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From: friesen@psivax.UUCP (Stanley Friesen)
Newsgroups: net.bio,net.origins
Subject: Re: Bipedalism
Message-ID: <1128@psivax.UUCP>
Date: Wed, 23-Apr-86 15:16:45 EDT
Article-I.D.: psivax.1128
Posted: Wed Apr 23 15:16:45 1986
Date-Received: Sun, 27-Apr-86 06:28:15 EDT
References: <487@bcsaic.UUCP> <1002@cybvax0.UUCP> <32@sphinx.UChicago.UUCP> <1109@psivax.UUCP> <71@sphinx.UChicago.UUCP>
Reply-To: friesen@psivax.UUCP (Stanley Friesen)
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In article <71@sphinx.UChicago.UUCP> beth@sphinx.UUCP (JB) writes:
>
>My mistake - sorry for the misinformation.  Just out of curiosity,
>what creatures preyed on early Hominids, and how do we know?

	Lions, Hyenas, and Sabre-toothed cats. We know because we have
found a number of early hominid bones with tooth-marks on them which
match these species. One rather remarkable Autralopithecus skull has
four holes in it space just right for the canines of some known
carnivore(a Sabre-tooth I think). Apparently the cat had dragged the
Ape-man by it head to its lair to eat it!

> Same
>question(s) for Ornithopods.  (Sorry for my ignorance here - I'm
>just a casual reader.)
>
	With the Ornithopods it depends on *which* ones and when.
Among the predators on these forms were such animals as Tyrannosaurus,
and Deinonychus. It is also possible that Allosaurus preyed on some
members of the group. How do we know? Well, tooth-marked bones are
known for dinosaurs too. Also, at least some Ornithopods showed flock
nesting behavior(some mass nest sites have been preserved, there was a
Scientific American article on this last year). This kind of nesting
behavior in living animals is usually a form of defense against
predators. Then of course there is the evidence of the speed adaptions,
such as long legs, weight supported on the toes, and light build,
in certain small ornithopods(Dryosaurus, Hypselophodon &c), again
usually associated with escape from predation in living *herbivires*.
It is also possible that the heavy, spiked thumb of Iguanodon was a
defense mechanism against predation.
-- 

				Sarima (Stanley Friesen)

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