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Re: dinosaur endothermy??



In a message dated 96-12-05 15:36:32 EST, jonest@ava.bcc.orst.edu (Terry D.
Jones) writes:

> There is currently NO evidence for endothermy in dinosaurs.
> Unfortunately, regardless of the a large body of (obviously ignored)
> evidence to the contrary, the religious fervor about warm-blooded
> dinosaurs has not diminished. 

By the same token, there is currently NO evidence for >ecto<thermy in
dinosaurs. There is also NO evidence for >endothermy< in any >fossil< birds
or mammals. The latter are merely >assumed< to have been endothermic because
their living relatives and descendants are. Paul and Bakker note that
dinosaurs are most closely related to living birds, so the likelihood is that
dinosaurs were endothermic: the same reasoning that hypothesizes endothermy
in extinct birds.

The only >real evidence< of endothermy or ectothermy derives from the
systematic, day-to-day, hour-by-hour measurement of body temperatures of
living animals. Everything else, from predator-prey ratios to bone histology
to feathers to nasal turbinates to phylogenetic bracketing to growth rates,
is speculation. This is why the arguments will never end, and we will keep
going around in circles forever on this issue.