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

Re: Dinosaur egg-laying contributed to extinction?

> Do we really know how much parental care the K mammals
> really
> invested in their young? Is'nt it possible that the early
> placentals
> (not to clear on when placentals get their start and if the
> K-T
> boundary ones were 'early) produced live-birth young that
> were pretty
> self-sufficient?

Seeing as how all living mammal species produce milk, from monotremes, to 
marsupials, to placentals - and those groups diverged long before the K-Pg 
extinction - one must assume that Mammals in the Cretaceous produced milk, and 
thus fed and cared for their young to a large enough extent that mammary glands 
were conserved in all the lineages that lead to the crown group.

> Problem there is things like crocodiles. Or sharks. Or
> anything
> producing a larval form (which, very similarly to things
> like
> sauropods, had young that occupied very different niches
> than adults).

Yes, but I don't think anyone is arguing that this was the sole criteria for 
survival. For example, such creatures generally have low metabolic rates