Which ruminant is born with the most conspicuous facial pattern of colouration? part 1: hippotragin and alcelaphin bovids

@tandala @simontonge @paradoxornithidae @tonyrebelo @jeremygilmore @oviscanadensis_connerties @davidbygott @dejong @michalsloviak @christiaan_viljoen @capracornelius @gigilaidler @maxallen

Various ruminants have bold facial markings in both sexes, helping to make the animals adaptively conspicuous.

An example is https://www.sa-venues.com/wildlife/wildlife_roan_antelope.php.

However, in most ruminants, infants hide for a period (https://www.jstor.org/stable/3061529). This makes it adaptive for the colouration to be inconspicuous at birth.

In this Post, I examine four species of bovids with boldly-marked faces, and I illustrate the colouration in infancy, relative to that in adulthood.

These are

  • two hippotragins, in which infants hide, and
  • two alcelaphins, in which infants accompany their mothers continually right from the start.

ORYX GAZELLA (https://www.inaturalist.org/taxa/42308-Oryx-gazella)

In this species of hippotragin bovid, adults possess a facial bleeze.

At birth, the facial pattern is not plain. However, it is so nebulous that it is certainly inconspicuous (https://upload.wikimedia.org/wikipedia/commons/0/05/Oryx_gazella_3_-_Gemsbok_cub.JPG).

As infants grow, the facial pattern, like the horns, develops precocially.

https://www.mindenpictures.com/stock-photo-gemsbok-oryx-gazella-female-with-two-calves-namibrand-reserve-namib-naturephotography-image90799302.html

https://www.zoochat.com/community/media/gemsbok-calf-whipsnade-04-jul-2014.262375/

https://www.alamy.com/gemsbok-oryx-gazella-calf-image4734981.html

https://www.alamy.com/gemsbok-oryx-gazella-calf-image4734984.html

HIPPOTRAGUS EQUINUS (https://www.inaturalist.org/taxa/42332-Hippotragus-equinus)

This hippotragin bovid probably qualifies for a facial bleeze in adults (https://www.inaturalist.org/observations/138018015).

The relationship of infants to adults is similar to that in Oryx gazella.

However, the pattern is so precocial that an argument can be made for at least a facial flag in infants. If so, H. equinus may exemplify the presence at birth of a facial flag, in ruminants.

https://www.agefotostock.com/age/en/details-photo/roan-antelope-hippotragus-equinus-calf-standing-in-dry-woodland-fatalah-reserve-senegal-january/FHR-10028-00039-849

https://es.123rf.com/photo_27725369_roan-antelope-hippotragus-equinus-calf.html

https://www.zoochat.com/community/media/roan-antelope-calf.55666/

https://www.zoochat.com/community/media/roan-antelope-calf.145764/

https://www.inaturalist.org/observations/33354786

DAMALISCUS PYGARGUS (https://www.inaturalist.org/taxa/42275-Damaliscus-pygargus)

This species of alcelaphin bovid certainly qualifies for a facial bleeze in adults.

As in the hippotragins shown above, infants are born with a trace of the facial pattern of adults. However, the relative placement of dark/pale is puzzlingly inverted (see https://www.inaturalist.org/journal/milewski/76336-adaptive-colouration-in-the-bontebok-damaliscus-pygargus-pygargus-part-2-infants-juveniles-and-adolescents# and https://www.inaturalist.org/journal/milewski/75995-adaptive-colouration-in-the-blesbok-damaliscus-pygargus-phillipsi-part-2-infants-juveniles-and-adolescents#).

https://www.zooborns.com/zooborns/2012/04/meet-blossom-the-blesbok-calf-born-at-belfast-zoo.html

https://www.dreamstime.com/stock-photos-blesbok-antelope-calf-standing-protectively-next-to-s-baby-image36296983

CONNOCHAETES ALBOJUBATUS (https://www.inaturalist.org/observations?taxon_id=525438)

Unlike the three species shown above, the facial colouration of Connochaetes albojubatus is ambivalent in its boldness. However, I include it here because it is the form of wildebeest with the most conspicuous facial colouration.

In the case of wildebeests, the patterns tend to be obfuscated by

  • the confusing complex of species/subspecies, in which various aspects/features of colouration vary in emphasis rather than presence/absence,
  • sheen/antisheen and other effects of illumination, and
  • individual variation.

However, in adults of C. albojubatus, the cheeks tend to be clearer and paler than in other forms of wildebeest, and equally sheeny. This means that C. albojubatus is the wildebeest most likely to qualify for a facial flag.

What is noteworthy is that the facial pattern is also more preocial in C. albojubatus (https://inaturalist.ca/observations/110949669) than in other wildebeests, with the possible exception of another form with a pale beard, viz. Connochaetes mearnsi.

Adults:

The facial pattern in adults of C. albojubatus is, owing to individual variation and the effects of illumination, not consistent enough to qualify for a bleeze. Its maximum expression is seen in https://www.dreamstime.com/stock-photo-young-male-antelope-wildebeest-standing-marshy-lowland-sunn-sunny-afternoon-image89889139.

This pattern - which does qualify as a facial flag - consists of

  • a consistently black rostrum,
  • a pale beard, located close enough to the dark muzzle to provide pale/dark contrast, and
  • cheeks that are usually pale, sheeny, and free of brindling.

https://www.alamy.com/single-wildebeest-in-amboseli-national-park-image362840009.html

https://www.alamy.com/eastern-white-bearded-wildebeest-connochaetes-taurinus-albojubatus-also-brindled-gnu-antelope-in-eastern-and-southern-africa-belongs-to-bovidae-wi-image446124408.html

https://www.alamy.com/stock-photo-eastern-white-bearded-wildebeest-connochaetes-taurinus-albojubatus-57729409.html

https://www.dreamstime.com/blue-wildebeest-wander-grasslands-tsavo-east-park-kenay-image208617369

https://www.alamy.com/blue-wildebeest-connochaetes-taurinus-males-fighting-amboseli-n-p-image443376.html

https://www.dreamstime.com/wildebeest-gnu-portrait-standing-savannah-africa-image155054207

https://inaturalist.ca/observations/5784993

https://www.alamy.com/single-blue-wildebeest-white-bearded-wildebeest-or-brindled-gnu-connochaetes-taurinus-running-across-grassland-of-the-african-savannah-kenya-image240812175.html

https://www.dreamstime.com/wildebeest-gnu-portrait-standing-savannah-africa-image155054207

https://inaturalist.ca/observations/102105372

https://www.dreamstime.com/stock-photos-three-wildebeest-run-image16846173

https://www.dreamstime.com/stock-photo-wildebeest-blue-gnu-connochaetes-taurinus-amboseli-kenya-image67014218

https://www.dreamstime.com/closeup-wildebeest-browsing-closeup-wildebeest-scientific-name-connochaetes-taurinus-nyumbu-swaheli-image-taken-image108980595

https://www.dreamstime.com/royalty-free-stock-photos-wildebeest-connochaetes-taurinus-single-mammal-ground-tanzania-image35926688

https://www.dreamstime.com/royalty-free-stock-photos-wildebeest-image7626258

https://www.alamy.com/eastern-white-bearded-wildebeest-connochaetes-taurinus-albojubatus-also-brindled-gnu-antelope-in-eastern-and-southern-africa-belongs-to-bovidae-wi-image446125271.html

https://zooinstitutes.com/animals/eastern-white-bearded-wildebeest-almaty-zoo-26267.html

https://inaturalist.ca/observations/19542826

Infants:

There are too few photos available to assess individual variation. However, the black rostrum tends to be fully expressed at birth.

The cheeks of infants are not as obviously pale as in most adults, and the pale beard (although precocial) is inconspicuous at birth.

However, a previously overlooked aspect is that, unlike adults, the blackish of the face extends ventral to the eyes (https://www.agefotostock.com/age/en/details-photo/wildebeest-calf-in-plains-amboseli-national-park-kenya/AAM-AAES71424). The facial insignia are thus, in a limited sense, better-developed in infants than in adults, making wildebeests unusual among ruminants.

It is noteworthy that Damaliscus pygargus, another alcelaphin, also has a distinction between infants and adults in the colouration of the orbits. The difference is that, in infants of D. pygargus, the orbits are noticeably pale, not noticeably dark (https://www.zooborns.com/zooborns/antelope/).

https://www.dreamstime.com/stock-photo-newborn-wildebeest-amboseli-park-kenya-mother-baby-image76472324

https://www.flickr.com/photos/sdzooglobal/9270596187

Scroll in https://movementoflife.si.edu/species/wildebeest/

https://www.gettyimages.co.uk/detail/news-photo/boston-ma-a-baby-wildebeest-born-in-the-past-week-on-news-photo/1371566822?adppopup=true

https://www.gettyimages.co.uk/detail/news-photo/boston-ma-a-baby-wildebeest-born-in-the-past-week-on-news-photo/1371566810?adppopup=true

https://www.dreamstime.com/stock-photo-newborn-wildebeest-amboseli-park-kenya-mother-baby-rest-herd-background-image76472453

Scroll in https://www.zoonewengland.org/franklin-park-zoo/our-animals/mammals/hoofed/white-bearded-wildebeest/

https://inaturalist.ca/observations/106811995

https://www.jhpostcards.com/products/white-bearded-wildebeest-riga-zoo-animals-1980-latvia-ussr-unused

Juveniles:

The facial pattern in juveniles of C. albojubatus is as conspicuous as that in adults (https://www.dreamstime.com/stock-photo-big-wildebeest-migration-african-safari-amboseli-national-park-kenia-image84361100).

As growth proceeds, the pelage below the eye loses its black pigmentation (https://inaturalist.ca/observations/6812082).

https://www.alamy.com/stock-photo-part-of-a-herd-of-blue-wildebeest-connochaetes-taurinus-grazing-126164867.html

https://www.alamy.com/herd-of-common-wildebeests-walking-in-dry-grassland-on-summer-day-in-amboseli-national-park-kenya-image502860670.html

https://www.alamy.com/blue-wildebeest-connochaetes-taurinus-amboseli-national-park-kenya-image62676645.html

https://www.alamy.com/eastern-white-bearded-wildebeest-connochaetes-taurinus-albojubatus-also-brindled-gnu-antelope-in-eastern-and-southern-africa-belongs-to-bovidae-wi-image446124965.html

https://www.alamy.com/eastern-white-bearded-wildebeest-connochaetes-taurinus-albojubatus-also-brindled-gnu-antelope-in-eastern-and-southern-africa-belongs-to-bovidae-wi-image446125038.html

https://www.alamy.com/wildebeest-in-the-national-park-tsavo-east-tsavo-west-and-amboseli-in-kenya-image483241293.html?imageid=FE32865D-C28D-4A48-A37B-54D64A5294CF&p=774865&pn=1&searchId=1ded7a829c6fd29f9a553cf0e1e2072e&searchtype=0

DISCUSSION

I know of no ruminant that is born with a facial bleeze.

A facial flag at birth seems plausible in Hippotragus equinus. This would be consistent with

Since infants of H. equinus hide initially, it is unknown how the precociality of the facial pattern is adaptive. Even in adults, the adaptive value of bold facial colouration in hippotragins remains poorly understood.

What is more complex, and even more intriguing, is the ontogeny of the facial pattern in certain alcelaphins.

The facial pattern in infants of wildebeests ranges from inconspicuous in Connochaetes gnou (https://www.zooborns.com/zooborns/wildebeest/ and https://www.irishnews.com/magazine/daily/2019/08/27/news/rare-baby-wildebeest-born-at-newquay-zoo-1696156/ and scroll to fifth photo in https://africafreak.com/black-wildebeest) to conspicuous in C. albojubatus.

The remaining forms are intermediate, with Connochaetes mearnsi and Connochaetes taurinus mattosi (https://www.dreamstime.com/stock-photo-blue-wildebeest-side-view-mosi-oa-tunya-nation-park-zambia-africa-image61435936) apparently exceeding Connochaetes taurinus taurinus, C. t. cooksoni, and C. t. johnstoni.

For infants of wildebeests to have conspicuous colouration seems consistent with extreme adaptation for gregariousness in open environments, and extreme precociality at birth.

However, it remains unexplained why wildebeests vary in this respect.

It remains possible that C. mearnsi (see first comment below) exceeds C. albojubatus in the consistent boldness of the facial pattern in infants. This depends on further photographic evidence.

Given that, in adults, the facial pattern in C. mearnsi is less conspicuous than that in C. albojubatus, this might make C. mearnsi unique among ruminants, in having a facial pattern more conspicuous at birth than in adulthood.

In this context, I remind readers that infants of wildebeests also possess a pedal flag (https://www.dreamstime.com/stock-photo-blue-wildebeest-connochaetes-taurinus-young-calf-playing-rain-kruger-national-park-south-africa-image60301989), absent in adults.

Publicado el marzo 13, 2023 09:23 TARDE por milewski milewski

Comentarios

CONNOCHAETES MEARNSI

Unlike Connochaetes albojubatus, adults of Connochaetes mearnsi lack clear, plain cheeks:

https://www.dreamstime.com/royalty-free-stock-photo-blue-wildebeest-image1456745

https://www.dreamstime.com/royalty-free-stock-photography-wildebeest-image1139237

https://www.dreamstime.com/royalty-free-stock-photo-wildebeest-savannah-image29682965

The infants of C. mearnsi resemble those of C. albojubatus:

https://www.dreamstime.com/blue-wildebeest-newborn-calf-blue-wildebeest-connochaetes-taurinus-newborn-calf-ngorongoro-crater-national-park-tanzania-image161274444

https://www.gettyimages.co.uk/detail/photo/wildebeest-baby-walking-africa-royalty-free-image/989663832?adppopup=true

https://www.istockphoto.com/photo/juvenile-wildebeest-gm1387356226-445320660?phrase=wildebeest%20fur%20close%20up

The following, of C. mearnsi, show mothers and infants together:

https://www.dreamstime.com/antelope-gnu-two-little-babies-image147089171

https://www.dreamstime.com/stock-images-blue-wildebeest-mother-foal-image24243134

https://www.gettyimages.co.uk/detail/photo/wildebeest-and-its-baby-side-view-real-love-royalty-free-image/167157218?adppopup=true

https://www.dreamstime.com/stock-photo-wildebeest-national-reserve-africa-kenya-image46061171

https://www.dreamstime.com/stock-photo-wildebeest-calf-ngorongoro-conservation-area-tanzania-crater-image86607170

https://www.dreamstime.com/black-bearded-wildebeest-calf-sun-serengeti-national-park-tanzania-black-bearded-wildebeest-calf-image138715372

https://www.dreamstime.com/stock-photo-wildebeest-calf-connochaetes-taurinus-image19692550

http://www.safari-club.co.uk/photo-galleries/kenya-familiarisation-trip-2010/dsc_0062/

Publicado por milewski hace más de 1 año

Shift

Unusually clear illustration of pedal flag in Giraffa tippelskirchi tippelskirchi:

https://www.alamy.com/stock-photo-a-blue-wildebeest-connochaetes-taurinus-with-masai-giraffe-giraffa-24193547.html

Publicado por milewski hace más de 1 año

The following illustrates the conspicuous whole-figure dankness at distance in wildebeests, in this case Connochaetes mearnsi:

https://www.dreamstime.com/stock-photo-cheetah-african-plains-image2413620

Publicado por milewski hace más de 1 año

Connochaetes taurinus mattosi:

In this subspecies, the colouration on the head is more conspicuous than that of Connochaetes taurinus taurinus.

This is partly because of the fullness of the dark beard, and partly because the somewhat sheeny cheeks tend to free of brindling (https://www.dreamstime.com/blue-wildebeest-gnu-side-portrait-standing-warm-soft-morning-light-kgalagadi-connochaetes-taurinus-image187871817).

However, C. t. mattosi falls short of qualifying for either a facial bleeze or a facial flag.

Infants probably exceed those of C. t. taurinus in the darkness of the face. However, the colouration of the head in infants is not as conspicuous as it is in Connochaetes albojubatus.

https://www.gettyimages.co.uk/detail/news-photo/wildebeest-mother-with-a-newly-born-baby-on-the-floodplains-news-photo/1199698479?adppopup=true

https://www.agefotostock.com/age/en/details-photo/wildebeest-or-gnu-with-a-newly-born-baby-near-the-sesriem-canyon-in-the-sossusvlei-area-namib-naukluft-national-park-in-namibia/ZM4-3478603

https://www.dreamstime.com/stock-photo-wildebeest-natural-habitat-blue-connochaetes-taurinus-etosha-national-park-namibia-image79657259

https://www.dreamstime.com/young-blue-wildebeest-calf-connochaetes-taurinus-kalahari-desert-south-africa-blue-wildebeest-calf-kalahari-desert-image112359328

https://www.dreamstime.com/blue-wildebeest-walking-dry-grass-morning-sunlight-moremi-okavango-delta-botswana-blue-wildebeest-walking-grass-image198812255

https://www.dreamstime.com/stock-photo-blue-wildebeest-calves-two-young-connochaetes-taurinus-kalahari-south-africa-image78888697

https://www.dreamstime.com/stock-photo-blue-wildebeest-calf-young-connochaetes-taurinus-kalahari-south-africa-image72782178

https://www.dreamstime.com/stock-photo-blue-wildebeest-calf-young-connochaetes-taurinus-south-africa-image42229647

https://www.dreamstime.com/single-wildebeest-walking-makgadikgadi-pan-dry-land-makgadikgad-botswana-africa-image160270606

https://www.dreamstime.com/stock-photos-black-wildebeest-antelope-africa-shaggy-fur-horns-image39344113

Publicado por milewski hace más de 1 año

@paradoxornithidae @matthewinabinett

The black wildebeest (Connochaetes gnou) exemplifies the general syndrome among wildebeests, which is that their conspicuous features of colouration tend to be rather nebulous.

The overall conspicuousness of the black wildebeest is owing to the darkness of most of the figure. The tail is pale, which potentially enhances conspicuousness by contrasting with the darkness of the body.

However, any perusal of photos of this species shows that the tail is incompletely depigmented, and/or dusty, making it not particularly conspicuous in most views.

The full potential of the tail, in flagging the figure, is seen in a minor percentage of the photos. However, it remains uncertain whether this results from sheen, cleanliness (e.g. after rain), individual variation, or all three factors.

As a result, I suggest that the paleness of the tail of the black wildebeest qualifies as a caudal flag, but not a caudal bleeze. The tail is proportionately large enough to produce a bleeze, but its paleness is too ambivalent, particularly when the whole figure and the tail are stationary.

https://www.dreamstime.com/royalty-free-stock-images-black-wildebeest-image21510259

https://www.dreamstime.com/stock-photos-black-wildebeest-image26736233

https://www.dreamstime.com/stock-photo-black-wildebeest-connochaetes-gnou-amakhala-game-reserve-eastern-cape-south-africa-image51205489

https://www.dreamstime.com/black-wildebeest-grassland-south-africa-connochaetes-gnou-open-mokala-national-park-image268339114

https://www.dreamstime.com/stock-photo-blue-wildebeest-green-grass-landscape-wildebeests-also-called-gnus-wildebai-genus-antelopes-connochaetes-image76021783

https://www.dreamstime.com/stock-photo-black-wildebeest-pair-connochaetes-gnou-south-africa-image83687537

https://www.dreamstime.com/stock-photo-black-wildebeest-connochaetes-gnou-stood-mountain-grassland-south-africa-image43966917

https://www.dreamstime.com/black-wildebeest-south-african-plains-green-landscape-photographed-africa-image164824270

https://www.dreamstime.com/stock-photo-black-wildebeest-male-standing-open-grass-plain-image84425318

https://www.dreamstime.com/stock-photo-black-wildebeest-grazing-wild-meadow-south-africa-image40997849

https://www.dreamstime.com/black-wildebeest-grassland-south-africa-connochaetes-gnou-open-mountain-zebra-national-park-image139531492

https://www.dreamstime.com/black-wildebeest-walking-grassland-connochaetes-gnou-mountain-zebra-national-park-south-africa-image258403648

https://www.dreamstime.com/stock-image-close-up-black-wildebeest-connblack-wildebeest-image27123161

Publicado por milewski hace más de 1 año
Publicado por milewski hace más de 1 año

The following is attributed, by implication, to Connochaetes mearnsi. However, I suspect that it is Connochaetes albojubatus.

https://www.dreamstime.com/stock-photography-wildebeest-national-park-serengeti-tanzania-africa-image31185862

Publicado por milewski hace más de 1 año

shift to my Post suggesting that Connochaetes taurinus mattosi is derived from hybridisation between Connochaetes taurinus taurinus and Connochaetes gnou:

https://www.dreamstime.com/wildebeest-oryx-gazella-gemsbok-de-namib-desert-near-solitaire-namibia-walking-across-plains-image109032492

Publicado por milewski hace más de 1 año

The following contains a clear photo of facial flag in Connochaetes albojubatus:

https://fossilrim.org/jernigan-discusses-wildebeest-at-fossil-rim/

Publicado por milewski hace más de 1 año

@paradoxornithidae

The following (https://www.dreamstime.com/female-zebra-running-fast-leaving-dust-across-amboseli-plains-kenya-adult-galloping-wildebeest-herd-walking-background-image194188688) inadvertently shows two flags, belonging to two different ungulates, side-by-side in a single photo.

In the foreground, we see the auricular flag of Equus quagga (in this case a 'maneless' form of subspecies boehmi). In the background, we see the facial flag of Connochaetes albojubatus (in this case a juvenile individual, probably about two years old).

It seems to be merely coincidental that the form of plains zebra with the clearest auricular flag, and the type of wildebeest with the clearest facial flag, occur together in eastern Kenya (in this case in Amboseli National Park).

In this zebra, the auricular flag consists of the clear white posterior surface of the ear pinnae, offset by a small subterminal patch of blackish. This gleams conspicuously against the overall striping of the head and neck, with which it is so incongruent that the display is effective despite the small size of the ears.

In this wildebeest, the facial flag (viewed here in full profile) consists of the blackish front of the head, from the crown down to the muzzle, offset by the pale side of the head, plus the pale beard. The dark/pale contrast is not as stark as in the case of the zebra, but the display is effective because of the large size of the head.

Please bear in mind that, by definition, flags (in the context of animal colouration) are activated by motion. Typically, this motion is of the particular body-part involved. However, motion of the whole figure (as in this case) also applies.

Publicado por milewski hace alrededor de 1 año

Connochaetes gnou:

https://www.dreamstime.com/black-wildebeest-connochaetes-gnou-female-young-image196305454

Infants of the black wildebeest, at least in the case of some individuals, have a precocially dark face. However, this is inconspicuous, because there is no contrast with pale on the head.

What is more likely to be conspicuous, as shown in this photo, is the pedal flag, consisting of pale feet.

Publicado por milewski hace alrededor de 1 año

Agregar un comentario

Acceder o Crear una cuenta para agregar comentarios.