Differences among wolf, dhole, and African hunting dog in emphasis of stare
@tonyrebelo @jeremygilmore @davidbygott @maxallen @beartracker @douglasriverside @ludwig_muller
The wolf (Canis lupus), the dhole (Cuon alpinus), and the African hunting dog (Lycaon pictus) are approximate ecological equivalents in different regions. All are gregarious predators of ungulates, forage in a typically canid way, and have complex social organisation.
These belong to three different genera. However, one might think that the appearance of the eyes – so important in intraspecific communication – would be similar regardless of the various details of their generic differences.
The surprise is that the three species differ radically in the conspicuousness of their eyes, something that has never been explained.
As readers can see in the photos at the end of this Post,
- the wolf has a conspicuous stare (https://www.offset.com/search/wolf+face),
- the dhole has a neutral appearance to its eyes (https://www.reddit.com/r/pics/comments/6cml4q/the_dhole_cuon_alpinus_also_known_as_the_asiatic/), and
- the African hunting dog masks its eyes (https://www.mindenpictures.com/stock-photo-african-wild-dog-head-portrait-lycaon-pictus-southern-africa-naturephotography-image90201630.html).
Why would such a basic form of communication differ so much among apparently analogous animals all belonging to a single family?
Here are some clues.
I notice an inverse relationship w.r.t. the ear pinnae, as explained below.
Where the eyes are hidden, the ear pinnae stand out particularly clearly. This suggests that the African hunting dog in particular ‘stares with its ears’ (https://www.alamy.com/close-up-portrait-of-an-african-wild-dog-or-painted-wolf-lycaon-pictus-in-mana-pools-national-in-the-zambezi-valley-zimbabwe-endangered-species-image387700136.html and https://www.agefotostock.com/age/en/details-photo/african-wild-dog-lycaon-pictus-adult-close-up-of-head-resting-on-sandy-grass-area-okavango-delta-botswana/FHR-10354-00389-827).
The social hierarchy is strongly enforced in the wolf (partly owing to seasonal breakup and reuniting of the group), and less so in the dhole and African hunting dog.
In the African hunting dog it is males that stay in the natal group, whereas in the wolf it is females. To my mind, the role of males in Lycaon, as reproductive helpers, shows that they are even more altruistic than is true for the wolf. Does this help to explain their lesser need to keep using facial expressions to assert their authority?
Unlike the situation in the wolf, the hierarchies are separate for male and female in the African hunting dog (https://en.wikipedia.org/wiki/African_wild_dog).
In the case of the dhole, there seems to be an intermediate situation (https://en.wikipedia.org/wiki/Dhole): the species, relative to the wolf
- is less territorial,
- has less seasonally variable habitats,
- has a less strictly-enforced social hierarchy, and
- has less marked submissive behaviour.
There is already an inkling of these differences in the literature, but what is new here is this:
There seems to a gradation in substitution by the ear pinnae. Cocked ears are somewhat assertive, but less so than staring eyes owing to the more vague directionality of the ears. An 'ear-stare' is more polite than an eye-stare, hypothetically suiting the more altruistic species.
In summary:
Wolf, dhole and African hunting dog differ in facial expressiveness despite being gregarious predators with complex cooperation in foraging and reproduction. This is because the social hierarchy is most strictly enforced and renewed in the wolf, whereas assertive vs submissive behaviour is less expressed in the African hunting dog.
The new understanding I offer here:
The conspicuousness of the eyes and ears in wolf, dhole and African hunting dog vary inversely, in keeping with the general expressiveness of the face in these species with varying levels of enforcement of a social hierarchy.
In the wolf, the stare is emphasised by the pale iris and dark eyelids (https://www.istockphoto.com/photo/wolf-portrait-gm588348958-101010441?phrase=wolf%20staring and https://www.istockphoto.com/photo/staring-wolf-gm1270419883-373373499?phrase=wolf%20eye%20close%20up).
In the African hunting dog the eyes are masked but the ears are conspicuous instead.
The dhole is intermediate.
ILLUSTRATIONS
In the wolf, the eyes stand out from the face because the iris is pale enough, and the eyelids dark enough, to provide tonal contrast against the rather nondescript background of the face.
Canis lupus adult:
http://thumbs.dreamstime.com/x/timber-wolf-portrait-9065736.jpg
https://www.canstockphoto.com/wolf-1858057.html
In the dhole, the eyes are not accentuated by tonal contrast, so that there is no emphasis of the stare whatsoever. Instead, if there is any aspect of the face that is instantly noticeable, it is the ears, which possess conspicuously pale ear-feathers.
Cuon alpinus adult:
https://www.flickr.com/photos/john_kuk/2543678348
http://img12.deviantart.net/7a87/i/2014/100/a/d/the_red_dhole_by_picturebypali-d7dvyov.jpg
https://www.activewild.com/dhole/
https://www.alamy.com/stock-image-dhole-or-asiatic-wild-dog-166396295.html?imageid=6FF471E9-C95C-4978-B09C-F233A80F9018&p=68495&pn=1&searchId=82f8b24b994b3a716b7ae79f6f2bf1d9&searchtype=0
Finally, in the African hunting dog, the eyes are actually masked. This could hardly be more different from the wolf, because not only is there no dark/pale contrast between iris and eyelids, but the iris is so dark that it is hidden in the dark fur surrounding the eye. Although the ears are not adorned, they are so large and dark that they dominate the countenance, emphasised by their dark/pale contrast with the forehead/temples.
Lycaon pictus adult:
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https://tranquiljourneys.tours/flora-fauna/african-wild-dogs/
The spotted hyena differs from canids in its facial expressions. More particularly, it tends to show its eye-whites.
Crocuta crocuta juvenile:
https://s3.amazonaws.com/photos.safaribookings.com/library/zambia/xxl/Liuwa_Plain_National_Park_023.jpg
@milewski well done on another fascinating Post!
Zimen (1978) hints that male wolves can prefer to stay on as helpers where the alpha pair are their relatives/parents, rather than leaving and starting another pack. This would ensure pups containing their genes are produced while avoiding the hard work of becoming and staying alpha male, mating etc.
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