A concise photo-guide to the differences (some previously overlooked) between blesbok and bontebok

I have recently scrutinised all of the thousands of photos, on the Web, of Damaliscus pygargus (https://www.inaturalist.org/taxa/42275-Damaliscus-pygargus).

The following are my findings, w.r.t. the differences in appearance between the two subspecies.

In all cases, I show the blesbok (Damaliscus pygargus philipsi) first, and the bontebok (Damaliscus pygargus pygargus) second.

Please note that sexual dimorphism is greater in the blesbok than in the bontebok.

MALE BODY FORM STOUTER IN BLESBOK

Blesbok https://es.123rf.com/photo_27663869_a-blesbok-antelope-damaliscus-pygargus-standing-in-grassland-south-africa.html
Bontebok https://www.krugerpark.co.za/africa_bontebok.html

HORNS LONGER IN BLESBOK

Female:

Blesbok https://www.dreamstime.com/royalty-free-stock-photos-blesbok-antelope-image3045098
Blesbok https://www.agefotostock.com/age/en/details-photo/blessbock-damaliscus-pygargus-phillipsi-suedafrika-afrika-gruppe-blesbok-damaliscus-pygargus-phillipsi-south-africa-group/ZON-2448458/1
Bontebok https://www.alamy.com/bontebok-female-with-young-de-hoop-nature-reserve-western-cape-south-africa-africa-damaliscus-dorcas-dorcas-image228117439.html?imageid=373F25EB-E0E9-443A-8DD5-4194A60EEA24&p=205512&pn=1&searchId=e1c83791dbb28b2649d55bb669e0fbda&searchtype=0

Male:

Blesbok https://www.agefotostock.com/age/en/details-photo/blesbok-damaliscus-pygargus-phillipsi-adult-in-open-grassland-feeding-on-dry-grass-mountain-zebra-national-park-eastern-cape-south-africa-africa/ZI6-3207749/1
Bontebok https://www.alamy.com/bontebok-damaliscus-pygargus-damaliscus-dorcas-damaliscus-dorcas-dorcas-on-grassland-south-africa-bredasdorp-de-hoop-nature-reserve-image255390786.html

MALE HORNS PALER IN BLESBOK

Blesbok https://www.agefotostock.com/age/en/details-photo/blesbok-damaliscus-pygargus-phillipsi-mountain-zebra-national-park-south-africa-africa/RHA-764-3210/1
Bontebok https://www.gettyimages.com.au/detail/photo/bontebok-damaliscus-dorcas-at-bontebok-national-royalty-free-image/523049311?phrase=bontebok&adppopup=true

TAIL:
PALE STALK LONGER IN BONTEBOK
TASSEL PALER AND LONGER IN BLESBOK

Blesbok https://www.alamy.com/blesbok-damaliscus-pygargus-phillipsi-an-antelope-endemic-to-south-africa-and-swaziland-grazing-in-grassland-image344938371.html
Blesbok https://www.gettyimages.no/detail/photo/blesbok-antelopes-in-heat-royalty-free-image/547464562?adppopup=true
Bontebok https://www.dreamstime.com/stock-image-bontebok-antelope-image14126791

BACK-OF-EAR SHEENIER IN BLESBOK

Blesbok https://www.agefotostock.com/age/en/details-photo/blesboks-damaliscus-pygargus-phillipsi-two-adults-standing-in-open-grassland-alert-mountain-zebra-national-park-eastern-cape-south-africa-africa/ZI6-3207754/1
Bontebok https://www.inaturalist.org/observations/71049460

LOWER LEGS CLEARER IN BONTEBOK

Blesbok https://upload.wikimedia.org/wikipedia/commons/3/3a/Damaliscus_pygargus_phillipsi.jpg
Bontebok https://www.alamy.com/stock-photo-bontebok-antelope-17066360.html?imageid=AFA96455-2E25-41C8-91B0-1B7B94A1EA3C&p=4877&pn=1&searchId=abde0ec3b06a08943ffb523ff66f0db0&searchtype=0

RUMP CLEARER IN BONTEBOK

Blesbok https://www.istockphoto.com/photo/beautiful-blesbok-antelope-with-a-white-face-standing-in-the-green-field-gm1455330187-490697231?phrase=pics%20of%20a%20blesbok
Bontebok https://www.inaturalist.org/observations/57714646

PALE FACE MORE EXPANSIVE IN BLESBOK

Blesbok https://www.shutterstock.com/it/image-photo/antelope-wild-blesbok-blesbuck-lying-down-2223739223
Blesbok https://www.inaturalist.org/observations/70027286
Bontebok 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=10&search_type=pagination&get_facets=0&asset_id=271748733

TORSO:
VENTRAL PALE MORE EXTENSIVE IN BONTEBOK
BACK MORE CONTRASTING WITH FLANKS IN BONTEBOK

Blesbok https://www.agefotostock.com/age/en/details-photo/bontebok-blesbok-damaliscus-dorcas-stands-in-african-savanna-south-africa-eastern-cape-mountain-zebra-national-park/BWI-BS420963
Bontebok https://www.gettyimages.com.au/detail/photo/bontebok-damaliscus-dorcas-endemic-species-of-royalty-free-image/139810109?phrase=bontebok&adppopup=true

BACK-OF-FORELEG MORE DISTINCT IN BLESBOK

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
Bontebok https://www.gettyimages.com.au/detail/photo/bontebok-side-view-royalty-free-image/200214468-001?phrase=bontebok&adppopup=true
Bontebok https://www.gettyimages.com.au/detail/photo/bontebok-bushmans-kloof-private-game-reserve-royalty-free-image/925965224?phrase=bontebok&adppopup=true

INFANTS PALER IN BLESBOK

Blesbok https://www.shutterstock.com/it/image-photo/blesbok-mother-small-calf-leaning-against-91405400
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=410239969
Bontebok https://www.inaturalist.org/photos/40826355
Bontebok https://www.dreamstime.com/royalty-free-stock-image-mother-calf-blesbok-antelope-image21744916
Bontebok https://www.mediastorehouse.com.au/ardea-wildlife-pets-environment/danita-delimont/bontebok-rare-antelope-bushmans-25400655.html

INFANTILE FACIAL MARKINGS CLEARER IN BONTEBOK

Blesbok https://www.shutterstock.com/it/image-photo/blesbuck-newborn-baby-89983321
Blesbok https://stock.adobe.com/search/images?k=blesbok&asset_id=544432933
Bontebok https://www.shutterstock.com/it/image-photo/bontebok-calf-national-park-swellendam-western-2090432353
Bontebok https://www.inaturalist.org/observations/137997739
Bontebok https://upload.wikimedia.org/wikipedia/commons/e/e4/Bontebok_%28Damaliscus_pygargus_pygargus%29_young_..._%2832834333045%29.jpg
Bontebok https://www.flickr.com/photos/berniedup/50179826247

JUVENILE FACE DARKER IN BLESBOK

Blesbok https://www.agefotostock.com/age/en/details-photo/juvenile-blesbok-damaliscus-pygargus-phillipsi-mountain-zebra-national-park-south-africa-africa/RHA-764-4222/1
Blesbok https://www.agefotostock.com/age/en/details-photo/juvenile-blesbok-damaliscus-pygargus-phillipsi-mountain-zebra-national-park-south-africa-africa/RHA-764-4226/1
Bontebok https://www.gettyimages.com.au/detail/photo/bontebok-damaliscus-dorcas-at-bontebok-national-royalty-free-image/523049313?phrase=bontebok&adppopup=true

PALE SPOT ON FOREHEAD APPEARS AT >1 YEAR IN BLESBOK, VS 4 MONTHS IN BONTEBOK

Blesbok https://www.inaturalist.org/observations/21633759
Blesbok https://www.istockphoto.com/photo/young-blesbok-gm947259792-258650817
Blesbok https://www.agefotostock.com/age/en/details-photo/blesbok-damaliscus-pygargus-phillipsi-young-walking-in-open-grassland-alert-mountain-zebra-national-park-eastern-cape-south-africa-africa/ZI6-3207756
Bontebok https://es.123rf.com/photo_10162424_bontebok-damaliscus-dorcas-at-bontebok-national-park-in-south-africa.html
Bontebok https://www.shutterstock.com/it/image-photo/bontebok-antelope-calf-national-park-south-124597081
Bontebok https://www.shutterstock.com/it/image-photo/bontebok-antelope-female-calf-national-park-124597063

DISCUSSION

I have not featured the usual distinction, viz. that of a separation between the pale rostrum and the pale patch on the forehead (https://www.dreamstime.com/stock-image-blesbok-buck-head-image29082851).

This is because it has been overrated, given the individual variation and a tendency for coalescence with age in the blesbok.

Of the distinctions I have featured above, a few are well-known, but most have been previously underplayed - or completely overlooked.

Features which seem never to have been previously mentioned in the literature are those involving

  • the ears, tail-tassel, and expansion of pale on the face, and
  • the facial colouration of infants and juveniles.

Regarding the ears and tail-tassel, the previous oversight is understandable, because a particular search-image is needed. However, regarding expansion of pale on the face, the previous oversight is surprising. This is because dozens of photos of the blesbok on the Web, particularly from zoological gardens, show the phenomenon clearly.

The distinctions between the blesbok and the bontebok at the infantile and juvenile stages deserve further scrutiny, beyond the limited photographic evidence.

This is partly because ontogenetic differences - as well as those of sexual dimorphism - are likely to be particularly revealing, taxonomically.

Given this comprehensive list of phenological clues, it remains possible that the blesbok and the bontebok are different species, not merely subspecies.

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 16, 2023 06:12 TARDE por milewski milewski

Comentarios

Publicado por milewski hace 12 meses

The following shows that the expansion of pale on the face in adults of the blesbok can include the upper lips, which are normally brown:

https://zooinstitutes.com/animals/blesbok-zoo-liberec-8150.html

Publicado por milewski hace 12 meses

The following shows several noteworthy aspects of the colouration of the blesbok:

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

These are a) the gleaming pale on the back-of-ear, which constitutes an auricular flag, b) the conspicuousness of the pattern on the posterior surface of the upper foreleg, which constitutes an ulnar flag, c) the expansion of pale pelage on the face, d) the conspicuous pale on the lower legs, which constitutes a pedal flag, and e) the pattern on the side of the face in juveniles, which is surprisingly different from that in adults.

Publicado por milewski hace 12 meses
Publicado por milewski hace 12 meses

The following is a valuable collection of photos of the blesbok:

https://dewetswild.com/2016/06/23/blesbok/

Publicado por milewski hace 12 meses

The following contains several worthwhile photos of both bontebok and blesbok, showing in particular that the pelage of adult male bontebok features both gloss and sheen:

https://www.vw-worldtraveladventures.com/wildlife-encounters-1--2.html

Publicado por milewski hace 12 meses

The following mislabelled photo of male blesbok shows stocky body-form, long and pale horns, and pale on orbits above the eyes:

https://www.gettyimages.com.au/detail/photo/bontebok-adult-foraging-cape-of-the-good-hope-royalty-free-image/1470929206?phrase=bontebok&adppopup=true

Publicado por milewski hace 12 meses

Another difference is that the transverse ridges on the horns of males hardly extend to the posterior surface of the horns in the blesbok, whereas they clearly do so in the bontebok:

Blesbok

https://www.publicdomainpictures.net/en/view-image.php?image=237624&picture=back-of-head-of-blesbuck

Bontebok

https://www.istockphoto.com/photo/bontebok-gm1206627430-348069207?phrase=bontebok

This means that the horns differ altogether in four ways. The horns of the blesbok are longer (both sexes), stouter (males), paler (males), and differently ridged (males and possibly also females) than those of the bontebok.

SEXUAL DIMORPHISM IN HORNS OF BLESBOK

Female

https://www.istockphoto.com/photo/wild-male-african-antelope-blesbok-looks-at-the-camera-gm1223280959-359281865?phrase=bontebok

Male

https://www.gettyimages.com.au/detail/photo/close-up-profile-of-a-blesbok-royalty-free-image/71104633?phrase=blesbok&adppopup=truehttps://es.123rf.com/photo_149609314_el-blesbok-o-blesbuck-damaliscus-pygargus-phillipsi-que-se-ve-aqu%C3%AD-en-el-parque-nacional-mountain.html?vti=m20939y4w65u1s47ei-1-15

In the case of the BONTEBOK, the best illustration of the horns of the two sexes is https://www.inaturalist.org/observations/10791858.

Publicado por milewski hace 11 meses

The following two photos further illustrate the pallor of the infantile colouration in the blesbok. This individual 'infant' is 2-3 months old:

https://www.inaturalist.org/observations/150680502

For comparison, the following shows the 'infantile' colouration, at the same stage and age, in the bontebok:

https://www.alamy.com/stock-photo-a-bontebok-mother-and-her-calf-foraging-in-fynbos-in-southern-africa-141498699.html?imageid=50F467B2-84B3-4554-8E26-126FAB4332D1&p=291902&pn=1&searchId=e1c83791dbb28b2649d55bb669e0fbda&searchtype=0

Publicado por milewski hace 11 meses

The following shows that the white patch on the forehead appears only near adolescence in the blesbok: https://www.inaturalist.org/observations/21633759.

By comparison, this patch appears early in the juvenile colouration in the case of the bontebok:

https://es.123rf.com/photo_10162424_bontebok-damaliscus-dorcas-at-bontebok-national-park-in-south-africa.html.

Publicado por milewski hace 11 meses
Publicado por milewski hace 11 meses

@simontonge

Another difference between the blesbok and the bontebok is in the importance of the preorbital glands.

In the blesbok, the preorbital glands are larger in males than in females. In territorial males, tear-like smudges of the secretion stain the whitish of the facial bleeze (https://www.alamy.com/blesbok-ram-south-africa-image461169315.html?imageid=001C257D-17B9-40A6-B84A-D41BBD03388A&p=1836369&pn=1&searchId=e677b66985946bfb4aba06bac507ed3a&searchtype=0 and https://www.alamy.com/blesbok-ram-south-africa-image459385879.html?imageid=4BF9B170-E91E-4FD8-A8A0-0D9006664F77&p=1836369&pn=1&searchId=e677b66985946bfb4aba06bac507ed3a&searchtype=0 and https://www.alamy.com/blesbok-ram-south-africa-image461119047.html?imageid=6474ECAD-398E-45D2-9AB9-CC1A04F5F84D&p=1836369&pn=1&searchId=e677b66985946bfb4aba06bac507ed3a&searchtype=0).

In the bontebok, there is no staining of the white of the facial bleeze.

Furthermore, in the blesbok, the horns accumulate this secretion in the following way.

First, the secretion is deposited on grass stalks, by lowering the face to poke and rub the stalk into the glandular orifice. Then, the face, forehead, and horns are anointed by being rubbed on the stalk, transferring the secretion. In the case of the horns, the substance may form thick layers between the annuli.

This behaviour of rubbing and anointing is poorly-developed in the bontebok, in which the face, forehead, and horns are not stained or layered with the secretion.

David (1970) suggested that the preorbital gland has lost its functional significance of territorial demarcation in the bontebok, in which the anointing behaviour seems merely relictual.

REFERENCES

David J H M (1970) The behaviour of the bontebok, Damaliscus dorcas dorcas, with special reference to territorial behaviour. MSc thesis, University of Cape Town. 119 pages.

https://www.researchgate.net/publication/240960600_The_Behaviour_of_the_Bontebok_Damaliscus_dorcas_dorcas_Pallas_1766_with_Special_Reference_to_Territorial_Behaviour

Lynch C D (1971) A behavioural study of blesbok, Damaliscus dorcas phillipsi, with special reference to territoriality. MSc thesis, University of Pretoria. 102 pages.

https://www.abebooks.com/first-edition/Behavioural-Study-Blesbok-Damaliscus-Dorcas-Phillipsi/30652735461/bd

Publicado por milewski hace 10 meses

I tested my view that the horns are longer in the blesbok than in the bontebok, by consulting the world record lengths:

https://rowlandward.org/wp-content/uploads/2021/02/01-African-Minimums-and-World-Records.pdf

Blesbok: 52.4 cm

https://blog.bookyourhunt.com/blesbok-and-blesbok-hunting/

Bontebok: 43.6 cm

https://www.facebook.com/BontebokSA/posts/bontebok-record-toppedthe-roland-ward-records-of-big-game-26th-edition-shows-the/2195789387309769/

This confirms that the maximum length of the horns in the blesbok exceeds that in the bontebok by 9 cm.

Publicado por milewski hace 10 meses

The following (https://www.inaturalist.org/observations/174515485), of what seems to be an elderly male individual, is the only clear photo I have found of pale annuli on the horns of the bontebok.

For comparison:
Then following (https://www.alamy.com/stock-photo-close-up-profile-of-a-blesbok-damaliscus-albifrons-14685442.html) is typical of adult males of the blesbok.

Publicado por milewski hace 7 meses

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