I read something like that a while back but I think it was referring to some kind of enormous sea turtle. A res can hold it's breath roughly 15 min while awake and up to 3 hours while sleeping.
The things that come to those who wait may be the things that were left by those who got there first - Steven Tyler
Turtles can hold oxygen in their body tissue. I've read that some can stay under water for 30 minutes. Guess the best one to know this answer is the turtle.
My babies: Tanner (RES), MR. Prissy & Ringo (budgies), Shinju (cockatiel)
"Little dudes are just eggs, we leave 'em on the beach to hatch, and then — koo-koo ka-choo! — they find their way back to the Big Ol' Blue"
They have membranes under their throats and near their cloacas that allow them to absorb oxygen from the water (would make sense during hibernation). If they're active, however, I've read info that was more or less similar to that above.
"You become responsible, forever, for what you have tamed." -Antoine de Saint Exupery-