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Re: Novel invasion of dino-haven by K/T mammals.



John Bois writes;

>Perhaps the quality is more important than the
>quantity of neurons.
>Denied light, the mammals diencephalon ballooned around the olfactory
>area of the brain.

Ummm...

To my knowledge, mammals were "in the dark" for most of the Mesozoic.  If
 anything, the increase in mammalian brain size is due to the first
 incidents of active hunting by small theropods, like Troodon.  Also, an
 increase in the nasal-sensing power of the brain doesn't necessarily
 correspond with an increase in cognative ability.

>What part of Troodon's brain ballooned?

AFAIK, every aspect is bigger, relative to other dinos.

Also, a
>possibility is that social behavior was adaptive--animals who are
>subjected to long harsh periods of predation tend to develop social
>adaptations.  Look at ants, bees.  Naked mole rats even have a kind of
>queen bee, a female who is the only breeder in the colony.

The problem with this hypothesis is that mammal predation may have been a
 Cretaceous invention.  Before Troodon, small theropods would've eaten just
 about anything, where small mammals would make only one entree in the whole
 extensive buffet.  It was only at the evolution of the small dromaeosaurs
 that extensive mammal hunting occured; so there just isn't enough time to
 form an extensive social structure by the end of the Cretaceous.


>Mammals, and perhaps birds too, caused a summation of egg _and_ juvenile
>predation to the point whre there were more dying than being born.

Again, the idea of an insectivore being able to effectively bite through a
 dino eggshell is very difficult to believe, and they're probably the best
 equipped for the job (imagine a field mouse trying to eat an ostrich egg).
 Mammalian egg predation is most likely a myth.

Rob

***
"Perhaps if we made a large wooden badger."
        -MPATHG