Does the colouration of the giant panda hint of anti-predator defence by means of mutilating premolars? part 2

(writing in progress)

...continued from https://www.inaturalist.org/journal/milewski/66693-does-the-colouration-of-the-giant-panda-hint-of-anti-predator-defence-by-means-of-mutilating-premolars-part-1#

Now let us examine the colouration around the eyes, in the giant panda, other bears, and the red panda (Ailurus fulgens, https://www.inaturalist.org/taxa/41653-Ailurus-fulgens) - which belongs to a different family but has a similar diet of bamboo and similar habitat in the same region of Asia.

The ocular patches of the giant panda are starker than those of any other bear. However, the blackness of the fur around these eyes is only the starkest expression of a pattern shared in subtle form with other bears – particularly the partly bamboo-eating spectacled bear (Tremarctos ornatus, https://www.inaturalist.org/taxa/41657-Tremarctos-ornatus) of the Andes.

What is the function of the ocular exaggeration seen in the giant panda?

Dark ocular patches, bands and stripes are more common in carnivorous mammals than in herbivorous mammals. Depending on the details, they can hypothetically aid either crypsis or conspicuousness. Few non-noxious species of the carnivore order combine an eye-mask with cryptic colouration. In the case of the suricate (Suricata suricatta, https://www.inaturalist.org/taxa/41943-Suricata-suricatta), which overall has cryptic rather than conspicuous colouration and is associated with salinas, the ocular patches possibly function to reduce glare.

And where they aid conspicuousness, this is usually indirectly by drawing attention away from the eyes towards a whole-body pattern of contrasting dark and pale, as typified by skunks (Mephitidae, https://www.inaturalist.org/observations?taxon_id=41871).

In Mustelidae, various species with warning colouration seem to mask their eyes in various designs. Perhaps it serves the untrustworthy image of bad-smelling members of the Carnivora to hide their eyes even as they advertise their noxiousness by means of dark-and-pale flags. This must seem sinister or at least confusing to a large antagonist.

Based on my interpretation of eye-masks in Carnivora, it might be consistent to suggest that pandas hide their eyes in combination with otherwise conspicuous colouration as a form of warning.

However, I suggest that the giant panda is one species – and possibly the only one in its order – that uses ocular patches in a different way, Instead of hiding its eyes, it emphasises them in a false stare. This is a subtle difference from the mustelid pattern but would also be configured to confuse enemy species in confrontation.

As observed by humans, the dark ocular patches of the giant panda seem not to mask but rather to accentuate the eyes as 'larger-than-life'. The species inadvertently panders to our biases by being rotund and furry, with a broad face and ocular patches that face forward as in humans and simulate the proportionately large eyes of youth. This anthropomorphic impression is of course psychological, because the real eyes of the giant panda, like those of all bears, are disappointingly small and 'piggy'.

However, as observed by the relevant predators:
In light too dim to show the real eyes but adequate to show the white face, the dark ocular patches of the giant panda would exaggerate rather than hide the eyes.

A large felid would probably not see the eyeballs of the giant panda, which are inconspicuous even in bright light because the iris is dark and the eye-whites (scleras) are hardly exposed. But the staring ocular patches, seeming to be the eyes of a larger-than-life adversary, might sway the risk-assessment of the predator.

When a large-bodied felid confronts the giant panda, the glaring dark orbs on a stark, intimidating face are a plausible form of confusion/intimidation.

Such encounters would seldom have occurred even prehistorically because of the natural scarcity of the giant panda compared to common prey such as sambar deer (Cervus unicolor), takin (Budorcas taxicolor) and wild pig (Sus scrofa). Hence the predators would tend not to be experienced enough to overcome their hesitancy.

Is there any other mammal worldwide – apart from the related spectacled bear – that shows a similar pattern for similar reasons but by independent evolution?

Possible candidates occur among South American anteaters (https://www.inaturalist.org/observations?taxon_id=53537 and https://www.inaturalist.org/journal/milewski/59344-why-even-the-jaguar-fears-a-mere-anteater# and https://www.theguardian.com/environment/radical-conservation/2017/feb/21/jaguar-giant-anteater-amazon-rainforest-camera-trap-brazil).

Anteaters, like pandas, flee and reproduce slowly owing to an energy-poor diet, and are therefore likewise vulnerable to predation. Although they lack teeth, their foreclaws are formidable because of the extraordinary power needed to excavate their main diet of social insects from wood and baked earth. Although small-brained and small-eyed, anteaters can be lethal in a vice-like clinch.

The giant anteater (Myrmecophaga tridactyla, https://www.inaturalist.org/taxa/47107-Myrmecophaga-tridactyla) again presents large felids (i.e. jaguar (Panthera onca) and puma (Felis concolor) with a dark patch on a whitish background – in this case on its wrist – to warn the would-be predator that sluggish does not necessarily mean vulnerable (https://www.dreamstime.com/royalty-free-stock-photo-giant-anteater-image25662955 and https://www.dreamstime.com/royalty-free-stock-photography-giant-anteater-detail-strolling-image39072067 and https://www.dreamstime.com/stock-photo-giant-anteater-adult-strolling-grass-image48467708 and https://www.dreamstime.com/giant-anteater-myrmecophaga-tridactyla-giant-anteater-myrmecophaga-tridactyla-also-known-as-ant-bear-image137426284 and https://www.dreamstime.com/royalty-free-stock-photography-giant-anteater-adult-strolling-grass-image39071997 and https://www.researchgate.net/figure/Segmentation-of-the-giant-anteaters-Myrmecophaga-tridactyla-body-showing-the-anterior_fig5_269667258 and https://www.aboutanimals.com/mammal/giant-anteater/ and https://www.dreamstime.com/stock-image-giant-anteater-image24206581 and https://www.dreamstime.com/anteater-cute-animal-brazil-giant-anteater-myrmecophaga-tridactyla-animal-long-tail-log-muzzle-nose-pantanal-brazil-image113787045 and https://www.dreamstime.com/stock-photography-giant-anteater-image20613402 and https://en.wikipedia.org/wiki/Giant_anteater#/media/File:Myresluger2.jpg).Is it mere coincidence that the dangerous foreleg of the giant anteater resembles the head of the giant panda? (https://www.boredpanda.com/anteaters-front-legs-look-like-pandas/?utm_source=google&utm_medium=organic&utm_campaign=organic and https://www.youtube.com/watch?v=kVuYGcs3OMA and https://www.youtube.com/watch?v=l6ngv3HGyjk and https://communicatescience.com/zoonomian/2009/01/29/antz-meets-kung-fu-panda/ and https://www.reddit.com/r/pics/comments/nmx1wi/have_you_ever_noticed_that_giant_anteater_legs/)

Now let us examine the red panda, which is relatively small-bodied but shows certain patterns in common with the giant panda, including slow reproduction and thus vulnerability to predation.

The red panda shows convergent colouration in its

  • dark legs,
  • noticeably pale face and dark markings on the ears and below the eyes, and
  • difference between the conspicuous anterior and inconspicuous posterior, with a brown rump and tail.

The red panda differs from bears in two relevant ways, as follows:

  • its starkly dark-and-pale ears are more conspicuous, relative to body size, than in any bear, and
  • it takes a pattern of darkness under the eyes that is present in subtle form in most bears and expresses it more clearly than in any bear apart from the giant panda.

Ear pinnae with dark and pale fur, arranged in a striking pattern, occur in various Carnivora. However, of all the 280 or more species in this order, the red panda has among the most conspicuous ears relative to the rest of the body and head. This is because the ears project sharply from the silhouette, have an eccentric lower tassel, have whitish rims and points, and present a contrast of dark versus pale on both the front and the back surfaces (https://www.timeout.com/melbourne/things-to-do/red-panda-encounters and https://kids.nationalgeographic.com/animals/mammals/facts/red-panda and https://www.alamy.com/stock-photo-red-or-lesser-panda-head-from-behind-showing-pale-ear-tips-china-30826963.html).

Indeed, the red panda takes all the various ways in which ears can be conspicuous across the spectrum of other carnivores, and combines them in one species. The resulting ‘auricular flag’ sets the red panda particularly apart from bears other than the giant panda, all of which lack any particular auricular colouration.

The giant panda and the red panda, although independently evolved, happen to converge in having conspicuous ears by different patterns. For among all bears, it is the giant panda that has the most conspicuous of ears. And the pattern in the red panda once again hints that the black upstanding ears on a white head of the giant panda aid conspicuousness rather than crypsis.

The fur around the eyes presents a parallel to the fur of the ears. Although the dark patches associated with the eyes of the giant panda are more defined than those of the red panda, there is a similarity in orientation and width there.

The following show that both the giant panda and the red panda similarly oriented dark patches associated with their eyes:https://www.dreamstime.com/portrait-panda-bear-close-up-cute-china-animals-close-up-view-panda-s-head-portrait-shot-portrait-panda-bear-close-up-image183719243https://www.dreamstime.com/stock-images-panda-image11134394https://www.dreamstime.com/stock-image-cute-panda-bear-walking-park-image36431751https://www.dreamstime.com/royalty-free-stock-photos-red-panda-close-up-image10652028https://www.dreamstime.com/cute-red-panda-exploring-portrait-close-up-portrait-curious-red-panda-walking-grass-exploring-image134067169

(writing in progress)

Posted by milewski milewski, June 03, 2022 21:34

Comments

Thanks for this very interesting article.

Posted by botswanabugs 4 months ago (Flag)

Thanks for this very interesting article. You made me think about Koala colourationm though its irrelevant to your article.https://www.newscientist.com/article/dn24682-zoologger-how-koalas-make-their-deep-seductive-grunts/

Posted by botswanabugs 4 months ago (Flag)

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