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Re: Phorusrhacids killing large mammals in National Geographic Channel

A herbivorous diet for Diatryma was suggested by Andors in a series of
papers and presentations back in the late 1980s, but rejected by Witmer
and Rose in 1991:

Witmer, L.M. & K.D. Rose. 1991. Biomechanics of the jaw apparatus of the
gigantic Eocene bird Diatryma: implications for diet and mode of life.
Paleobiology 17: 95-120.

Augusto Haro wrote:
> 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?

Thomas R. Holtz, Jr.
Email: tholtz@umd.edu   Phone: 301-405-4084
Office: Centreville 1216
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
Fax: 301-314-9661

Faculty Director, Earth, Life & Time Program, College Park Scholars
Faculty Director, Science & Global Change Program, College Park Scholars
Fax: 301-314-9843

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
                        Building 237, Room 1117
                        University of Maryland
                        College Park, MD 20742 USA