Unlike the blesbok, the bontebok (Damaliscus pygargus pygargus) lacks an auricular flag

@jwidness @michalsloviak @tonyrebelo @simontonge @jeremygilmore @oviscanadensis_connerties @tandala @colin25 @beartracker @grinnin @botswanabugs @gigilaidler @christiaan_viljoen

Dear Reader, what do you notice about the ears in the following photos?

Blesbok
https://www.inaturalist.org/observations/70348639

Bontebok
https://www.inaturalist.org/observations/115957749

The adaptive colouration of the two subspecies of Damaliscus pygargus is intriguing.

The bontebok (Damaliscus pygargus pygargus) and the blesbok (Damaliscus pygargus phillipsi) are, in most respects, more and less vivid versions of each other.

Therefore, it would have surprised nobody if a conspicuous feature of colouration in the blesbok were even more conspicuous in the bontebok.

Yet, in the case of the auricular flag, the opposite is the case.

In both subspecies, the posterior surface of the ear pinnae is greyish, apparently owing to the dark skin being sparsely covered with short, pale pelage (https://www.dreamstime.com/royalty-free-stock-images-african-bontebok-antelope-image6502609).

Because this pelage has a sheeny quality, the ear pinnae can appear conspicuously pale in certain illuminations.

And this sheeny pallor, although a small feature relative to the size of the whole animal, can serve as a social signal by virtue of the mobility of the ear pinnae.

The following footage of the blesbok is illustrative:

https://stock.adobe.com/search?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=1&filters%5Bcontent_type%3Atemplate%5D=1&filters%5Bcontent_type%3A3d%5D=1&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=damaliscus&order=relevance&safe_search=1&limit=100&search_page=16&search_type=pagination&get_facets=0&asset_id=554758522

https://stock.adobe.com/search/images?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=1&filters%5Bcontent_type%3Atemplate%5D=1&filters%5Bcontent_type%3A3d%5D=1&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=damaliscus&order=relevance&safe_search=1&limit=100&search_page=8&search_type=pagination&get_facets=0&asset_id=542644196

https://stock.adobe.com/search?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=1&filters%5Bcontent_type%3Atemplate%5D=1&filters%5Bcontent_type%3A3d%5D=1&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=damaliscus&order=relevance&safe_search=1&limit=100&search_page=16&search_type=pagination&get_facets=0&asset_id=555590119

What is particularly intriguing:

Contrary to expectations, it is the generally duller subspecies, namely the blesbok, that qualifies as possessing an auricular flag, whereas the more vivid subspecies, namely the bontebok, does not.

The failure of the bontebok to qualify for an auricular flag is owing to the following factors:

• the pelage on the posterior surface of the ear pinna seems to be somewhat less sheeny than in the blesbok, and
• the far greater conspicuousness of the sheeny dorsal 'saddle' in the bontebok than in the blesbok means that, in posterior/posteriolateral view, the ear pinnae are 'eclipsed' by the more noticeable feature (https://www.inaturalist.org/observations/22321093 and https://www.inaturalist.org/observations/71049460 and third photo in https://www.inaturalist.org/observations/144908730).

BLESBOK (see https://www.inaturalist.org/journal/milewski/75748-adaptive-colouration-in-the-blesbok-damaliscus-pygargus-phillipsi#)

The following show the auricular flag in the blesbok:

https://stock.adobe.com/search?k=damaliscus&asset_id=528793101

https://www.dreamstime.com/stock-photo-blesbuck-late-afternoon-field-blesbok-antelope-endemic-to-south-africa-has-distinctive-white-image77761759

https://www.gettyimages.pt/detail/foto/portrait-of-a-blesbok-eating-grass-imagem-royalty-free/71104635?adppopup=true

https://www.robertharding.com/preview/764-6027/blesbok-damaliscus-pygargus-phillipsi-male-chasing-mountain-zebra/

https://www.gettyimages.pt/detail/fotografia-de-not%C3%ADcias/blesbok-in-the-bioparc-valencia-november-07th-fotografia-de-not%C3%ADcias/1440188664?adppopup=true

Third photo in https://www.inaturalist.org/observations/141372682

Second photo in https://www.inaturalist.org/observations/41711968

https://www.inaturalist.org/observations/146961908

https://www.inaturalist.org/observations/107178201

Scroll to second photo in http://cameratrap.mywild.co.za/2012/02/more-herbivores-at-suikerbosrand.html

https://stock.adobe.com/search?k=damaliscus&asset_id=574779666

https://stock.adobe.com/search/images?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=1&filters%5Bcontent_type%3Atemplate%5D=1&filters%5Bcontent_type%3A3d%5D=1&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=damaliscus&order=relevance&safe_search=1&limit=100&search_page=3&search_type=pagination&get_facets=0&asset_id=441942924

https://stock.adobe.com/search?k=damaliscus&asset_id=32501730

https://stock.adobe.com/search/images?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=1&filters%5Bcontent_type%3Atemplate%5D=1&filters%5Bcontent_type%3A3d%5D=1&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=damaliscus&order=relevance&safe_search=1&limit=100&search_page=2&get_facets=0&search_type=pagination&asset_id=447452844

https://upload.wikimedia.org/wikipedia/commons/2/22/Damalicus_pygargus_phillipsi_Dvur_zoo_2.jpg

https://www.inaturalist.org/observations/32226381

https://www.stockfreeimages.com/388844/Blesbok.html

https://upload.wikimedia.org/wikipedia/commons/1/13/Barcelona-Zoo-Damalisco_de_frente_blanca_%28Damaliscus_dorcas_phillipsi%29_%28I%29.jpg

https://www.gettyimages.pt/detail/foto/blesboks-running-imagem-royalty-free/90498079?adppopup=true

https://stock.adobe.com/search/images?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=0&filters%5Bcontent_type%3Atemplate%5D=0&filters%5Bcontent_type%3A3d%5D=0&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=blesbok&order=relevance&price%5B%24%5D=1&safe_search=1&search_page=2&get_facets=0&search_type=pagination&asset_id=544432988

Third photo in https://www.inaturalist.org/observations/10869372

https://www.inaturalist.org/observations/10805336

https://www.gettyimages.pt/detail/foto/blesbok-antelopes-in-swaziland-imagem-royalty-free/92951908?adppopup=true

https://www.euro-t-guide.com/See_Photo/Denmark/JUT-M_Grenaa/Ree_Park_Ebeltoft-2008-14.jpg

https://depositphotos.com/635653818/stock-photo-blesbok-blesbuck-damaliscus-pygargus-phillipsi.html

https://www.inaturalist.org/observations/56204460

https://de.wikipedia.org/wiki/Buntbock#/media/Datei:Damaliscus_pygargus_-_R%C3%A9serve_africaine_de_Sigean_02.jpg

Scroll to seventh photo in https://www.dailymaverick.co.za/article/2022-12-07-mountain-zebra-national-park-back-from-the-brink/

https://www.inaturalist.org/observations/147672580

https://www.mindenpictures.com/stock-photo-blesbok-damaliscus-dorcas-phillipsi-adult-female-with-calf-malolotja-naturephotography-image80144737.html

https://www.inaturalist.org/observations/108296682

https://www.istockphoto.com/photo/african-blesbok-antelope-gm541305272-96817503

https://www.istockphoto.com/photo/two-beautiful-blesboks-gm1388891630-446375145?phrase=blesbok%20male

https://www.shutterstock.com/it/image-photo/blesbok-blesbuck-damaliscus-dorcas-phillipsi-497011039

https://stock.adobe.com/search/images?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=1&filters%5Bcontent_type%3Atemplate%5D=1&filters%5Bcontent_type%3A3d%5D=1&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=damaliscus&order=relevance&safe_search=1&limit=100&search_page=8&search_type=pagination&get_facets=0&asset_id=252055834

https://stock.adobe.com/search/images?k=blesbock&asset_id=32186683

BONTEBOK

The following show that, in the bontebok, there is a hint of the same pattern.

https://upload.wikimedia.org/wikipedia/commons/f/f8/Bontebok_PA020073.JPG

https://www.inaturalist.org/observations/84604329

https://www.gettyimages.pt/detail/foto/oryx-imagem-royalty-free/974402214?adppopup=true

https://www.shutterstock.com/it/image-photo/endangered-bontebok-antelope-damaliscus-pygargus-dorcas-572224153

Scroll to sixth photo in https://www.melozhori.co.za/fun-facts-about-bontebok/

Second photo inhttps://www.inaturalist.org/observations/63340921

https://stock.adobe.com/search?k=damaliscus&asset_id=437876858

https://www.inaturalist.org/observations/99715628

Third photo in https://www.inaturalist.org/observations/104349170

https://www.inaturalist.org/observations/71049460

https://stock.adobe.com/search/images?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=1&filters%5Bcontent_type%3Atemplate%5D=1&filters%5Bcontent_type%3A3d%5D=1&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=damaliscus&order=relevance&safe_search=1&limit=100&search_page=3&search_type=pagination&get_facets=0&asset_id=221437252

https://fototravel.net/licencias/damaliscus-dorcas-dorcas-sudafrica/

https://stock.adobe.com/search/images?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=1&filters%5Bcontent_type%3Atemplate%5D=1&filters%5Bcontent_type%3A3d%5D=1&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=damaliscus&order=relevance&safe_search=1&limit=100&search_page=7&search_type=pagination&get_facets=0&asset_id=271748452

https://www.inaturalist.org/observations/114683864

Scroll to third photo in https://www.goodthingsguy.com/environment/the-bontebok-brought-back-from-the-edge-of-extinction/

https://www.inaturalist.org/observations/128976508

https://www.inaturalist.org/observations/115214084

https://depositphotos.com/240206084/stock-photo-bontebok-antelope-southern-african-savanna.html

https://www.inaturalist.org/observations/136011434

https://www.inaturalist.org/observations/115175564

Scroll to second photo in https://www.monaconatureencyclopedia.com/damaliscus-dorcas/?lang=en

https://www.inaturalist.org/observations/97174996

https://www.inaturalist.org/observations/59053711

https://www.inaturalist.org/observations/75893694

https://www.inaturalist.org/observations/115550547

https://www.inaturalist.org/observations/39079379

https://www.inaturalist.org/observations/22321093

https://www.inaturalist.org/observations/27817980

https://www.inaturalist.org/observations/34601885

https://www.inaturalist.org/observations/31418950

https://www.inaturalist.org/observations/63459199

https://www.inaturalist.org/observations/24374180

https://www.inaturalist.org/observations/23198842

https://www.inaturalist.org/observations/10796733

https://www.inaturalist.org/observations/11166243

https://www.inaturalist.org/observations/45157961

https://www.inaturalist.org/observations/80650367

https://www.inaturalist.org/observations/61544194

https://www.inaturalist.org/observations/70047849

https://www.inaturalist.org/observations/69368070

https://www.inaturalist.org/observations/99626194

The following of the bontebok nearly qualify as showing an auricular flag:

https://stock.adobe.com/search/images?k=blesbock&asset_id=432947109.

https://www.inaturalist.org/observations/148322103

DISCUSSION

The comparison can be summarised by means of the following photo-pair.

Blesbok
https://www.inaturalist.org/observations/32226381

Bontebok
https://www.inaturalist.org/observations/30830045

Were it the case that the bontebok was the sole form of Damaliscus pygargus, probably nobody would have noticed the colouration of its ear pinnae, at all.

However, the noticeable 'flashing' of the ears in the blesbok has set up a search-image. According to the standard set by the blesbok, the bontebok falls short.

There are thousands of photos of the bontebok on the Web, but few come close to showing the clarity and consistency of the auricular flag seen in this view of the blesbok: https://stock.adobe.com/search/images?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=0&filters%5Bcontent_type%3Atemplate%5D=0&filters%5Bcontent_type%3A3d%5D=0&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=blesbock&order=relevance&price%5B%24%5D=1&safe_search=1&limit=100&search_page=2&get_facets=0&search_type=pagination&asset_id=142342741.

The following pair of photos of the blesbok shows the full difference produced by angle of illumination, via the sheeny quality of the pelage on the posterior surface of the ear pinna:

https://stock.adobe.com/search/images?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=1&filters%5Bcontent_type%3Atemplate%5D=1&filters%5Bcontent_type%3A3d%5D=1&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=damaliscus&order=relevance&safe_search=1&limit=100&search_page=8&search_type=pagination&get_facets=0&asset_id=362066099 versus https://stock.adobe.com/search/images?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=1&filters%5Bcontent_type%3Atemplate%5D=1&filters%5Bcontent_type%3A3d%5D=1&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=damaliscus&order=relevance&safe_search=1&limit=100&search_page=8&search_type=pagination&get_facets=0&asset_id=256689589

The following shows the difference, within a single specimen (https://stock.adobe.com/search?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=1&filters%5Bcontent_type%3Atemplate%5D=1&filters%5Bcontent_type%3A3d%5D=1&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=damaliscus&order=relevance&safe_search=1&search_page=9&get_facets=0&search_type=pagination&asset_id=10848983).

A possible explanation for the lack of an auricular flag in the bontebok is that the behaviours of the two subspecies differ.

The blesbok habitually head-nods (https://stock.adobe.com/search/images?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=0&filters%5Bcontent_type%3Atemplate%5D=0&filters%5Bcontent_type%3A3d%5D=0&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=blesbock&order=relevance&price%5B%24%5D=1&safe_search=1&limit=100&search_page=5&search_type=pagination&get_facets=0&asset_id=415281887 and https://stock.adobe.com/search/images?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=0&filters%5Bcontent_type%3Atemplate%5D=0&filters%5Bcontent_type%3A3d%5D=0&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=blesbock&order=relevance&price%5B%24%5D=1&safe_search=1&limit=100&search_page=5&search_type=pagination&get_facets=0&asset_id=415281850 and https://stock.adobe.com/search/images?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=0&filters%5Bcontent_type%3Atemplate%5D=0&filters%5Bcontent_type%3A3d%5D=0&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=blesbock&order=relevance&price%5B%24%5D=1&safe_search=1&limit=100&search_page=7&search_type=pagination&get_facets=0&asset_id=415281880).

It does this to an extent and with a frequency that I have not noticed in the bontebok.

Head-nodding, as well as standing in the midday sun with the head lowered and the ears drooping, would tend to display the auricular flag (https://depositphotos.com/154297952/stock-video-blesbok-antelopes-in-grassland.html and https://www.dreamstime.com/stock-photo-cattle-bontebok-antelopes-south-africa-safari-tala-game-reserve-image45175407 and https://stock.adobe.com/search/images?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=1&filters%5Bcontent_type%3Atemplate%5D=1&filters%5Bcontent_type%3A3d%5D=1&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=damaliscus&order=relevance&safe_search=1&limit=100&search_page=8&search_type=pagination&get_facets=0&asset_id=566483214).

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#.

Publicado el marzo 2, 2023 06:18 TARDE por milewski