>Marc, please see my latest messages, walruses definitely have air sacs
attached to the pharyngeal anatomy, which are inflated while at rest
Yes, thanks, DD, very interesting. Only in males? Air sack or food sack?
Zenker's diverticle in humans is also more frequent in men.
>I don't know if they are anatomically similar to ventricular
or non-ventricular laryngeal air sacs in primates and ungulates. I
don't know if other seals, sea lions, sirenia or cetaceans have them
or use them in a similar manner. I don't know if walruses use these
air sacs during vocalization in water or out of water, or if they use
them for anti-hyper-ventilation. It is possible though unlikely IMO
that they use them as food storage pouches (like baboons).
I don't think this is so unlikely: food storage sacs connected to the
foodway (not airway!) are not rare: OWMs, many rodents, pigeons, pelicans...
But multiple functions (at the same time of subsequently) are likely.
>I think we
need to verify that hooded seals only use them above water, the nasal
use underwater is not well understood AFAIK, but could be useful for
equalization at greater depths, this would not necessarily require
very large nasal sacs, even very small ones might work. Since no
aquatics except Homo use hands to pluck and to hold air pressure in
the nose during equalization, other aquatics probably use multi-valve
internal air compression and decompression valving. DD
> > The only specialized carnivore with large inflatable air sacs is the
> > walrus AFAIK. I don't know if its air sac differs from ape and
> > underwater IIRC. DD
> > Do they really? Is the noise made by exhaling as in land
> > noises made by dolphins made by exhaling? How is the transmission
> > sound affected by travelling through water instead of air? Elaine
> I didn't know walruses have airsacs.
> Hooded (=bladder-nosed) & elephant seals have inflatable noses (only
used outside/above the water?). --Marc