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

Re: attack on dinosaur--horrific video

----- Original Message ----- From: "David Marjanovic" <david.marjanovic@gmx.at>
Racoon-size? How pathetic.

_Nanocuris improvida_ and _Cimolestes magnus_, both carnivores (apparently) and both eutherians, and both "marmot" sized. Again, my point is that mammals of this size (and even smaller) scale to non-avian dinosaurs offspring in similar ratios as extant predators (mice vs. albatross, for example) scale to extant dinosaur offspring. They may or may not have been a problem before the boundary--it _is_ an interesting coincidence regardless.

I will just bring up *Repenomamus giganticus* again, which must have ushered in the Great Barremian-Aptian Boundary Mass Extinction, except it somehow didn't.

Anne Weil discusses this anomally, saying research is going on trying to find out if dinosaurs at that place and time were smaller than usual. Certainly there are selection pressures for being large or small. What were they in each case? Dinosaurs were not smaller in the late K. Also, _N. improvida_ and _C. magnus_ were very different creatures from _R. giganticus_. I don't know that much comparison is afforded--other than the interesting question of relaxation on size constraints enjoyed by both clades, likely for different reasons.

Not even the crocodiles died out.


Are you certain that ground-nesting birds are generally night-blind?

I know an attended ostrich nest is practically immune from predation in the day--but that, if discovered by black-backed jackals, they are invariably destroyed at night, i.e., the ostrich can defend effectively in the day time but not at night.