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RE: Predation in fossil record?



> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Bruce Woollatt
>
> Hi all,
>
> The current flap over Horner's " Big Stinky Scavenging T.rex"
> claim got me
> to thinking. Apart from the "fighting dinos" and the munched
> Edmontosaur who
> lived to talk about it, what other evidence of actual hunting behavior is
> there in the fossil record? If there were not extant examples of wolves,
> lions, tigers (insert name of any predatory animal here) etc.,
> how would we
> "know" that they hunted at all? How would we know if an animal scavenged
> without reference to living examples? Dentition certainly indicates diet,
> but perhaps not neccesarilly means of acquiring food.  Can these be
> distinguished in the fossilsl?  Much of Horner's assertion for scavenging
> seems to be based on personal incredulity (arms, eyes seem to him
> to be too
> small  to be used for hunting) rather than evidence. I would
> think that the
> best you could doin the absence of evidence for a fossil
> creature's behavior
>   would be to say you're not able to decide which was used.

Excellent questions, discussed (in part) in:
Holtz, T.R., Jr. 2003. Dinosaur predation: evidence and ecomorphology. Pp.
325-340, in P.H. Kelley, M. Kowalewski and T.A Hansen (eds.), Predator-Prey
Interactions in the Fossil Record, Topics in Geobiology Vol. 20. Kluwer
Press.

Farlow, J.O. & T.R. Holtz, Jr. 2002. The fossil record of predation in
dinosaurs. Pp. 251-266, in M. Kowalewski & P.H. Kelley (eds.), The Fossil
Record of Predation. The Paleontological Society Papers 8.
PDF at http://www.yale.edu/ypmip/predation/Chapter_09.pdf

And you've hit (part of the) problem right on the head.  Also, successful
predation and scavenging leave identical traces in the fossil record (except
in the case of the second, third, and nth scavenger at a corpse, where the
tooth marks would cross-cut older marks).

We can find occasional remains of unsuccessful predation attempts, to show
assaults on living prey items.

But, by and large, evidence for predation (or against predation) is
ecomorphological: using comparative anatomy, biomechanics, and the like to
compare fossil forms with modern analogs.   With all the caveats that that
holds...

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796