Re: Phorusrhacids killing large mammals in National Geographic Channel

[Augusto Haro <augustoharo@gmail.com>]

Now thinking on what Gastornis (Diatryma) ate. Admitting the lack of
the downcurved tip suggests it would not eat animals wider than its
gape... (for most carnivorous/scanvenger birds eating prey in pieces I
know seem to bear these tips, e.g., raptorial birds, cathartids,
skuas), and the powerful bite was not used aginst hypothetically large
seeds... what if the powerful bite was used to break tree branches in
order to reach fruits/distal leaves? Elephants do so, and it is
difficult to me to find other adaptive explanation (assuming there is
one) for their tusks (ignoring intraspecific combat/sexual selection).
Alternatively, the beak is somewhat shovel-shaped, so what if they
used it to unearth tubercles/small animals. This may require some
force, overall if the adductor musculature is employed in the digging,
and pigs have also strong bites. Anyway, I think powerful jaw muscles
do not only have to suggest hyaena-like bone-cracking. Gorillas and
pandas provide other examples of powerful bites directed against
bamboo.

Regarding the question of whether the downcurved tip of the upper jaw
of phorusrhacids implyied carnivory: are not the most prominent of
these beak tips present in macaws?