[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
RE: Campbell's even crazier than a MANIAC? (archeopteryx climbing)
Quoting Tim Williams <email@example.com>:
> Eric Boehm wrote:
> > So my related question is: Is there a fundamental superiority to Mammalian
> quadruped predators that
> > resulted in them outcompeting the Biped "terror birds" (really the closest
> thing after the KT to a classical
> > dinosaur), or was it an accident of geographhy?
> Maybe the success of predatory mammals vs predatory birds has more to do with
> teeth, rather than bipedality vs quadrupedality.
My guess is that reproductive strategies may have given the mammals an
advantage. Birds can try
to defend a nest, but if they instead choose to run away then their eggs remain
'sitting ducks'. A
pregnant sabre-tooth however could run away with it's precious unborn (but not
safely inside it. Once the cubs were born (so no longer borne), a mother could
bed down with them
while they were especially vulnerable and produce milk from her own reserves
for a while,
reducing the cubs' visibility to predators.
Terror birds would have had to search for food for their hatchlings as soon as
they'd fully absorbed
their yolk sacks. If they raised chicks in pairs, then they may have been able
to have at least one
parent on guard duty at all times. However if the parent (either male or
female) raised the chicks
alone, like emu males do, then foraging for food would have required either
leaving the chicks
unguarded for a while, or the chicks to forage with the parent (the latter
increasing their visibility
and improving the odds of predators spotting them).
Sabre-tooths may also have been able to excavate den sites for their young to
hide in once they
were born, and to run too once they got old enough to be mobile. I suppose
having a functional set
of forelimbs capable of digging helps in that respect.
GIS / Archaeologist http://geo_cities.com/dannsdinosaurs
Melbourne, Australia http://heretichides.soffiles.com