Bipedal versatility in ruminants, part 1

Also see https://www.inaturalist.org/journal/milewski/67632-locomotory-and-postural-peculiarities-of-the-impala-part-2#

Ruminants (deer, bovids, musk deer, giraffes, pronghorns and chevrotains) stand and run on all fours. However, some species are able to free-stand bipedally to forage or to quarrel, and it is here that intriguing patterns await discovery by naturalists.

I refer to standing upright with the back vertical but without propping the forelegs on branches or other supports.

What is obvious from perusal of photos on the Web is that ruminants differ categorically in their bipedal versatility. I have seen thousands of photos of, for example, the impala (Aepyceros melampus), without finding any evidence of free-standing bipedally. By contrast it takes only a few minutes to find such evidence in the case of deer (Cervidae) resembling the impala in body size and proportions.

In this, part 1, I show that many species of deer are bipedally versatile. In part 2, we will see that other families of ruminants lack this versatility except for a few genera of bovids. In part 3, I will offer some explanations of these findings.

The following show that a dozen or more species of deer in at least eight genera, including both sexes, are able to free-stand bipedally. The photographic evidence is clear for both foraging and social antagonism. Free-standing bipedally while quarreling is seen not only in females but also in males while the growing antlers (still in velvet) risk permanent damage from any attempts to butt each other.

In quarreling while free-standing bipedally, a typical action for deer is to flail the fore hooves downwards threateningly. The mouth is held horizontal and the ears are turned back. This suggests that the muzzle-ring functions as a buccal semet in this context; and in the relatively few species possessing suitable patterns on the ears there is also evidence of auricular semets.

Alces alces

This species sometimes forages by standing upright (https://books.google.com.au/books?id=DHciAQAAIAAJ&pg=RA12-PA4&lpg=RA12-PA4&dq=Do+moose+ever+stand+on+their+hind+legs+to+feed?&source=bl&ots=smMugx5yTE&sig=ACfU3U3OmyZ6QxYH5KLhvA5tuPcJPaLyDA&hl=en&sa=X&ved=2ahUKEwi27s6J-ePyAhWdyzgGHaKeD4IQ6AF6BAg7EAM#v=onepage&q=Do%20moose%20ever%20stand%20on%20their%20hind%20legs%20to%20feed%3F&f=false), but I do not know whether this includes free-standing bipedally

https://www.gettyimages.com.au/detail/video/shot-of-two-cow-moose-standing-on-their-hind-legs-and-stock-footage/611032370

https://www.gettyimages.com.au/detail/video/cow-moose-standing-up-on-their-hind-legs-and-fighting-in-stock-footage/460383460

https://www.canadiannaturephotographer.com/Joe_Desjardins.html

Rangifer tarandus

I suspect that this species forages for lichens in trees during winter by free-standing bipedally, but I have yet to find photos

https://jamitarris.photoshelter.com/image/I00005tp15iuzJ9U

Odocoileus virginianus

https://www.alamy.com/two-white-tailed-does-fighting-image65174184.html

https://www.alamy.com/stock-photo-white-tailed-deer-odocoileus-virginianus-doe-standing-on-hind-legs-125308775.html

https://www.alamy.com/stock-photo-white-tailed-deer-odocoileus-virginianus-stag-on-hind-legs-eating-21416640.html

https://www.pbase.com/merriwolf/image/88480123&exif=N

https://baseoutdoor.com/outdoors-lifestyle/do-deer-eat-fruit/

https://www.alamy.com/stock-photo-key-deer-odocoileus-virginianus-clavium-female-standing-on-hind-legs-125537812.html

https://twitter.com/iowadnr/status/1357523345764454400

https://www.dreamstime.com/white-tailed-deer-stands-its-hind-legs-to-eat-white-tailed-deer-winter-standing-its-hind-legs-to-feed-leaves-image126375621

https://www.alamy.com/stock-photo-white-tailed-deer-odocoileus-virginianus-stag-standing-on-its-hind-21413686.html

https://fineartamerica.com/featured/deer-on-hind-legs-joanne-rungaitis.html?product=greeting-card

https://deer.wildlifeillinois.org/deer-ecology/deer-signs/

https://www.alamy.com/stock-photo-white-tailed-deer-odocoileus-virginianus-adults-fighting-sinton-corpus-26213864.html

Odocoileus hemionus

https://themeditativegardener.blogspot.com/2020/09/apples-tempting-deer.html

https://tonybynum.photoshelter.com/image/I0000lOsyLfVxp0c

Dama dama

https://www.alamy.com/stock-photo-fallow-deer-doe-eating-apples-off-tree-in-garden-worcestershire-england-11560798.html

https://www.123rf.com/photo_87331943_proud-male-fallow-deer-stag-dama-dama-with-big-antlers-stand-up-straight-on-hind-legs-to-reach-for-l.html

https://www.dreamstime.com/proud-male-fallow-deer-stag-dama-dama-big-antlers-stand-up-straight-hind-legs-to-reach-leaves-dark-green-forest-image104251866

https://www.dreamstime.com/male-fallow-deer-dama-stand-up-straight-hind-legs-proud-stag-big-antlers-to-reach-leaves-dark-green-forest-image100979759

https://www.123rf.com/photo_87331940_proud-male-fallow-deer-stag-dama-dama-with-big-antlers-stand-up-straight-on-hind-legs-to-reach-for-l.html

https://www.dreamstime.com/fallow-deer-rears-up-its-hind-legs-to-reach-fruit-hanging-tree-branch-fallow-deer-rears-up-its-hind-legs-image118260844

https://depositphotos.com/127523954/stock-photo-fallow-deer-during-rutting-season.html

https://www.alamy.com/a-fallow-deer-rears-up-on-its-hind-legs-to-reach-the-fruit-hanging-on-the-tree-branch-image218850894.html

Cervus canadensis

https://www.mindenpictures.com/stock-photo-rocky-mountain-elk-cervus-canadensis-nelsoni-female-standing-on-hind-naturephotography-image00535438.html

https://www.123rf.com/photo_79810435_two-male-elk-fighting-each-other-on-hind-legs-in-snowy-meadow-in-colorado-.html

https://www.alamy.com/two-elk-standing-on-their-hind-legs-sparring-with-each-other-with-their-hoofs-in-yellowstone-national-park-wyoming-the-united-states-image215639224.html

Cervus elaphus

https://www.alamy.com/red-deer-cervus-elaphus-two-conflicting-female-competitors-standing-upright-netherlands-gelderland-hoge-veluwe-national-park-hoenderloo-image255221631.html

https://www.alamy.com/stock-photo-red-deer-cervus-elaphus-hind-standing-on-rear-legs-to-browse-on-oak-104402838.html

https://www.alamy.com/red-deer-cervus-elaphus-two-hinds-standing-upright-vis-a-vis-netherlands-hoge-veluwe-national-park-image255400292.html

https://www.alamy.com/female-red-deer-cervus-elaphus-hind-stood-on-back-legs-eating-leaves-image62247947.html

https://www.the-sun.com/news/901340/stags-fight-herd-dominance-pictures/

https://www.alamy.com/stock-photo-red-deer-stags-fight-with-their-front-legs-when-the-new-antlers-grow-71435659.html

https://www.dreamstime.com/stock-photo-red-deer-standing-hind-legs-eating-leaves-image45485247

https://www.dreamstime.com/royalty-free-stock-image-fighting-red-deer-stags-image15987976

https://www.dreamstime.com/two-red-deer-hinds-fighting-meadow-summertime-nature-cervus-elaphus-pair-od-standing-duel-grassland-sunlight-females-image208144629

https://www.dreamstime.com/stock-image-profile-fallow-deer-eating-tree-edge-river-rearing-up-hind-legs-to-eat-low-hanging-leaves-branches-image32681821

https://www.alamy.com/stock-photo-female-red-deer-standing-on-her-hind-legs-to-reach-and-eat-oak-leaves-123409123.html

Cervus nippon

https://www.dreamstime.com/stock-photography-deer-fighting-image22432872

https://www.flickr.com/photos/183548200@N02/50554859006

Rusa unicolor

https://www.dreamstime.com/stock-image-deer-image3401171

https://www.jungledragon.com/image/77322/reach_for_the_top_-_sambar_deer_on_two_legs.html

https://www.gettyimages.com.au/detail/photo/sambar-deer-standing-on-its-hind-legs-to-reach-for-royalty-free-image/1024483926

https://www.researchgate.net/figure/Mature-female-Rusa-unicolor-browsing-from-her-hind-legs-a-common-position-of-the_fig4_273099153

https://www.alamy.com/stock-photo-sambar-deer-cervus-unicolour-playing-in-the-water-with-one-standing-11561588.html

Elaphurus davidianus

https://www.naturepl.com/stock-photo/pere-david-39s-deer-(elaphurus-davidianus)-two-stags-boxing-amongst-herd-of/search/detail-0_01629333.html

Axis axis

https://www.alamy.com/india-kanha-np-chital-deer-spotted-deer-male-browsing-from-tree-image7350629.html

https://www.kellogggarden.com/wp-content/uploads/2020/04/Deer-Eating.jpg

https://www.alamy.com/chital-standing-on-his-hind-legs-to-get-the-leaves-image2114794.html

https://www.istockphoto.com/photo/deer-with-beautiful-horns-standing-on-hind-legs-in-jungle-in-the-wild-india-national-gm696640282-129310817

https://www.readphotos.com/products/465/deer-standing-two-legs-dilhan-wimalka

Muntiacus reevesi

https://www.alamy.com/stock-image-baby-muntjac-also-known-as-barking-deer-muntiacus-reevesi-eating-red-164105622.html

to be continued...

Publicado el 3 de septiembre de 2021 09:46 por milewski