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Re: Segregated vs age-mixed sauropod herds



On Mar 15, 2010, at 11:23 PM, John Bois wrote:

But you don't see lizards setting up creches (ostriches), arranging
multi-generational nest provisioning (crows), guarding offspring
through different growth phases (alligators), or teaching their young
how to compete in the global economy (community college adjunct
professors)...I'm saying that there are small differences among
clades, big differences between clades, and increasing complexity and
flexibility among clades with larger brains...and that this potential
goes to titanosaurs more than sea turtles.

Not sure how we'd define complexity, but in any case, there is a great deal of variation in parental care among vertebrates, and especially among those that have rather large brains and higher cognitive functions. I'm not sure this constitutes a "trend", though - you've thrown out a lot of interesting ideas, but very few of them seem to be rigorously tested. It is just as easy to produce anecdotal evidence suggesting that parental care has relatively little patterning, and/or that it has almost no relationship to time or phylogenetic position. It's an interesting thing to test, certainly, but until that time I remain skeptical that the parental care trends you allude to are real. I'm also not sure why we'd expect the potential for care to go more with titanosaurs than sea turtles (titanosaurs were not large- brained animals), nor am I clear on why we should expect that any animal that *can* provide care, hypothetically, actually will or did so. Overall, you've identified that parental care is common in crown group birds, crocodilians, and mammals. No arguments there, but I don't get the "trend" you're arguing for.

Cheers,

--Mike H.


Michael Habib
Assistant Professor of Biology
Chatham University
Woodland Road, Pittsburgh PA  15232
Buhl Hall, Room 226A
mhabib@chatham.edu
(443) 280-0181