Differences in facial expression between wolf and domestic dog

An important difference between the wolf (Canis lupus) and the domestic dog (Canis familiaris) is the appearance of the eyes in a direct look at humans.

In the wolf, the eyes are stark, i.e. they stare with an  ‘in your face’ colouration pattern, i.e. aggressive/dominant/assertive.

By contrast, in the domestic dog, the look is softer and more receptive, because there is not the same dark/pale contrast between the eye and the rest of the face. For example, in an otherwise rather wolf-like breed, the German shepherd, the eyes are less conspicuous than in the wolf because

  • the iris is not pale and therefore does not contrast with the dark eyelids, and
  • the pelage around the eyes is not pale.

(The dingo is intermediate, something that I’ve never seen pointed out about the dingo.)
  
Look at a wolf, and one sees something ‘inhuman’ and ‘beyond pity’. The appeal is only the thrill that such savagery can somehow persist in the far corners of today’s tame world. By contrast, look at a wolf-like domestic dog, and you see a ‘human’ face, full of pathos, empathy, and appeal.
 
I have chosen the two photos below to present this contrast succinctly.
 
The following portrait of the wolf is typical.
Canis lupus adult:
http://i.huffpost.com/gen/1156449/images/o-WOLF-facebook.jpg

The eyes stare starkly (balefully) because of the dark/pale contrast between iris and eyelids, and the further contrast between the whole eye and the pale face. The whole effect is somewhat counterintuitive, because if I stated that the wolf had both a pale iris and a pale face, one would not really expect the eyes to be particularly conspicuous. But the reality – partly owing to the dark eyelids – is that the eyes do stare conspicuously.

The wolf is taken to be the direct and sole ancestor of the domestic dog. However, photos of the 800 breeds of the domestic dog show that there is virtually no breed possessing this stark stare of the wolf. I suspect that this is partly because an extinct species other than Canis lupus is the real main ancestor of the domestic dog, with variable contribution from C. lupus in certain breeds. I accept that the stare has been selectively bred out of the wolf to produce an animal more empathetic and communicative with its human associates.
 
Many readers may find something wolf-like about the German shepherd.
Canis familiaris adult, German shepherd breed:
http://thumbs.dreamstime.com/z/german-shepherd-closeup-771297.jpg

However, the pattern of the face, with particular respect to the eyes, is quite different. The iris is now dark and so is the face. Because the eyelids remain in their original dark condition, all dark/pale contrast about the eyes is eliminated. The dog can look straight at the human now, without any impression of staring. As I will show in another Post soon, the dark muzzle of the German shepherd is actually a puppy-face in the ancestral species, which has been fixed in the domestic dog in a process akin to neoteny.

The closest thing in the wolf to this kind of face is that of the infant wolf at the stage just after its eyes have opened for the first time, a stage at which of course there is nothing but dependence and no hint of aggression or dominance. In many breeds of the domestic dog, the medial eye-whites will also show to some extent in a direct look such as we see in this photo. Such displays of the eye-whites are minimal in the adult wolf, and this is another element of similarity to humans that has been inadvertently bred into the domestic dog, and even into the dingo to some degree.

A further point to note is that the ‘eyebrows’ have been accentuated in the domestic dog compared to the wolf, further elaborating the empathetic facial expressions of the domestic dog.

At first glance there may seem to be little difference between the wolf Canis lupus (left, below) and the husky dog Canis familiaris (right, below).
 Canis lupus adult (left); Canis familiaris adult (right):
http://www.crazynauka.pl/wp-content/uploads/2013/01/tumblr_mh8svukENw1rafcg9o1_1280.jpg

However, in the wolf the eye language among adults is simple: an on-or-off stare. A stare is dominant and aggressive, and the alternative is simply to look away. The colouration of the eyes of the wolf, as explained by Ueda et al. (2014), accentuates this effect. The iris is pale and the eyelids and corner of the eye are dark, creating a stark-enough effect in terms of a stare. In addition, I have noticed something that Ueda et al. (2014) possibly did not notice, that the iris-edge in the wolf is dark too, in a way that is imperceptible in the stare but which helps to exclude any eye-white-display.
 
In the domestic dog, the pale iris of this breed (husky) may not be the same paleness as in the wolf. Instead, it may represent the infant of the wolf (https://www.companionanimalpsychology.com/2015/01/do-hand-reared-wolves-get-attached-to.html), in line with various other ways in which the domestic dog is infantilised relative to the wolf. Furthermore, in its interactions with humans (i.e. interspecifically rather than intraspecifically), the domestic dog does use its eye-whites (to varying extents depending on the breed) to produce facial expressions. These expressions are qualitative in contrast to the ‘quantitative’ (on/off) stare: they convey nuances of meaning along the lines of an ‘eye language’ to which humans can relate, even if the wolf cannot. And, probably overlooked by Ueda et al. (2014), the edge of the iris in the pale-eyed breeds/individuals of the domestic dog is not dark – although this difference is hard to spot in the photo-pair below.
 
There are also other, surprisingly large, differences between C. lupus and C. familiaris in their eyes and vision. The wolf has a horizontal streak in its retina, useful for scanning the horizon for movement. Depending on the breed of dog, this streak has been inadvertently reduced by selective breeding in C. familiaris, making the visual system somewhat more similar to that of the human in emphasising binocular vision and an ability to concentrate on an object in front of the animal.
 
So the bottom line is that, despite the apparent similarity shown in this photo-pair, the eyes and vision of C. lupus (putative ancestor of the domestic dog) and C. familiaris are more different than one might expect in two species that can still interbreed freely. In a sense, the domestic dog is a ‘human-eyed wolf’. Canis familiaris is deeply, not superficially, domesticated, as revealed by the details of its eyes and vision.

Publicado el jueves, 30 de junio de 2022 a las 09:11 AM por milewski milewski

Comentarios

One difference between the wolf (Canis lupus) and the domestic dog (Canis familiaris) is that the domestic dog is born with its adult facial colouration in almost all breeds, whereas in some cases the wolf has a dark ‘puppy face’ that is lost as the juvenile grows. It is the puppy-face which has been retained into adulthood via selective breeding along ‘neotenous’ lines, in those breeds that have dark faces in adulthood.
 
Canis lupus infant, showing dark muzzle unlike adult:
http://global.fncstatic.com/static/managed/img/fn-latino/lifestyle/Mexican%20Wolf%20cub%20close-up.jpg
 
Canis lupus infant, showing that in the ‘puppy’, just after the eyes open, the muzzle remains dark as the cheeks become pale.
http://2.bp.blogspot.com/-IkXceMinYRs/Uy895uZsaII/AAAAAAAAkdc/qosnk_T_dJY/s1600/946509_593102990723604_321859455_n.jpg
 
Canis lupus juvenile retains darkish muzzle for some time as it grows.
http://www.visualphotos.com/photo/1x10414455/close-up-of-gray-wolf-pup-looking-up.jpg
 
Canis lupus juveniles at the following stage have nearly lost all the darkness on the muzzle, their facial pattern approaching that of the adult.
http://thumbs.dreamstime.com/z/wolf-mom-pups-close-up-wildflowers-playing-puppies-field-daisies-48176533.jpg

German shepherd juveniles share the dark muzzle at birth but retain this into adulthood:
https://www.expatads.com/adpics1/2015/3/German-Shepherd-Puppies-Now-Available-at-amandalouic-G-M-I-L-C-O-M-55134b9468d4d3511049.jpg

Anotado por milewski hace más de un año

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