A new explanation for the hypercursoriality of the pronghorn (Antilocapra americana): selenium as a crucial micronutrient

The pronghorn (Antilocapridae: Antilocapra americana) is renowned for its extreme speed and endurance when running (https://www.youtube.com/watch?v=jR18k9c3MsE).

It is widely accepted that no animal on Earth exceeds the pronghorn in this combination.

Skeptical readers may perhaps suspect that the performance of the pronghorn my perhaps have been exaggerated.

However, the claims of speed and endurance are consistent with several other exceptional/extreme features, viz.

extremely large heart and lungs,
a consistent habit of opening the mouth while galloping,
long-range visual vigilance,
long-distance signalling by means of 'semaphoric' pale patches on the pelage, and
a lack - relative to other forms of 'plains game' - of displays of individual fitness to scanning predators.

All of the above add up to a syndrome of apparent 'hypercursoriality' in the pronghorn.

This syndrome seems incongruous, because the predatory regime in which the pronghorn lives is less, not more, intense than that pertaining to 'plains game' in Africa and Eurasia.

https://www.perplexity.ai/search/Compare-the-maximum-RVcPX3W1Q5GD5EbGMHJ5Vw

The long-range visual vigilance of the pronghorn is indicated partly by fully lateral placement of the eyes on the head, permitting the pronghorn to scan the horizon behind it as well as in front and to the sides.

However, this in itself hardly differs from 'plains game' in Africa and Eurasia.

What distinguishes the pronghorn are

extremely large eyeballs, both absolutely for a mammal and relative to body size, and
bony orbits that protrude from the skull laterally, to a degree possibly exceeding that in any other ungulate.

The long-distance signalling of the pronghorn is indicated partly by a conspicuously pale patch on the hindquarters (https://www.inaturalist.org/observations/211220855 and https://www.flickr.com/photos/189038430@N06/53350736417/in/faves-58287925@N05/ and https://pngtree.com/freebackground/pronghorn-antelope-buck-antlers-hunting-pronghorn-nature-photo_4107882.html).

However, various other forms of 'plains game' have comparable features of colouration.

What is extreme in the case of the pronghorn is

extreme piloerection of the acetabulo-ischiopygal bleeze, which expands it into a disc-like feature with accentuated borders (https://www.flickr.com/photos/189038430@N06/53349701594/in/faves-58287925@N05/ and https://www.reddit.com/r/AnimalPorn/comments/b7nc5f/pronghorn_doe_in_alert_posture_oc/#lightbox and https://www.facebook.com/watch/?v=595650625349272 and https://www.agefotostock.com/age/en/details-photo/pronghorn-gabelbock-gabelantilope-antilocapra-americana-in-winter-attentive-animal-scared-erecting-its-white-hairs-on-its-rump-yellowstone-area-usa/VX1-3111450 and https://pngtree.com/freebackground/pronghorn-antelope-buck-running-through-field-digital-fauna-animal-photo_3822003.html), and
peculiarly luminous whiteness when thus piloerected, appearing like a flashing beacon, even (to the human eye) at distances of more than one kilometer (https://pngtree.com/freebackground/pronghorn-antelope-in-saskatchewan-field-wild-animal-rural-horizontal-photo_3839252.html and https://pngtree.com/freebackground/pronghorn-antelope-male-sprinting-across-saskatchewans-grassy-expanse-photo_3839357.html).

The limited incidence of displays of individual fitness in the pronghorn is not categorically different from various 'plains game' in Africa. For example, Damaliscus spp. tend not to stot, despite being extremely cursorial among Bovidae.

However, what is odd in the case of the pronghorn is that

stotting, to the extent that it occurs among adults, is displayed mainly sociosexually, rather than to potential predators,
'style-trotting' is rather poorly-developed, and
neither stotting nor proud-trotting occur in juveniles, even while playing.

This raises the question:

Selenium:

https://www.horizons-mag.ch/2017/04/03/the-world-map-of-a-trace-element/

https://www.researchgate.net/figure/Selenium-distribution-and-availability-in-regions-of-the-continental-United-Sates-Panel_fig3_228832815

https://extension.uga.edu/publications/detail.html?number=B1390&title=selenium-in-georgia-soils-and-forages-importance-in-the-livestock-industry

https://drkhorsesense.wordpress.com/2021/03/11/lose-your-fear-of-selenium/

https://poisonousplants.ansci.cornell.edu/toxicagents/selenium_map.html

https://pubs.usgs.gov/publication/70006713

https://meridian.allenpress.com/jwd/article/32/1/9/121989/TOXICOLOGIC-EVALUATION-OF-A-HIGH-SELENIUM-HAY-DIET

https://customequinenutrition.com/blogs/nutrients/selenium-101

https://www.researchgate.net/figure/Indicators-of-environmental-selenium-status-for-the-USA-Selenium-rich-environments_fig2_40455792

https://bioone.org/journals/journal-of-zoo-and-wildlife-medicine/volume-32/issue-3/1042-7260_2001_032_0373_PCDIHR_2.0.CO_2/PRESUMPTIVE-COPPER-DEFICIENCY-IN-HAND-REARED-CAPTIVE-PRONGHORN-ANTILOCAPRA-AMERICANA/10.1638/1042-7260(2001)032[0373:PCDIHR]2.0.CO;2.short