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Re: Partly-scientific answer to question about cats

Since this topic is reasonably relevant to dinosaur facial expressions (or the 
lack there-of), I 
suppose I'll throw in my 2 cents.

Whether or not any creature can smile depends very much on what you mean by 
'smile'. Dogs can 
certainly appear to turn the corners of their mouths slightly upwards when the 
mouth is open, 
however it's unlikely this is a direct attempt to communicate mood. An angry 
pit-bull with it's mouth 
open may well mimic a human smile as well (although perhaps more of a 'Jack 
Nicholson' smile 
than anything else). An over-heated dog with it's mouth hanging open may also 
mimic a smile, 
despite a neutral mood.

Smiling to communicate mood seems to be unique to humans. Other great apes 
don't seem to do 
it, despite facial muscles similar to ours. The facial expression we teach to 
chimps or orangs to 
mimic a big toothy smile in the movies is actually an expression of fear in 
wild apes. It's been 
suggested that the human smile is also a co-opted fear expression.

When humans smile, we seem to contract muscles between the corners of our 
mouths and our 
cheek bones, pulling the corners of our mouth upwards. Communicating using 
facial expressions is 
a subtle art however, depending on the context of other facial movements. A 
grimace of pain might 
also pull the corners of the mouth upwards, and a lunatic 'Jack Nicholson' 
smile may well 
communicate a mood quite different to friendliness. It's the complex and subtle 
combination of 
various facial movements that communicate mood in humans, and that 
differentiate honest 
emotion from the cold professional smiles of models, entertainers or 

Facial expressions in dogs and cats appear to be limited to movements of the 
ears, upper lip, and 
the eye region. It's no coincidence that many breeds of dog have colour 
differentiation above the 
eyes, which seem to be roughly analogous to our eyebrows. One of the reason why 
humans and 
canids have formed such a close symbiotic bond may be because both are able to 
interpret each 
others' facial expressions to a degree.

Archosaurs in general tend to have (or have had) even fewer facial muscles, 
making it unlikely 
that theropods ever curled their lips as menacingly as a canid (despite what 
you see in some 
movies), and reducing the chance of them ever smiling to virtually nill. 
Dinosaurs probably used 
body stance and vocalisation to communicate mood, much as modern birds do. 
theropods might also have raised their body feathers to increase their apparent 
size. Flushing 
blood into wattles, combs, or just bare skin might also have been a possibile 
means of visual 

Quoting Scott <hmwh@together.net>:

> We have a samoyed. They are known as the dog with a smile.

> ----- Original Message ----- 
> From: "PLDT FOA- Edmundo S. Ancog" <rayancog@pldtdsl.net>
> I;ve always thought that, in order to smile the way humans do, a mammal
> would have to: a. have the muscles to pull the lips upwards; and b. have
> cheeks wherein the mouthline doesn't extend past the front teeth. While
> ungulates, rodents and lagomorphs have cheeks (some with well-developed
> cheek pouches), carnivores like my pet dogs have mouthlines extending all
> the way to the molars. Dogs can pull their raggedy lips upward, and looking
> at pictures of cats all over the Internet it does seem that they are capable
> of doing so, although to a lesser extent. Their faces are also foreshortened
> compared to the average dog breed, so they have fewer muscles and a shorter
> mouthline to begin with, AFAIK.
> It makes me wonder now where Lewis Carroll got the inspiration for the
> grinning Cheshire Car.


Dann Pigdon
GIS / Archaeologist              http://geo_cities.com/dannsdinosaurs
Melbourne, Australia             http://heretichides.soffiles.com