If they were warm blooded, perhaps a layer of blubber.
Perhaps not. Blubber is pretty much a mammalian invention (at least among
living animals). There is, though, a reptilian equivalent. The
leatherback turtle, which ventures into some pretty cold waters, has an
oil-suffused subcutaneous layer of tissue that seems to be the ecological
equivalent of blubber. Leatherbacks - or at least the adults - are pretty
much functional homeotherms, relying on their size, the oily insulating
layer, and a countercurrent exchange system in their flippers to keep their
body temperature elevated. I would not be surprised if the much larger
pliosaurs, for example, were able to do the same.
--
Ronald I. Orenstein Phone: (905) 820-7886
International Wildlife Coalition Fax/Modem: (905) 569-0116
1825 Shady Creek Court
Mississauga, Ontario, Canada L5L 3W2 mailto:ornstn@home.com