Previously overlooked facial expressions in the wapiti (Cervus canadensis), with particular reference to sexual dimorphism and season

@beartracker @oviscanadensis_connerties @tandala @tonyrebelo @ludwig_muller @jeremygilmore @paradoxornithidae @capracornelius @chewitt97 @biohexx1 @jwidness @saber_animal @jamesjarrett00 @aguilita @matthewinabinett @graysquirrel @variani18 @nyoni-pete @ptexis

The wapiti (Cervus canadensis) seems to communicate socially by means of the colouration of its ears and mouth.

In related Posts, I have shown that the moose (Alces alces) shows a clear pattern at the anterior base of the ear pinna, as well as a trace of a pattern at the mouth.

See
https://www.inaturalist.org/journal/milewski/55639-auricular-semets-in-alces-and-odocoileus-but-not-other-odocoileine-deer#
https://www.inaturalist.org/journal/milewski/55694-ten-best-illustrations-of-auricular-semets-in-deer#

Here are a few reminders: http://www.laponiapictures.com/Animals/Mammals/Moose/Elk+calf,+moose+calf+among+fir+tree+branches/@toj-00528 and https://www.gettyimages.in/detail/photo/calf-of-elk-on-sumarokovos-farm-royalty-free-image/1142046649?adppopup=true and https://www.gettyimages.in/detail/photo/moose-calves-norway-royalty-free-image/1256997668?adppopup=true and https://www.alamy.com/stock-photo-moose-elk-alces-alces-close-up-of-cow-with-two-calves-resting-in-the-96452890.html.

In the wapiti, the pattern

• about the ear is even clearer than in the moose (https://www.inaturalist.org/observations/82810880), and
• about the mouth is more noticeable than in most ruminants (https://www.alamy.com/elk-red-deer-wapiti-cervus-elaphus-higashikawa-friendship-trail-canmore-alberta-canada-image437619177.html).

I have proposed that these small-scale patterns, which presumably communicate emotions, should be called semets.

For example, see:
https://www.gettyimages.in/detail/photo/portrait-of-deer-standing-in-lake-royalty-free-image/1321138547?adppopup=true and 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 and https://www.dreamstime.com/two-young-cow-elks-nose-to-nose-mountains-north-carolina-two-young-female-cow-elks-image193867144.

More particularly, the terms auricular semet and buccal semet may be apt for the ears and mouth respectively.

The auricular semet of the wapiti varies according to sex and season. It is clear in females but disappears with masculine maturity. In the winter coat the whole front-of-ear acquires a noticeable pattern, which subsumes the auricular semet even in females.

The overall result is that the auricular semet is most prominent in females and juveniles in the summer coat.

The buccal semet is fairly consistent regardless of age, sex, and season.

This semet consists of a medial dark spot on the chin (https://focusedcollection.com/359040118/stock-photo-close-head-face-cow-elk.html and https://www.alamy.com/stock-photo-a-close-up-of-two-young-bull-elk-cervus-elaphus-in-a-battle-during-90794500.html), plus a dark spot on each side near the corner of the mouth. These are offset by the pale on the rest of the front of the lower jaw (https://www.inaturalist.org/observations/4335972).

The auricular semet is more complicated to describe, because it

• is composed of two pale spots/patches, separated by the opening of the ear (https://www.alamy.com/stock-photo-female-roosevelt-elk-portrait-at-northwest-trek-wildlife-park-near-170466669.html), and
• is subsumed by a larger auricular pattern in the winter coat.

One pale spot/patch, located at the anterior base of the ear pinna, is accentuated by a dark edge. Viewed from the front, it is most striking when the ear pinna is turned partly backward (e.g. see https://gearjunkie.com/news/2-people-injured-by-elk-in-yellowstone-this-week).

The other pale spot/patch is located just to the posterior (https://www.alamy.com/stock-image-female-elk-cervus-canadensis-lying-down-and-resting-in-lime-deposits-168019993.html).

Both of these spots/patches are present in juveniles and adult females, but not adult males in autumn coat.

The following show this:
https://www.alamy.com/stock-photo-a-rear-view-of-a-large-bull-elk-cervus-elaphus-looking-away-in-a-meadow-90794793.html and https://www.alamy.com/close-up-of-a-wapiti-elk-bull-looking-away-from-the-camera-on-a-cloudy-rainy-day-in-canadian-rockies-cervus-canadensis-in-jasper-national-park-al-image424687938.html and https://www.alamy.com/stock-photo-bull-elk-cervus-canadensis-in-jasper-national-park-alberta-canada-33406575.html.

The following show that the buccal and auricular semets are present in infants and young juveniles:
https://www.gettyimages.in/detail/photo/rocky-mountain-elk-calf-royalty-free-image/568687087?adppopup=true and https://www.alamy.com/stock-photo-a-newborn-elk-calf-laying-down-on-a-graveled-area-70064369.html and https://www.inaturalist.org/observations/3750058 and https://www.denverpost.com/2017/06/25/elk-calf-broken-leg-rescued-estes-park-euthanized/.

The following shows both semets in side view:
https://www.inaturalist.org/observations/890600.

In adult males, the auricular semet fades, whereas the buccal semet remains.

Compare males (https://www.inaturalist.org/observations/88324639) with females (https://www.alamy.com/female-roosevelt-elk-portrait-image388642526.html).

The following show how noticeable the auricular semet is in summer coat in adult females, with the ear pinna turned partly backward:
https://www.inaturalist.org/observations/74525692 and https://www.inaturalist.org/observations/36411958 and https://www.inaturalist.org/observations/3839344 and https://www.inaturalist.org/observations/90071926 and https://www.inaturalist.org/observations/18970915.

When juveniles reach their first autumn, the anterior surface of the ear pinna not only grows fur, but acquires a bold pattern with pale centre and dark edges.

The following show this pattern:

https://www.masterfile.com/image/en/700-08274234/portrait-of-young-wapiti-cervus-canadensis-in-autumn-germany and https://fineartamerica.com/featured/elk-calf-mary-mikawoz.html and https://www.canstockphoto.com/elk-16304212.html. The result in the winter coat is: https://www.gettyimages.in/detail/photo/wild-elk-calf-royalty-free-image/1149459200?adppopup=true and https://www.shutterstock.com/image-photo/closeup-curious-elk-calf-64437031.

The following show the conspicuousness of both the buccal semet and the whole front-of-ear in adult females in winter:

https://www.alamy.com/stock-photo-a-portrait-image-of-a-wild-cow-elk-cervus-elaphus-against-a-blue-sky-85726508.html and https://www.gettyimages.in/detail/photo/winter-elk-royalty-free-image/519403834?adppopup=true and https://www.gettyimages.in/detail/photo/winter-elk-royalty-free-image/519403834?adppopup=true and https://www.alamy.com/stock-photo-elk-in-winter-yellowstone-national-park-usa-22561720.html.

This pattern on the ear is too large-scale to be called a semet, but does it qualify as an auricular flag?

The following shows the fading of the pattern on the front-of-ear in juvenile males in spring:

https://www.inaturalist.org/observations/88324641.

The auricular semet is lost in adult males, even in summer (https://www.inaturalist.org/observations/85155079 and https://www.inaturalist.org/observations/84391293).

This loss is understandable, because the antlers

• become dominant for social communication in masculine maturity, and
• have their own accentuation by virtue of the paleness of the points (https://pixels.com/featured/elk-horns-wildlife-fine-art.html).

An obvious question arises once the sexual difference has been noticed, as follows:

In females, is it that

• the ears compensate for the lack of antlers for the purpose of communicating annoyance and social dominance, or
• the main function of the auricular semet is for mutual monitoring of auditory attention - according to the routine swivelling of the ears - as part of gregarious vigilance?

If the latter is true, is the loss of this facility in males in line with the typical riskiness of masculine bravado?

Do readers see that there are intriguing differences in this language between the sexes, which naturalists have an opportunity to figure out? (See https://www.inaturalist.org/journal/milewski/69281-intriguing-new-sexual-dimorphism-in-the-wapiti#.)

To be continued in https://www.inaturalist.org/journal/milewski/55639-auricular-semets-in-alces-and-odocoileus-but-not-other-odocoileine-deer#...

Posted on August 22, 2021 10:37 AM by milewski