A concise photo-comparison of adaptive colouration between the tsessebe and the blesbok

@michalsloviak @tonyrebelo @jeremygilmore @ludwig_muller @paradoxornithidae @tandala @oviscanadensis_connerties @simontonge @jwidness

Please see https://www.inaturalist.org/journal/milewski/77112-adaptive-colouration-in-the-tsessebe-damaliscus-lunatus-using-the-related-blesbok-for-reference# and https://www.inaturalist.org/journal/milewski/75748-adaptive-colouration-in-the-blesbok-damaliscus-pygargus-phillipsi-part-1-adults#

In this summary, I refer to adults only, of the tsessebe (Damaliscus lunatus lunatus, https://www.alamy.com/topi-tsessebi-korrigum-tsessebe-damaliscus-lunatus-in-savanna-south-africa-mokala-national-park-image255402674.html?imageid=7A297C06-C0DB-4C75-83AE-3037C9C12D4E&p=851122&pn=1&searchId=303cfda7336cba6c5732f1db91b12f81&searchtype=0) and the blesbok (Damaliscus pygargus phillipsi, https://www.shutterstock.com/it/image-photo/blesbok-blesbuck-damaliscus-dorcas-phillipsi-497011045).

FACIAL BLEEZE ABSENT IN TSESSEBE BUT PRESENT IN BLESBOK

In the tsessebe, the rostrum is blackish, whereas in the blesbok the rostrum is whitish. Although these tones are both extreme, the effect is far less conspicuous in the tsessebe than in the blesbok, partly because of a lack of dark/pale contrast on the face of the tsessebe.

Tsessebe
https://stock.adobe.com/search/images?k=tsessebe&asset_id=175846122
https://stock.adobe.com/search/images?k=tsessebe&asset_id=145113726
https://stock.adobe.com/search/images?k=tsessebe&asset_id=22528301

Blesbok
https://dewetswild.com/tag/blesbok/#jp-carousel-40689
https://dewetswild.com/2016/06/23/blesbok/
https://www.freeart.com/artwork/art-print/blesbok-antelope_fa13514984.html

PYGAL FLAG PRESENT IN BOTH TSESSEBE AND BLESBOK

In both the tsessebe and the blesbok, the pelage on the upper, inner buttocks is pale, and that of the buttocks and base of tail, more broadly, is sheeny. Dependent on illumination, this can gleam conspicuously when the figure moves, even at a distance.

Tsessebe
https://depositphotos.com/3781313/stock-photo-tsessebe-antelope.html
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=tsessebe&order=relevance&price%5B%24%5D=1&safe_search=1&limit=100&search_page=2&get_facets=0&search_type=pagination&asset_id=496136014

Blesbok
https://www.flickr.com/photos/gerdavs/30537405800
https://unsplash.com/photos/6QUPjrFJ_cU
https://www.gettyimages.com.au/detail/photo/blesbok-royalty-free-image/1351086134?phrase=blesbok&adppopup=true
https://stock.adobe.com/search/images?k=blesbok&asset_id=357665041

ULNAR FLAG ABSENT IN TSESSEBE BUT PRESENT IN BLESBOK

In both the tsessebe and the blesbok, the pelage on the upper foreleg tends to be dark, with a pale patch on its posterior surface. This potentially complements the pygal flag, in posteriolateral view.

However, only in the blesbok is this conspicuous enough to qualify as a flag.

Tsessebe
https://www.flickr.com/photos/42964440@N08/52226882444
Scroll in https://mattanu.com/wp-content/uploads/2017/11/Kriek-Wildlife-Group-Journal-Kriek-Wildlife-Group-Journal.pdf

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=blesbok&order=relevance&price%5B%24%5D=1&safe_search=1&limit=100&search_page=3&search_type=pagination&get_facets=0&asset_id=514194342
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=216887690

ABDOMINAL FLAG ABSENT IN TSESSEBE BUT PRESENT IN BLESBOK

In both the tsessebe and the blesbok, the pelage immediately anterior to the knee tends to be pale. However, in the tsessebe this is not conspicuous enough to qualify as a flag, whereas in the blesbok the pelage in question is whitish, and conspicuous in/at certain illuminations and perspectives.

Tsessebe
https://www.flickr.com/photos/berniedup/50213649897

Blesbok
https://dewetswild.com/2016/06/23/blesbok/#jp-carousel-10761

PEDAL FLAG ABSENT IN TSESSEBE BUT PRESENT IN BLESBOK

In both the tsessebe and the blesbok, the pelage on the lower legs tends to be pale relative to that on the upper legs. This is potentially conspicuous when the animal walks.

However, only in the blesbok is this conspicuousness realised, because the inner surface of the lower foreleg in particular is whitish.

Tsessebe
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=tsessebe&order=relevance&price%5B%24%5D=1&safe_search=1&limit=100&search_page=6&search_type=pagination&get_facets=0&asset_id=424426185

Blesbok
https://www.alamy.com/blesbok-damaliscus-pygargus-phillipsi-adult-walking-in-open-grassland-mountain-zebra-national-park-eastern-cape-south-africa-africa-image229684222.html

AURICULAR FLAG ABSENT IN TSESSEBE BUT PRESENT IN BLESBOK

In both the tsessebe and the blesbok, the posterior surface of the ear pinna has medium tone in terms of its pigmentation. However, in the blesbok the sparse, short pelage on this surface is so sheeny that the back-of-ear appears conspicuously pale according to illumination and perspective. This effect is never seen in the tsessebe.

Tsessebe
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=tsessebe&order=relevance&price%5B%24%5D=1&safe_search=1&limit=100&search_page=3&search_type=pagination&get_facets=0&asset_id=137949696
https://stock.adobe.com/search/images?k=tsessebe&asset_id=275109674
https://dewetswild.com/2016/08/19/tsessebe/#jp-carousel-22068

Blesbok
https://www.dreamstime.com/stock-photo-blesbuck-late-afternoon-field-blesbok-antelope-endemic-to-south-africa-has-distinctive-white-image77761759
https://dewetswild.com/tag/blesbok/#jp-carousel-10763

CAUDAL FLAG ABSENT IN BOTH TSESSEBE AND BLESBOK

The tails of the tsessebe and the blesbok are surprisingly different in structure, considering that they belong to the same genus. The tail of the tsessebe is less conspicuous than that of the blesbok, because the dark tail-tassel is thin. However, neither the tsessebe nor the blesbok possesses a caudal flag, at least in the context of anti-predator displays. This is mainly because the tails are not raised or wagged in alarm or while fleeing.

Tsessebe
https://stock.adobe.com/search/images?k=tsessebe&asset_id=7408032
https://stock.adobe.com/search/images?k=tsessebe&asset_id=153266289
https://stock.adobe.com/search/images?k=tsessebe&asset_id=433137353

Blesbok
https://www.shutterstock.com/it/image-photo/adult-male-blesbok-damaliscus-pygargus-phillipsibrown-365902583
https://www.natureinstock.com/search/preview/blesbok-damaliscus-dorcas-phillipsi-running-rietvlei-nature-reserve/0_10092533.html
https://dewetswild.com/tag/blesbok/#jp-carousel-10774

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 30 March, 2023 18:34 by milewski milewski

Comments

The only photo that shows a hint of auricular flag in the tsessebe is https://www.inaturalist.org/observations/90239182.

Posted by milewski about 1 year ago
Posted by milewski about 1 year ago

According to Estes (1991):

page 143: 'Damaliscus lunatus' (in the loose sense) 'social and reproductive organization appears to be more variable than that of any other antelope'.

page 143:'Damaliscus lunatus': 'calves may be either hiders or followers'.

page 144, referring to jimela: 'Topi herds often, possibly even routinely, make a move at the end of their afternoon feeding peaks, just after dark before settling down to ruminate...Young calves then usually leave the herd one by one and go off 100 m or so to bed down for the night.'

According to Estes (1993):

page 114 (referring to Damaliscus lunatus in the loose sense): 'Typical hider system in dispersed, resident pattern, but in aggregations calves that would normally hide for 3 weeks stay with the aggregation by day, go off to spend the night in hiding soon after dark. Calves past hiding stage associate in creches.'

Posted by milewski 12 months ago

According to Estes (1991), page 143:

Referring to jimela in the Serengeti ecosystem:

"In the bull's absence, the dominant cow may actually behave like a territorial male, approaching intruding cows and even bulls in the rocking canter and performing the high-stepping display."

"...topis in aggregations often rest standing in parallel ranks, with eyes apparently closed, but keep nodding to one another. This behavior is particularly frequent in male groups and seems to be a form of signaling, but the meaning has yet to be deciphered."

Posted by milewski 12 months ago

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