A comparison of the goitred gazelle and the springbok

@tonyrebelo @jeremygilmore @jwidness @oviscanadensis_connerties @tandala @beartracker @matthewinabinett @michalsloviak @capracornelius @colin25 @davidbygott @giorginatsvlishvili @koenbetjes

Also see https://www.inaturalist.org/journal/milewski/53340-differences-among-gazelles-in-the-structure-and-function-of-the-tail#

Two gazelles make for an obvious comparison, because they live on similar semi-arid plains in opposite hemispheres.

These are

Adults, while foraging, can hardly hide in these exposed environments (except for the goitred gazelle in saxaul 'forest' in winter, see comment below).

Because the two species are species are related, as antilopin bovids, and because they live in similar ecosystems, they might be expected to have similar adaptive colouration.

And indeed the two species are similar enough to be confused at first glance (https://www.inaturalist.org/observations/55091275 and https://www.inaturalist.org/observations/143913081).

Both have

However, there are three main differences, viz.

In the following account, I have used photos from not only the Iranian region and South Africa, but also - owing to the scarcity of appropriate images - the rest of the distribution of both species.

STATIONARY:

A puzzling difference in adaptive colouration is that the goitred gazelle tends to blend into its surroundings, whereas the springbok tends to stand out even at a distance, and even when motionless.

What makes the springbok so conspicuous is its boldly dark flank-band, offset by white highlights on the face, rump, flanks, and upper legs (see https://www.inaturalist.org/observations/85319775 and https://www.inaturalist.org/observations/70140445 and https://www.inaturalist.org/observations/76488627 and https://www.inaturalist.org/observations/70682974 and https://www.inaturalist.org/observations/65916271).

In the goitred gazelle, the basic pattern is similar. However, it is toned down to a semblance of camouflage (https://commons.wikimedia.org/wiki/File:Ceyran.jpg and https://www.dreamstime.com/goitered-gazelle-jeyran-field-wildlife-nature-reserve-goitered-gazelle-jeyran-field-wildlife-nature-reserve-field-image216752540 and video in https://animalia.bio/goitered-gazelle and https://www.shutterstock.com/da/image-photo/gazella-subgutturosa-goitered-gazelle-1155749653).

Both the goitred gazelle and the springbok can have conspicuously pale faces, and in both species the paleness on the face develops as the animal grows.

However, the pale face is not as consistent among adult individuals in the goitred gazelle as in the springbok (please see https://www.inaturalist.org/journal/milewski/75660-the-facial-flag-of-the-springbok-antidorcas-marsupialis#).

In the goitred gazelle the pale face is associated more with the male (https://www.shutterstock.com/it/image-photo/gazella-subgutturosa-goitered-gazelle-1155749656
https://www.mediastorehouse.com.au/nature-picture-library/2020-august-highlights/goitered-black-tailed-gazelle-gazella-20172891.html and https://www.shutterstock.com/it/image-photo/gazella-subgutturosa-goitered-gazelle-1155749653) than with the female.

Even in mature males (https://www.dreamstime.com/persian-goitered-gazelle-male-female-background-latin-name-gazella-subgutturosa-persian-goitered-gazelle-male-image133088223), some individuals retain the inconspicuous pattern on the face.

MILD ALARM:

The goitred gazelle signals mild alarm by erecting the tail (https://www.inaturalist.org/observations/130903897 and https://www.inaturalist.org/observations/77627182 and https://www.inaturalist.org/observations/796456 and https://www.agefotostock.com/age/en/details-news-photo/200607-altay-june-7-2020-goitered-gazelles-are-seen-at-the-kalamayli-nature-reserve-northwest-china-s-xinjiang-uygur-autonomous-region-june-6/HTS-ZB950_351940_0069/1).

The dark tail is offset by the white buttocks (https://www.pond5.com/stock-footage/item/130905132-herd-goitered-gazelles-running-desert-001 and https://www.pond5.com/stock-footage/item/130905144-herd-goitered-gazelles-running-desert-004).

There is no analogous display in the springbok, which lacks a caudal flag.

STOTTING:

Both species greet scanning predators with stotting displays. However, these accentuate the differences in colouration.

The goitred gazelle stots by bouncing up and down with its black tail erect (https://www.istockphoto.com/video/running-goitered-gazelle-gm473245311-26196643 and video in https://discover.hubpages.com/education/Goitered-Gazelle-History-Facts-and-Efforts-to-Recover-It and https://www.diana-hunting.com/game/goitered-gazelle).

By contrast, the springbok has an extreme performance. It bounces while blazening an uniquely extended white double-crest that is normally folded invisible on the back, rump and buttocks (https://www.inaturalist.org/observations/134967922
and https://www.youtube.com/watch?v=jMIiB9DnRXg and https://www.atlasobscura.com/articles/watch-this-gazelle-spring-across-the-african-savanna-like-a-pogo-stick and https://www.gettyimages.ca/detail/photo/springbuck-jumping-in-the-air-kgalagadi-nature-royalty-free-image/976918234?adppopup=true).

However, the springbok does not always activate the crest while stotting:
https://www.gettyimages.ca/detail/photo/lone-springbok-on-plain-royalty-free-image/71587160?adppopup=true
https://www.alamy.com/stock-photo-springbok-antelope-antidorcas-marsupialis-jumping-south-africa-72687711.html?imageid=96BE87F5-378F-4276-9015-329CDA50F252&p=70019&pn=1&searchId=1ad475034542f64d7d819bbce4f5e724&searchtype=0

FLEEING:

Whereas the goitred gazelle flees and stots with its tail rigidly erect (see https://www.inaturalist.org/observations/504792 and https://www.inaturalist.org/observations/38272914), the springbok never even raises its tail to the horizontal while fleeing (see https://www.alamy.com/springbok-antidorcas-marsupialis-running-namibia-etosha-national-park-image151881858.html) or stotting (see https://www.shutterstock.com/da/image-photo/pronking-springbok-37655779 and https://elements.envato.com/springbok-pronking-in-the-grass-X6ZPTS2).

This difference makes sense partly because in the springbok the dark tassel is too small to add much to the display (https://www.inaturalist.org/observations/73197549), and the base of the tapering tail is less flexible than in the goitred gazelle (compare https://www.alamy.com/tail-end-of-goitered-gazelle-gazella-subgutturosa-image211285398.html with https://www.alamy.com/springbuck-springbok-antidorcas-marsupialis-herd-from-behind-namibia-image5449818.html).

The following show the goitred gazelle fleeing:
https://www.agefotostock.com/age/en/details-news-photo/200314-xilingol-march-14-2020-photo-taken-on-march-13-2020-in-sunite-right-banner-of-xilingol-league-north-china-s-inner-mongolia-autonomous/HTS-ZB950_348151_0039/1
https://www.inaturalist.org/observations/65033568
https://www.inaturalist.org/observations/139354386
https://www.inaturalist.org/observations/32798804
https://www.inaturalist.org/observations/17020189
https://www.inaturalist.org/observations/504792
https://www.flickr.com/photos/130113460@N03/41071430952
https://www.flickr.com/photos/wildlife_of_mongolia/14188610261
https://www.flickriver.com/photos/132934880@N02/48884899921/
https://www.shutterstock.com/it/image-photo/goitered-gazelle-jeyran-field-wildlife-nature-1972172735
https://www.naturepl.com/stock-photo-male-goitered-gazelle-gazella-subgutturosa-running-badkhyz-reserve-image01445599.html
Scroll to fourth photo in https://birdingmongolia.wordpress.com/2020/04/01/jargalant-mountains/

It is only when the fleeing is at full speed that the tail is lowered:
https://www.inaturalist.org/observations/612402
https://www.agefotostock.com/age/en/details-news-photo/200314-xilingol-march-14-2020-photo-taken-on-march-13-2020-in-sunite-right-banner-of-xilingol-league-north-china-s-inner-mongolia-autonomous/HTS-ZB950_348151_0049/1
https://www.inaturalist.org/observations/8282800
https://www.gettyimages.com.au/detail/photo/goitered-gazelle-also-known-as-gazella-subgutturosa-royalty-free-image/933847462
https://www.agefotostock.com/age/en/details-news-photo/200314-xilingol-march-14-2020-xinhua-photo-taken-on-march-13-2020-in-sunite-right-banner-of-xilingol-league/HTS-ZB950_348151_0052/1
https://www.mindenpictures.com/stock-photo-black-tailed-gazelle-gazella-subgutturosa-male-running-gobi-desert-naturephotography-image90136801.html

The following show the springbok fleeing:
https://www.gettyimages.ca/detail/photo/side-view-of-dog-running-on-field-arad-romania-royalty-free-image/1457183102?adppopup=true
https://www.inaturalist.org/observations/131774461
https://www.inaturalist.org/observations/112872508
https://www.inaturalist.org/observations/86033851
https://www.inaturalist.org/observations/73628357
https://www.inaturalist.org/observations/11258709
https://www.inaturalist.org/observations/11304134
https://www.inaturalist.org/observations/10957814
https://www.inaturalist.org/observations/1181659
https://www.gettyimages.ca/detail/news-photo/springboks-running-on-plains-kgalagadi-transfrontier-park-news-photo/144860225?adppopup=true
https://www.gettyimages.ca/detail/news-photo/herd-of-sprinbok-grazing-on-savanna-plane-at-etosha-news-photo/481582125?adppopup=true
https://www.gettyimages.ca/detail/photo/northern-region-of-the-namib-desert-namibia-royalty-free-image/80254736?adppopup=true

Unlike the goitred gazelle, the springbok sometimes bounds. This is an action different from stotting:
https://www.gettyimages.ca/detail/photo/springbok-leaping-central-kalahari-royalty-free-image/dv029121?adppopup=true
https://www.inaturalist.org/observations/25949
https://www.gettyimages.ca/detail/photo/springbok-leaping-central-kalahari-royalty-free-image/dv029121?adppopup=true
https://www.gettyimages.ca/detail/photo/springbok-running-royalty-free-image/125528069?adppopup=true

INTERPRETATION

What is the adaptive significance of these differences between the goitred gazelle and the springbok?

Consider the different regimes of natural predation in the Iranian region and South Africa. Here, the counterintuitive principle is: the more intense the predation, the more conspicuous certain ungulates evolve to be.

In both regions, the natural predators included large cursorial canids which scanned the groups of gazelles by day to choose the least-fit member before starting a chase of endurance.

These canids are

This preliminary scrutiny means a selective pressure for self-advertisement ('showing off'), instead of keeping a low profile.

A crucial difference was that the northern species was the only wild ruminant in most of its habitat, whereas the southern species coexisted with

The greater reliability of prey in South Africa is likely to have maintained a denser population of predators, thus boosting the risk of any particular group of the springbok being encountered by the painted hunting dog.

Imagine an evolutionary tipping point, at which the adaptive colouration of adults of the springbok lost any concealing features, and became thoroughly revealing.

The best chance for the individual springbok is not to self-efface (either in the landscape or in the group), but to announce itself as vitally as possible, disqualifying itself from being worth chasing.

In the case of the goitred gazelle, as for most other antelopes, encounters with predators remained infrequent enough that it made sense to bet-hedge, rather than committing to conspicuousness.

Red hartebeest (see https://www.picfair.com/pics/06662183-red-hartebeest-alcelaphus-buselaphus), blesbok (see https://www.123rf.com/photo_19680505_a-blesbok-antelope-damaliscus-pygargus-south-africa.html?vti=mcypwdomf20ai7hkf7-1-5) and black wildebeest (see https://rangerdiaries.com/diary/black-wildebeest-2/) also have dark/pale features obvious to predators in certain settings.

However, their overall colouration remains ambivalent (https://www.dreamstime.com/herd-springbok-steppe-south-africa-image195499685).

This may be because all are larger and more enduring in flight than the springbok, and thus less vulnerable to the painted hunting dog.

Posted on Μάιος 14, 2021 0616 ΠΜ by milewski milewski

Σχόλια

COLOURATION IN INFANTS:

goitred gazelle:

https://www.agefotostock.com/age/en/details-photo/young-goitred-gazelle/TFA-MAZ-05874/1

https://www.dreamstime.com/young-persian-goitered-gazelles-latin-name-gazella-subgutturosa-image99703125

https://www.istockphoto.com/photo/persian-gazelle-baby-gm1007108018-271761058

https://www.cms.int/cami/en/news/iucn-report-makes-recommendations-re-connecting-key-transboundary-habitat-goitered-gazelles

springbok:

https://www.inaturalist.org/observations/80401785.

The following shows how the colouration of infants, although similar to that of adults, is effectively inconspicuous. The white at the junction of flank-band and hindleg shows up in the mother by virtue of the fullness of the abdomen. By contrast, this white remains shaded in infancy, owing to the flatness of the abdomen:
https://www.inaturalist.org/observations/11064709

Αναρτήθηκε από milewski σχεδόν 2 χρόνια πριν (Αναφορά)

The springbok, over its extensive range, coexisted with up to three forms of wildebeest.

Connochaetes gnou:

https://africawild-forum.com/viewtopic.php?t=12360

https://www.youtube.com/watch?v=rr1E3nrcFsU

Connochaetes taurinus mattosi:

https://www.pond5.com/stock-footage/item/50064153-springbok-antelopes-and-blue-wildebeest-kalahari-desert-sout

https://es.123rf.com/photo_82060815_blue-wildebeest-and-springbok-standing-in-the-sand-in-the-kalagadi-transfrontier-park-south-africa.html

Connochaetes taurinus taurinus:
Coexistence with the springbok was formerly possible in Free State and Mpumalanga provinces of South Africa

Αναρτήθηκε από milewski 3 μήνες πριν (Αναφορά)
Αναρτήθηκε από milewski 3 μήνες πριν (Αναφορά)
Αναρτήθηκε από milewski 3 μήνες πριν (Αναφορά)

COMPARISON OF SAXAUL AND RIVER GANNA, as part of the habitat of goitred gazelle vs springbok:

Heptner et al. (1989, https://ia800306.us.archive.org/9/items/mammalsofsovietu11988gept/mammalsofsovietu11988gept_bw.pdf), on page 618, state:

"Goitered gazelle inhabit extremely diverse types of vegetation and are found in nearly all types of deserts and semideserts within the range. They occur in almost lifeless rocky deserts where, apart from Halogeton (https://www.inaturalist.org/observations?place_id=any&taxon_id=72160&view=species), no other higher plant life appears, as well as in rich grassy and grass-sagebrush semideserts."

"They prefer semishrub halophytic deserts and grass-halophytic semideserts. They are extremely common in shrub deserts, including sparse saxauls (https://www.inaturalist.org/taxa/349321-Haloxylon-ammodendron), but found only in the periphery of saxaul forests in summer and deep inside forests only in winter."

Please note that 'forest' exaggerates the size and density of the plants of saxaul:

https://www.inaturalist.org/observations?locale=en-US&page=2&place_id=any&taxon_id=349321

https://www.alamy.com/stock-photo-camels-grazing-in-the-gobi-tree-saxaul-forest-south-gobi-mongolia-25087909.html

https://reddplus.mn/eng/wp-content/uploads/2018/09/Saxaul-forest-in-Mongolia-and-its-ecosystem-value-ENG-2.pdf

https://www.alamy.com/stock-photo-saxaul-forest-below-khongoryn-els-sand-dunes-in-southern-gobi-desert-31109488.html

https://www.flickr.com/photos/paulbjones/8098561294

https://www.flickr.com/photos/zoienvironment/7703341122

https://www.researchgate.net/figure/Present-natural-Black-Saxaul-vegetation-cover-in-the-Ili-Delta-Lake-Balkhash-area_fig3_320167800

https://www.shutterstock.com/it/image-photo/saxaul-forest-mongolia-610690892

https://www.dreamstime.com/haloxylon-saxaul-genus-shrubs-small-trees-plant-family-amaranthaceae-haloxylon-saxaul-genus-shrubs-small-trees-plant-image215624889

The closest counterpart in the habitat of the springbok is https://www.inaturalist.org/taxa/889503-Caroxylon-aphyllum. However, the maximum size of the plants is far less than that of saxaul:

https://www.inaturalist.org/observations/8465068

https://www.inaturalist.org/observations/97529201

https://www.inaturalist.org/observations/138254731

https://www.inaturalist.org/observations/41153840

https://www.inaturalist.org/observations/35482032

https://www.inaturalist.org/observations/33590248

https://www.inaturalist.org/observations/33340836

https://www.inaturalist.org/observations/105089293

https://www.inaturalist.org/observations/8469934

https://www.inaturalist.org/observations/20184036

Αναρτήθηκε από milewski 3 μήνες πριν (Αναφορά)

@capracornelius

An aspect of the lesser conspicuousness of the goitred gazelle than of the springbok is the apparently different habits during rest. When lying down, the goitred gazelle hides, whereas the springbok does not.

Heptner et al. (1989), on page 632, state:
"The beds of goitred gazelle are usually disposed under shrubs, tall grasses, and so on, and are in the form of circular or oval pits devoid of grass and absolutely free of rubble. Along the edge of the shelter a dung heap is invariably found."

On page 62, they state:
"Beds which have been used many times are in the form of an oval pit up to 70 to 90 cm long. At the end of it there is almost invariably a heap of dung. Beds are usually disposed singly, some dozens or more metres from each other. At night goitred gazelle love to lie on smooth clay-surfaced deserts. During the day, whenever possible, they even lie under precipices. Sometimes, due to frequent usage, small niches form in such places in the cliff wall."

I infer from this that, during daylight, the goitred gazelle spends considerable periods hidden from predators.

The springbok, by contrast, lies in the open, gregariously, by daylight, wherever it happens to find itself at the time (https://www.gettyimages.com.au/detail/photo/springbok-herd-resting-royalty-free-image/WL001830 and https://es.123rf.com/photo_89449913_a-springbok-herd-resting-in-the-auob-river-valley-in-the-kgalagadi-transfrontier-park-straddling-sou.html and https://www.afripics.com/image/detail/springbok-herd-resting-in-dry-grass and https://www.alamy.com/stock-photo-springbok-antidorcas-marsupialis-male-lying-in-the-grass-with-females-59673207.html?imageid=4B08EAE1-5EE3-4C85-B8BC-F673B94630BE&p=11001&pn=1&searchId=6d4c43606c5f5d238388a54565d6b0ae&searchtype=0 and https://www.alamy.com/herd-of-resting-springbok-antidorcas-marsupialis-in-green-kalahari-desert-after-rain-season-south-africa-wildlife-image391471295.html?imageid=AB7C77F6-012C-4B82-906E-1B42768B9948&p=87725&pn=1&searchId=6d4c43606c5f5d238388a54565d6b0ae&searchtype=0 and https://www.dreamstime.com/stock-photo-herd-resting-springbok-antidorcas-marsupialis-kalahari-desert-image51826328).

Furthermore, the configuration of its flank-banding ensures that the springbok remains conspicuous even when lying down (https://www.alamy.com/springbok-antelopes-herd-resting-on-the-cold-ground-in-etosha-national-park-in-namibia-at-morning-time-antidorcas-marsupialis-image364254307.html?imageid=C01245D7-4BCB-4A83-B5BA-3EC75F6A2EE9&p=398045&pn=1&searchId=6d4c43606c5f5d238388a54565d6b0ae&searchtype=0 and https://www.dreamstime.com/herd-springbok-grooming-themselves-rainstorm-pass-herd-springbok-grooming-themselves-rainstorm-passed-image121851038).

The goitred gazelle, when lying down, is relatively inconspicous even when in plain view:
https://www.superstock.com/asset/arabian-sand-gazelle-goitered-gazelle-af-sand-gazelle-saudi-goitered/4220-20158338 and https://www.dreamstime.com/stock-photo-goitered-gazelle-gazella-subgutturosa-black-tailed-male-bush-image41400897

Αναρτήθηκε από milewski 3 μήνες πριν (Αναφορά)

The following shows the springbok in the same illumination as two species with camouflage-colouration. This illustrates the point that the white highlights on face, rump and posterior flank tend to advertise the springbok, rather than camouflaging it.

https://www.dreamstime.com/stock-photography-wildlife-waterhole-image7772582

Αναρτήθηκε από milewski 3 μήνες πριν (Αναφορά)

Heptner et al. (1989), on page 632, state in description of the goitred gazelle:
"The relatively long black tail, rising vertically with fright, and distinctly visible against the background of the white speculum, makes it easy to differentiate goitered gazelle from Mongolian gazelle, which are very similar...When resting quietly, the tail of the goitered gazelle hangs down...While running, goitered gazelle execute broad jumps, raising their head or holding it level with the trunk, and not dropping it downward like saiga do."

I do not understand what these authors mean by 'broad jumps'.

Αναρτήθηκε από milewski 3 μήνες πριν (Αναφορά)

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