Tyrannosaurs and Hyenas

[Sim Koning <simkoning@msn.com>]

 I know this is probably old news for most of you, but I watched the 
discovery channel documentary on T-rex and read Horner's book and wanted to 
write some of my feeling on the matter of scavenging. I'm new here, so let 
me know if this is something people are tired of discussing.

 Those in favor of a scavenging life style for tyrannosaurs often draw a 
comparison between tyrannosaurids and hyaenids. While it is true that 2 of 
the 4 hyaenid species are mostly scavengers, the largest member of the 
family, the spotted hyena, is considered by many to be the most effective 
and most intelligent predator in Africa. The 2 scavenging species, the brown 
and striped hyena, are not purely carnivorous. Both scavenging species are 
actually opportunistic omnivores that supplement their diets with fruits, 
vegetables and insects. The brown hyena also represents the largest land 
animal that lives primarily on carrion and it is smaller than the spotted 
hyena. Is it realistic to claim that a Tyrannosaurus could live primarily on 
carrion when it was one of the largest land carnivores in the history of the 
planet, not to mention one of the largest animals in its ecosystem!

 It is worth mentioning that the suspected tyrannosaur coprolite is filled 
with undigested bone fragments. Hyenas, as an adaptation for scavenging, can 
consume and completely digest bone. The fact that tyrannosaurs lacked the 
ability to digest bone (like owls) suggests that they were not specialized 
scavengers. Though they may have chewed smaller animals and certain body 
parts, I doubt that they made a habit out of swallowing large chunks of bone 
unless they were able to regurgitate them later. The only large land 
vertebrates that live entirely on carrion are vultures and other scavenging 
birds. Since these birds fly and are often much smaller than the predators 
of their ecosystem, they are hardly analogous to giant 6 ton bipedal 
theropods.

Now I respect John Horner, but I just don't understand why he keeps pushing 
the scavenger hypothesis when so many facts are against it. Tyrannosaurus is 
one the most important fossils because it inspires the minds of children and 
gets them interested in science. Is there really a point in trying to turn 
what was a fast and powerful predator into a lumbering scavenger if there is 
no real evidence for it?

Simeon Koning

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