Have you ever noticed that, when carnivores yawn, they can yawn really, REALLY wide? Like, say, a good 90 degrees? A sobering sight to ponder, eh? Not least when seen head on.
Herbivores don’t seem to achieve such an impressive gape, but then, perhaps I simply haven’t seen a really good one.
So, fellow Dopers, associates of carnivores, herbivores, and omnivores, got yawns to share? 
Hippos can open pretty wide.
I’d say a hippo’s yawn isn’t anything to sneeze at. Rats look to have a nicely sized yawn, too. Horses, though, only have the size of their teeth going for them.
And on preview I see I’ve been beaten to the hippos. Drat!
Baboons have quite impressive yawns. (There are 3 images of yawns on that page.)
Is anyone else yawning repeatedly while viewing this thread?
And horse bites hurt! Damned horse thinks it’s funny to nibble on me. I’ve still got a bruise on an… um… sensitive part of my anatomy. Okay, fine, she bit me on the boob. But you’re not getting a picture.
-Lil
Not until now, dammit.
I’m not female, but I’m going “OWW! OWW!! OWW!!” about right now.
And thank you for not posting pictures.
At least not until the bruises heal. 
Urf. I was yawning before I opened this. Now they’re getting painful and coming faster.
yaaawn
You can thank me, too, for not posting pictures of my thumb tip after a horse bit it. OW OW OW!!! Fortunately he released it the instant I screamed, so it’s still attached to the rest of me.
Probably because lettuces rarely put up a good fight.
There’s a whole website devoted to pictures of yawning animals!
Oh. My. GAWD.
But, actually, you make a good point: What the critter eats, and how it acquires it, would of course dictate the structure and capacity of the jaws and the surrounding flesh. A carnivore would need the wide gape to up the odds of it getting hold of its prey. An herbivore can afford to take small bites, and needs a long row of powerful molars to grind up its browsed roughage – molars whose encasing muscles and skin simply can’t stretch all that wide.
Yawning bunny!
http://www.venushairhouston.com/animallovers/bunny-yawn.jpg
