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Re: Microraptor also ate fish



Excellent points there, sir.

I looked up a few papers about distinguishing scavenging from predation.
It's not promising. It's hard to demonstrate even in living species of
beetles using biomolecular markers. There have been attempts to measure
demographic age structure of prey animals exploited by hominins, and they
do seem to skew toward young animals, and they are different from the
distribution in non - hominin kill sites, but the statistics seem
inconclusive.

There is some work on distinguishing scavenged fish from predated ones in
fossils (McAllister, Predation of Fishes in the Fossil Record, Chapter 12
in Predator-prey interactions in the fossil record. edited by Patricia H.
Kelley, Michał Kowalewski, Thor A. Hansen. Springer, 2003). McAllister
notes that there are certain decay patterns in fish, where the
lepidotrichia and gills and head drop off first. He notes that a fish in
the gut with no head or tail is more likely to be scavenged.

Lastly I found a paper on salmon scavenged by otters and in Scotland. This
was a spawning run. It turns out that all of the scavenged ones were
males, no females died peacefully, all females taken were predated by
otters directly. The scavenged males were much much more likely to show
evidence of fungal infection. I doubt if this pattern would hold
everywhere, or we can tell from histology if Lycoptera were male or
female, or if we could find fungal hyphae or fungal chitin residues in the
fossils themselves. But you never know until you check.

Predation and scavenging of salmon carcasses along spawning streams in the
Scottish Highlands

FINAL REPORT FOR THE ATLANTIC SALMON TRUST. P. D. Cunningham, L. J. Brown
and A. J. Harwood October, 2002.




Jason Brougham
Senior Principal Preparator
American Museum of Natural History
jaseb@amnh.org
(212) 496 3544





On 4/23/13 1:50 PM, "GSP1954@aol.com" <GSP1954@aol.com> wrote:

>It is always possible that the fish were concentrated and partly
>immobilized in a drying pond, perhaps the remnant of a lake shoreline
>retreating for 
>one reason or another. That's how my buddy Todd and I captured a bunch of
>creek chubs running past by backyard during the east coast drought of
>summer 
>66. The problem with stomach contents is it is hard to know how a/typical
>they 
>are for a species (a really big sample size can help), and if it
>represented standard hunting techniques or occasional opportunity.
>
>GSPaul </HTML>