamy.com/lioness-panthera-leo-and-antelopes-ngorongoro-conservation-area-tanzania-africa-image359929086.html?imageid=24BA2952-819B-469D-AC4E-044D73205FEA&p=1132882&pn=1&searchId=88d097a7526f5b145ff0d57d236c6e7b&searchtype=0 and https://www.alamy.com/stock-photo-masai-lion-panthera-leo-nubica-adult-female-sitting-in-grass-with-52966297.html?imageid=30242AF5-DD72-4349-B792-323BE93C5E41&p=11592&pn=3&searchId=2955e9e926053fed62c3a57c031745e6&searchtype=0 and https://www.gettyimages.com.au/detail/photo/lion-male-lion-walking-past-a-herd-of-wildebeest-royalty-free-image/1372532300?phrase=hartebeests&adppopup=true and https://www.alamy.com/stock-photo-lion-chasing-a-prey-ngorongoro-crater-tanzania-16743209.html?imageid=0A87FE46-015F-4575-AD18-8066EB8BD78A&p=58344&pn=1&searchId=c29bbb8b2d5e95260957618c6ccc9c51&searchtype=0 and https://www.agefotostock.com/age/en/details-photo/lionesses-hunts-wildebeest-in-the-masai-mara/M12-1276084/1).

However, once again the difference in tone and overall conspicuousness is obvious, between C. mearnsi and P. leo.

In the following, the complication of differing distances is eliminated, confirming the conspicuous darkness of C. mearnsi (https://www.gettyimages.ie/detail/photo/wildebeest-charging-at-hunting-lioness-masai-mara-royalty-free-image/952005364?adppopup=true and https://www.gettyimages.ie/detail/photo/lioness-chasing-wildebeest-royalty-free-image/200562141-001?adppopup=true and https://www.alamy.com/stock-photo-a-hunting-lioness-at-sunset-is-jumping-behind-her-preyserengetitanzania-16061512.html?imageid=88527EC6-A37C-44FE-9616-2BE49514F840&p=50837&pn=1&searchId=c29bbb8b2d5e95260957618c6ccc9c51&searchtype=0 and https://www.alamy.com/stock-photo-a-hunting-lioness-at-sunset-is-running-behind-her-preyserengetitanzania-16064294.html?imageid=35B8278A-59DE-4937-B213-A7B510669DCB&p=50837&pn=1&searchId=c29bbb8b2d5e95260957618c6ccc9c51&searchtype=0).

When the carnivore is darkened by shading, the difference between it and C. mearnsi is reduced (https://www.gettyimages.ie/detail/photo/lioness-hunting-eastern-white-bearded-wildebeest-royalty-free-image/103458218?adppopup=truehttps://www.gettyimages.ie/detail/photo/lioness-hunting-wildebeest-masai-mara-game-reserve-royalty-free-image/952005360?adppopup=true).

DAMALISCUS JIMELA

The darkness of the figure is more subtle in D. jimela than in C. mearnsi. It is concentrated on the face, ventral torso, and the legs just above the carpals and the hocks.

It is unusual for photos to show darkness over most of the figure (https://www.dreamstime.com/ugandan-topi-antelope-queen-elizabeth-national-park-ishasha-sector-uganda-np-image164668026 and https://www.inaturalist.org/observations/105829394). The upper half of the torso usually retains medium tone.

The following sets of photos follow the same order as explained above, except that I have mixed A. jubatus with P. leo.

Carnivore closer to observer than D. jimela:

https://www.alamy.com/female-cheetah-walking-past-topi-antelope-staring-at-her-as-she-goes-image154324074.html and https://www.bing.com/images/search?view=detailV2&ccid=C%2BQUv9TC&id=EFEB8BBEEDD02B7AFA3DCAAB877EE11C8D87F4BC&thid=OIP.C-QUv9TCI31ND8mU78ncbQHaEq&mediaurl=https%3A%2F%2Fcheetah-watch.com%2Fwp-content%2Fuploads%2F2017%2F10%2Fcheetah-topi-1.jpg&exph=378&expw=600&q=masterfile+cheetah+topi&simid=607988153515511434&form=IRPRST&ck=1E206C897F50FB691D13B8E83CE8D633&selectedindex=7&ajaxhist=0&ajaxserp=0&vt=0&sim=11 and https://es.123rf.com/photo_9171909_an-adult-cheetah-ushered-away-by-a-small-herd-of-topi-in-kenya-s-masai-mara-national-park.html and https://www.alamy.com/stock-photo-lion-panthera-leo-adult-male-hunting-topi-damaliscus-lunatus-herd-47781745.html?imageid=06F69E99-F40A-4A81-A883-0DD7A0810265&p=11592&pn=2&searchId=ab8d461b779d7157f5d6e83219cfd398&searchtype=0 and https://www.alamy.com/africa-kenya-maasai-mara-national-reserve-young-lion-walking-away-from-topi-antelopes-credit-as-bill-young-jaynes-gallery-danitadelimont-com-image441444224.html?imageid=897EC99B-F9A7-4672-B497-167F87E6292A&p=16459&pn=1&searchId=88d097a7526f5b145ff0d57d236c6e7b&searchtype=
https://www.dreamstime.com/stock-image-twelve-against-three-image18956221
https://www.dreamstime.com/stock-photo-hunter-becomes-hunted-image18956290
https://www.dreamstime.com/royalty-free-stock-photography-scat-cat-image18956217

Carnivore at same distance as D. jimela, or farther:

https://twitter.com/dhritimanimages/status/1201353418779975681 and https://www.alamy.com/stock-photo-kenya-masai-mara-a-female-cheetah-hunts-a-topi-in-the-short-grass-30746266.html and https://www.wild4photographicsafaris.com/blog/view/the-big-cats-of-the-masai-mara-february-2019/trip-reports and https://1x.com/photo/1504160/latest:all and https://www.dreamstime.com/cheetah-chasing-adult-topi-full-speed-masai-mara-kenya-male-green-plains-image187309793 and https://solent.photoshelter.com/image/I00003EgASShK_5w and scroll to 14th and 15th photos in http://marameru.org/3331-2/ and https://www.bing.com/images/search?view=detailV2&ccid=zLrPMSal&id=28E4BBB9EEB20289DA75E51CA0BAF9F5CF14EAA0&thid=OIP.zLrPMSalHttUWkSQ1BLUmQHaHa&mediaurl=https%3A%2F%2Fi.pinimg.com%2Foriginals%2Faa%2Fdc%2Fa6%2Faadca60818f07211adaacab660f3b13b.jpg&exph=1080&expw=1080&q=masterfile+cheetah+topi&simid=608023251964493221&form=IRPRST&ck=D81E7A2EF7923E0A4D1F7F8D950C7FA9&selectedindex=0&ajaxhist=0&ajaxserp=0&vt=0&sim=11 and https://www.alamy.com/thrilling-and-action-packed-images-of-two-young-cheetahs-chasing-a-topi-have-been-captured-in-masai-mara-kenya-images-captured-show-two-male-cheet-image503817454.html and https://www.bing.com/images/search?view=detailV2&ccid=Vjz5HJnX&id=B4F2D8A9C8375DECDBB6365B8F56A126F9C5FE4E&thid=OIP.Vjz5HJnXnVoq-VL5x8curwHaE8&mediaurl=https%3a%2f%2fblog.africadreamsafaris.com%2fwp-content%2fuploads%2f2010%2f08%2fcheetah_topi_battle_0004_04.jpg&exph=360&expw=540&q=masterfile+cheetah+topi&simid=608001781435034413&FORM=IRPRST&ck=64E6B8A9D05F920814035C5FAC00C263&selectedIndex=12&ajaxhist=0&ajaxserp=0 and https://www.bing.com/images/search?view=detailV2&ccid=JwSXtKxx&id=4DF1A88508E6E65314E50D0FC675DB7D3E41AE37&thid=OIP.JwSXtKxxqmc3zLzpt2TxMwAAAA&mediaurl=https%3A%2F%2Fth.bing.com%2Fth%2Fid%2FR.270497b4ac71aa6737ccbce9b764f133%3Frik%3DN65BPn3bdcYPDQ%26riu%3Dhttp%253a%252f%252fn450v.alamy.com%252f450v%252fdak0c3%252fcheetah-acinonyx-jubatus-running-past-a-topi-damaliscus-jimela-lunatus-dak0c3.jpg%26ehk%3DJ1Zlas7jfJ1ywuFsPCofeA8WqgqIIiJT3We1z%252fu%252feWA%253d%26risl%3D%26pid%3DImgRaw%26r%3D0&exph=320&expw=450&q=masterfile+cheetah+topi&simid=607989149943093715&form=IRPRST&ck=922E58C774838C60EDACFB8D3C4DEF0A&selectedindex=78&ajaxhist=0&ajaxserp=0&vt=0&sim=11

In the following direct illumination, the figure of D. jimela shows no conspicuous darkness (https://www.alamy.com/lioness-panthera-leo-hunting-and-topis-masai-mara-game-reserve-kenya-image262964121.html?imageid=B70CF3CB-EF33-4491-AC22-EE3F69A0D555&p=269351&pn=1&searchId=88d097a7526f5b145ff0d57d236c6e7b&searchtype=0). Few photos show this effect in C. mearnsi.

Overall, the above show enough darkness in D. jimela, located on the face and ventrally, to make the whole figure somewhat conspicuous at the relevant distances.

ALCELAPHUS COKII

There are few relevant photos on the Web.

However, such evidence as there is suggests that A. cokii, too, tends to be somewhat darker, overall, than A. jubatus - the pale buttocks and haunches notwithstanding.

https://www.dreamstime.com/close-up-two-cheetah-watching-hartebeest-antelope-close-up-two-cheetah-watching-hartebeest-antelope-serengeti-national-image176751187 and https://www.bing.com/images/search?view=detailV2&ccid=TN0wGtcW&id=F80062D770AFE80B037F2F156D5925DF19769918&thid=OIP.TN0wGtcW8ryh-hYvAu3HSgHaE8&mediaurl=https%3A%2F%2Fth.bing.com%2Fth%2Fid%2FR.4cdd301ad716f2bca1fa162f02edc74a%3Frik%3DGJl2Gd8lWW0VLw%26riu%3Dhttp%253a%252f%252fwww.shahrogersphotography.com%252fgallery%252fUpload%252fUpload4%252fMM08-2854.jpg%26ehk%3Dk%252fMWQ%252fWID%252bbFJejUDUwVuRgig12MYcUgwgnshWIpFeQ%253d%26risl%3D%26pid%3DImgRaw%26r%3D0&exph=427&expw=640&q=masterfile+cheetah+topi&simid=608005513759503637&form=IRPRST&ck=B71CC59F052E99ACFDE8650A426DA45A&selectedindex=152&ajaxhist=0&ajaxserp=0&vt=0&sim=11 and https://www.flickr.com/photos/wild_images/7091025929/ and https://www.gettyimages.com.au/detail/photo/cheetah-hunting-hartebeest-royalty-free-image/126279871?phrase=hartebeests&adppopup=true

The following photo nicely summarises the overall findings of this Post (https://www.alamy.com/stock-photo-lion-chasing-a-prey-ngorongoro-crater-tanzania-16741666.html?imageid=A63A1D62-49B1-4C78-9D81-1A9288554E78&p=58344&pn=1&searchId=c29bbb8b2d5e95260957618c6ccc9c51&searchtype=0).

For an index to my many Posts about the genus Damaliscus, please see https://www.inaturalist.org/journal/milewski/78238-an-index-to-my-posts-on-genus-damaliscus#.

Posted on 10 April, 2023 06:35 by milewski