Hi there,
I found the answer at WhaleNet:
"You may have noticed that terrestrial mammals have the ability to
breathe through their mouths as well as the nostrils. Whales do not. A
full-blown mammalian yawn in the traditional sense requires this
ability to breathe through the mouth.
In a yawn, the movement of the jaws is what clears the ears, not the
passage of air/breathing. The stretch and relax thing is also facial
muscular and has nothing to do with the nose (or in the case of whales,
blowhole).
Technically, an acceptable definition of yawn is to simply to open
wide. If we segregate the breathing aspect of the conventional
mammalian yawn, whale do yawn. I've seen it in humpbacks, grays, and
orcas. Humpbacks sometimes get an object caught in the throat. It could
be a fish too large to fit down the hole or a piece of wood. They will
yawn (open wide) attempting to dislodge the inappropriate object from
their throat."
http://whale.wheelock.edu/archives/ask03/0240.html
The author of the answer is Pieter Folkens, who is:
- a bio-medical illustrator
- a marine mammal morphologist who designed the orcas in Free Willy
- a co-investigator at the National Marine Mammal Lab in Seattle
http://www.acsonline.org/conference/whales2000/artshow/ACS2000Artists.html
Search keywords: "whales yawn"
Best wishes,
robertskelton-ga |