Illustrations of the walking and stotting gaits of the pronghorn (Antilocapra americana)

@beartracker @maxallen @aguilita @jwidness @matthewinabinett @davidbygott @ptexis @taogirl @variani18

INTRODUCTION

The pronghorn (Antilocapra americana) is renowned for its extreme speed and endurance when galloping - a topic which I do not address in this Post.

Instead, my aim is to illustrate the following, lesser-known gaits of the pronghorn, viz.

• various walking gaits, and
• various display gaits, the function of which is partly to signal individual fitness to predators and/or conspecifics.

The gaits of the pronghorn were well-documented more than 40 years ago (Bullock 1982, https://d1wqtxts1xzle7.cloudfront.net/38898576/Franklin_Vicuna_1974.pdf?1443280555=&response-content-disposition=inline%3B+filename%3DThe_Social_Behavior_of_the_Vicuna_p_477.pdf&Expires=1712873946&Signature=SECkGoREl0a4cUhkekReWb~lmpS6pcXk3a8mKqpPS1NBzaognfNWVSikWAgOp8og4Zg5hKKo7IwBdCpRhQJoFctQfmEmTybFmoOLzO4mw5I6veY5WEbKvheRW6Fs1KwCuTXl-7JONfeN1~hknoodkwwpFlnCA4Jx7k6Z6UzoL~T3CSTtUAgdBOhfXJBPHUTLzjELAzBrYbmWIsfTh3LCiJAjQyeqerYW32CUzD7OQs4nUk-yyMG028rFb-yvfhlYljCstpqVvzsPMc1ppUe1xlbg4xrtVh59t1-H7XDKRYeu-CXvagQt-pDu7aMuBrsYKaQXR0qcAwCElwV6b4jVbg__&Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA#page=272 and https://cdnsciencepub.com/doi/abs/10.1139/z82-243?journalCode=cjz and https://www.researchgate.net/publication/237992215_An_analysis_of_locomotor_body_movements_in_pronghorn_antelope and https://cdnsciencepub.com/doi/abs/10.1139/z82-243 and https://www.jstor.org/stable/3830497).

However, it is only now that there are enough photos of this species on the Web to illustrate certain gaits clearly. The terms I use do not necessarily correspond to those of Bullock (1982).

RESULTS

Cross-walking:

https://medium.com/usfws/rare-sonoran-pronghorn-are-rebounding-5de9c5343ded

https://www.inaturalist.org/observations/151154169

https://www.inaturalist.org/observations/111103776

https://www.inaturalist.org/observations/192148380

https://www.inaturalist.org/observations/7877948

https://www.inaturalist.org/observations/45872075

https://www.inaturalist.org/observations/45933776

https://www.inaturalist.org/observations/22592549

https://www.inaturalist.org/observations/198888097

https://www.inaturalist.org/observations/67474435

https://www.inaturalist.org/observations/60448113

https://www.inaturalist.org/observations/49918376

https://www.inaturalist.org/observations/14608967

https://www.inaturalist.org/observations/206380030

https://www.inaturalist.org/observations/188952650

https://www.inaturalist.org/observations/136027864

https://www.inaturalist.org/observations/120592993

https://www.inaturalist.org/observations/117610955

https://www.inaturalist.org/observations/112181226

https://www.inaturalist.org/observations/105114626

https://www.inaturalist.org/observations/34874373

https://www.inaturalist.org/observations/27069190

https://www.inaturalist.org/observations/646613

https://www.inaturalist.org/observations/172730233

https://www.inaturalist.org/observations/160784537

https://www.inaturalist.org/observations/86366821

https://www.inaturalist.org/observations/69182943

https://www.inaturalist.org/observations/126642775

https://www.inaturalist.org/observations/168931232

https://www.inaturalist.org/observations/149564088

https://www.inaturalist.org/observations/104441773

https://www.inaturalist.org/observations/72881424

https://www.inaturalist.org/observations/28156962

https://www.inaturalist.org/observations/194604847

https://www.inaturalist.org/observations/189136437

https://www.inaturalist.org/observations/188672871

https://www.inaturalist.org/observations/169802309

https://www.inaturalist.org/observations/169102077

https://www.inaturalist.org/observations/164225148

https://www.inaturalist.org/observations/141591681

https://www.inaturalist.org/observations/128406785

https://www.inaturalist.org/observations/58704010

https://www.inaturalist.org/observations/25524800

https://www.inaturalist.org/observations/369882

https://www.inaturalist.org/observations/198029380

https://www.inaturalist.org/observations/83973812

https://www.inaturalist.org/observations/38435151

https://www.inaturalist.org/observations/19730539

https://www.inaturalist.org/observations/81736547

https://www.inaturalist.org/observations/18340076

https://www.inaturalist.org/observations/13011401

https://www.inaturalist.org/observations/10091257

https://www.inaturalist.org/observations/180569759

https://www.inaturalist.org/observations/162597053

https://www.inaturalist.org/observations/112784916

https://www.inaturalist.org/observations/206481220

https://www.inaturalist.org/observations/167297136

https://www.inaturalist.org/observations/144115273

https://www.inaturalist.org/observations/124978685

https://www.inaturalist.org/observations/202996237

Semi cross-walking:

https://www.storyblocks.com/video/stock/pronghorn-antelope-walking-in-the-plains-hag1g3ixwj2v2c9nu

https://stock.adobe.com/video/pronghorn-antelope-walking-in-the-plains/191515413?as_campaign=ftmigration2&as_channel=dpcft&as_campclass=brand&as_source=ft_web&as_camptype=acquisition&as_audience=users&as_content=closure_asset-detail-page

https://www.storyblocks.com/video/stock/pronghorn-antelope-tracked-while-walking-in-grass-ki1bmav

https://www.inaturalist.org/observations/169977981

https://www.inaturalist.org/observations/81226031

https://www.inaturalist.org/observations/165599558

https://www.inaturalist.org/observations/77144531

https://www.inaturalist.org/observations/108666122

https://www.inaturalist.org/observations/4682916

https://www.inaturalist.org/observations/180187343

https://www.inaturalist.org/observations/141759202

https://www.inaturalist.org/observations/116033559

https://www.inaturalist.org/observations/95166793

https://www.inaturalist.org/observations/190532708

https://www.inaturalist.org/observations/187425583

https://www.inaturalist.org/observations/187403044

https://www.inaturalist.org/observations/164915852

https://www.inaturalist.org/observations/161660531

https://www.inaturalist.org/observations/120618226

https://www.inaturalist.org/observations/112788711

https://www.inaturalist.org/observations/45924357

https://www.inaturalist.org/observations/37510543

https://www.inaturalist.org/observations/7975933

https://www.inaturalist.org/observations/173803819

https://www.inaturalist.org/observations/192932980

https://www.inaturalist.org/observations/24766943

https://www.inaturalist.org/observations/2313666

https://www.inaturalist.org/observations/202605521

https://www.inaturalist.org/observations/105126822

https://www.inaturalist.org/observations/16640889

https://www.inaturalist.org/observations/181843893 and https://www.inaturalist.org/observations/179269836

https://www.inaturalist.org/observations/181284223

https://www.inaturalist.org/observations/176878956

https://www.inaturalist.org/observations/172456278

https://www.inaturalist.org/observations/138443166

https://www.inaturalist.org/observations/135297540

https://www.inaturalist.org/observations/130235159

https://www.inaturalist.org/observations/123661093

https://www.inaturalist.org/observations/92061482

https://www.inaturalist.org/observations/90601957

https://www.inaturalist.org/observations/27175238

https://www.inaturalist.org/observations/25857516

https://www.inaturalist.org/observations/19058413

https://www.inaturalist.org/observations/12998710

https://www.inaturalist.org/observations/199628

https://www.inaturalist.org/observations/159245812

https://www.inaturalist.org/observations/192495811

https://www.inaturalist.org/observations/173367219

https://www.inaturalist.org/observations/124848728

https://www.inaturalist.org/observations/124652556

https://www.inaturalist.org/observations/105552317

https://www.inaturalist.org/observations/90042028

https://www.inaturalist.org/observations/77808716

https://www.inaturalist.org/observations/71174311

https://www.inaturalist.org/observations/66697932

https://www.inaturalist.org/observations/19299335

https://www.inaturalist.org/observations/1434006

https://www.inaturalist.org/observations/192755246

https://www.inaturalist.org/observations/184207314

https://www.inaturalist.org/observations/181446232

https://www.inaturalist.org/observations/170446653

https://www.inaturalist.org/observations/168856780

https://www.inaturalist.org/observations/153092774

https://www.inaturalist.org/observations/123618854

https://www.inaturalist.org/observations/116494036

https://www.inaturalist.org/observations/71882182

https://www.inaturalist.org/observations/62759588

https://www.inaturalist.org/observations/57729297

https://www.inaturalist.org/observations/39740119

https://www.inaturalist.org/observations/8697208

https://www.inaturalist.org/observations/178173951

https://www.inaturalist.org/observations/165313189

https://www.inaturalist.org/observations/40796530

https://www.inaturalist.org/observations/5173255

https://www.inaturalist.org/observations/200516676

https://www.inaturalist.org/observations/131997891

https://www.inaturalist.org/observations/128984894

https://www.inaturalist.org/observations/128984893

https://www.inaturalist.org/observations/108361908

https://www.inaturalist.org/observations/60921261

https://www.inaturalist.org/observations/28039844

https://www.inaturalist.org/observations/6186244

https://www.inaturalist.org/observations/171266598

https://www.inaturalist.org/observations/125877305

https://www.inaturalist.org/observations/116925430

https://www.inaturalist.org/observations/104078696

https://www.inaturalist.org/observations/62604018

https://www.inaturalist.org/observations/38034079

Ambling:

https://www.shutterstock.com/da/video/clip-1093543127-pronghorn-antelope-walking-through-utah-desert-during

https://blog.gritrsports.com/big-game-profile-pronghorn/

https://www.oceanlight.com/spotlight.php?img=19627

https://www.inaturalist.org/observations/74202062

https://www.inaturalist.org/observations/172746714

https://www.inaturalist.org/observations/41200343

https://www.inaturalist.org/observations/60531788

https://www.inaturalist.org/observations/5119706

https://www.inaturalist.org/observations/38203216

https://www.inaturalist.org/observations/89398530

https://www.inaturalist.org/observations/26399635

https://www.inaturalist.org/observations/161080559

https://www.inaturalist.org/observations/137670731

https://www.inaturalist.org/observations/197367318

https://www.inaturalist.org/observations/137336427

https://www.inaturalist.org/observations/193225312

https://www.inaturalist.org/observations/153326755

https://www.inaturalist.org/observations/14970879

https://www.inaturalist.org/observations/160981894

https://www.inaturalist.org/observations/143827822

https://www.inaturalist.org/observations/165313190

https://www.inaturalist.org/observations/143377354

https://www.alamy.com/video/pronghorn-walking-in-a-field-582837040.html

https://www.inaturalist.org/observations/75666276

Proud-trotting:

https://www.inaturalist.org/observations/162332610

https://www.inaturalist.org/observations/6506049

https://www.inaturalist.org/observations/119916340

https://www.inaturalist.org/observations/28842659

https://www.inaturalist.org/observations/10151399

https://www.inaturalist.org/observations/196884072

https://www.inaturalist.org/observations/153327177

https://www.inaturalist.org/observations/142944555

https://www.inaturalist.org/observations/65214769

https://www.youtube.com/watch?v=58bODe6e7gA

Stotting:

https://pngtree.com/freebackground/pronghorned-antelope-running-through-field-hunting-color-fauna-photo_3819221.html

Scroll in https://content.govdelivery.com/accounts/USDOI/bulletins/3478106

Scroll in https://www.azcentral.com/picture-gallery/news/local/glendale/2015/09/24/11-things-you-might-not-know-about-luke-air-force-base/72030292/

https://blissphotographics.com/pronking-pronghorn-levitating/

https://blissphotographics.com/pronghorn-levitation-stotting-or-pronking/

https://www.pinterest.com.au/pin/graceful-pronghorn-in-midair--320529698481685013/

https://www.inaturalist.org/observations/99162488

https://www.inaturalist.org/observations/26690567

https://www.inaturalist.org/observations/153327177

https://www.inaturalist.org/observations/20058575

https://www.inaturalist.org/observations/81342377

https://www.inaturalist.org/observations/18212065

https://www.inaturalist.org/observations/5028581

https://www.alamy.com/stock-photo-pronghorn-antelope-antilocapra-americana-fawn-running-in-grassland-26797480.html

DISCUSSION

The pronghorn conforms to a category of ungulates that I have called 'plains game'.

This is because it combines the following features/traits:

• exposed habitat, lacking cover,
• gregariousness,
• cursoriality and migration (https://www.youtube.com/watch?app=desktop&v=ig2VR6aAu4M),
• lateral placement of the eyes (https://www.inaturalist.org/observations/86028387 and https://www.inaturalist.org/observations/20720325 and https://www.youtube.com/watch?v=j5QQ85aXipc and https://www.inaturalist.org/observations/123766827 and https://www.inaturalist.org/observations/79483159),
• conspicuous colouration, even at distance (https://www.inaturalist.org/observations/67782104 and https://www.inaturalist.org/observations/70291649 and https://www.inaturalist.org/observations/116295944 and https://www.inaturalist.org/observations/9807652 and https://www.inaturalist.org/observations/197435261 and https://www.inaturalist.org/observations/33663443 and https://www.inaturalist.org/observations/2678702 and https://www.inaturalist.org/observations/53522820),
• minor sexual dimorphism (https://www.inaturalist.org/observations/144092409 and https://www.inaturalist.org/observations/128676306 and https://www.inaturalist.org/observations/187659485 and https://www.inaturalist.org/observations/138672584 and https://www.inaturalist.org/observations/146685807),
• reluctance to jump over fences (https://tpwd.texas.gov/publications/pwdpubs/media/pwd_lf_w7000_1787.pdf and https://www.facebook.com/watch/?v=854823252123488 and https://www.greatfallstribune.com/videos/news/2017/05/05/watch-pronghorn-crawling-underneath-fences/101298706/ and https://www.youtube.com/watch?v=hnVHZBin5x4 and https://www.youtube.com/watch?v=XyvfiNDtiAI and https://www.inaturalist.org/observations/115502513 and https://www.youtube.com/watch?v=VyVwSi4A6ps and https://www.youtube.com/watch?v=aJMTc8wqDl0), and
• seasonal reproduction.

Species of 'plains game' in the family Bovidae, in Africa and Eurasia, typically amble. I refer to all Alcelaphini and Hippotagini, and certain Antilopini, Reduncini, and possibly Caprini.

Based on its evolutionary convergences with 'plains game', we would expect the pronghorn to amble.

However, Bullock (1982) - despite the thoroughness of his study - did not find the pronghorn to amble.

So, is it true that the pronghorn is anomalous relative to bovid 'plains game', in lacking an ambling gait?

My study, as illustrated in this Post, offers a correction to Bullock (1982). In fact, the pronghorn does sometimes amble.

The pronghorn is partly aligned with Cervidae, a family in which ambling is absent in even those species

• most resembling 'plains game', e.g. Cervus canadensis, and
• with the most lateral placement of the eyes, e.g. Dama dama.

The following (https://www.inaturalist.org/observations/133255783 and https://www.youtube.com/watch?v=V8-1p8WhAYo and https://www.youtube.com/watch?v=r72AnyDaxS0) show the cross-walk typical of Cervidae.

On this basis, it would seem that the pronghorn incongruously combines cross-walking with extreme speed and endurance of galloping.

The diagnostic pattern of 'diagonal' walking gaits - including the cross-walk of the pronghorn - is that the hind foot lifts only once the contralateral foot lands, and the hind foot lands approximately in the track of the ipsilateral fore foot (https://www.inaturalist.org/observations/40017869 and https://www.inaturalist.org/observations/65114417 and https://www.inaturalist.org/observations/204861686 and https://www.inaturalist.org/observations/167405274 and https://www.inaturalist.org/observations/18491683).

Bullock (1982) documented that the pronghorn varies this in two ways, viz.

• the hind foot lifts only once the contralateral fore foot lands (= what I term 'nearly ambling'), and/or
• the hind foot lands slightly anterior to the track of the ipsilateral fore foot (possibly shown in https://www.inaturalist.org/observations/775048).

However, Bullock (1982) failed to document the full versatility of walking gaits in the pronghorn.

The following (https://www.inaturalist.org/observations/126912485) shows this versatility. The juvenile individual on the left is cross-walking, while that on the right is ambling.

In the case of 'display gaits', there is also something new to be investigated about the pronghorn. This is the possibility of two 'display gaits' additional to stotting (in the narrow sense).

These are

• exaggerated cross-walking (resembling that in cervids e.g. Odocoileus, https://www.sierraclub.org/sierra/assisted-migration-helps-animals-adapt-climate-change), and
• exaggerated trotting (= proud-trotting, resembling that in bovids e.g. Alcelaphus).

However, I have found few unambivalent illustrations of stotting/display gaits in the pronghorn, in either the strict or the loose sense. According to Bullock (1982), stotting is mainly an intraspecific (as opposed to anti-predator) display in the pronghorn, and observed mainly in the breeding season. However, this remains poorly documented photographically.

It is remarkable that infants seem not to stot during play behaviour (https://www.youtube.com/watch?v=ZwE_IFvABKw and https://www.youtube.com/watch?v=NQdzJm0A5co).

The pronghorn is extreme, among ungulates, in advertising itself by means of piloerection of the white bleeze on the hindquarters (https://www.inaturalist.org/observations/17052354 and https://www.inaturalist.org/observations/144032230 and https://www.inaturalist.org/observations/124828985).

However, any correlation between gait and the piloerection of this acetabulo-ischiopygal bleeze - which often occurs when the figure is stationary - is weak.

MAIN QUESTIONS RAISED

This investigation has raised three main questions about the gaits of the pronghorn, as follows. In this species,

• under which circumstances does ambling occur?
• why - in adaptive terms - has the pronghorn retained a cross-walking gait, despite otherwise conforming to 'plains game'? and
• why does stotting occur mainly for intraspecific display and in adults, rather than - as in most other ruminants - mainly for anti-predator display and in infants and juveniles?

Also see

• https://www.inaturalist.org/journal/milewski/52136-the-mane-as-a-little-known-aspect-of-the-erectile-bleeze-of-the-pronghorn-antilocapra-americana#
• https://www.inaturalist.org/posts/52201-the-peculiar-showiness-of-the-subauricular-gland-of-the-pronghorn-antilocapra-americana#
• https://www.inaturalist.org/posts/52221-why-the-pronghorn-antilocapra-americana-has-a-striped-neck#
• https://www.inaturalist.org/journal/milewski/52296-interpreting-the-buccal-semet-of-the-pronghorn-antilocapra-americana#

Posted on April 11, 2024 09:39 PM by milewski