[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: The Biggest Dinosaurs

On Thu, 21 Aug 1997, Sam j hogan wrote:

> There is strong evidence that viviparity  (or actually,
> oviviparity) in snakes is more strongly connected with arboreality.  This
> includes many snkaes not normally thought of as arboreal; an increasing
> body of evidence indicates that many snakes spend at least part of their
> time in trees.  This  *MAY*  also have something to do with the relative
> sizes of species.

Yes, and de Fraipont et al close their article by saying that while "egg
guarding and viviparity seem to be independent, almost antagonistic,
evolutionary events, a similar analysis on a larger sample size and using
more life history traits would be necessary to fully support this
prediction."  If they could control for arboreality...  But, actually they
say that viviparity is most often correlated with cold climate.
        Anyway, just to clarify, the following categories of
snakes and lizards were compared with regard to size in the same genus:
Oviparous (without guarding) vs. Viviparous  Result: V shows a reduction
in size. Oviparous (without guarding) vs. Guarding  Result: Egg guarding
species are bigger.