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Re: My Gr. 9 Science Fair Project: Questions



Paul Willis said:

>[...] sooner
>or later every hadrosaur would have to go near croc-infested water for a
>drink. Once there, they would be fair game for those naughty little buggers
>measuring up to 14 metres or more in length.

>What is it with you and the bloody crows? Just because you can find an
>example of a complex behavious in one group of animals does not mean that
>you can invoke it to prop up your argument for another.

Actually, it's the crows I couldn't bloody that impressed me!

>Parsimony would
>have us take a more sedate line in reconstructing hadrosaur-crocodile
>interspecific activities: the closes analogue of that situation appears to
>be herding mammal-crocodile interelationships occuring in modern Africa.
>There the herding mammals, despite their numbers and communication
>abilities etc etc, still fall prey to lurking crocs and the same is
>probably likely for the hadrosaurs and crocs all those years ago.

Well, some say it's a big jump from dinosaurs to mammals, but okay.  Am
I right that modern African herd animals are in no danger of extinction
from the croc scourge?  Do relatively few meet their fate in the jaws of
a croc?

Wouldn't parsimony suggest the same relationship between hadrosaurs and
crocs?

It sounds like the relationship between crows and farmers!

>Stone the bloody crows!

I considered it, but I couldn't even hit them with bullets!

>Again, going back to a reasonable modern analog, modern
>herding mammals will enter the water, in large groups, to drink or to cross
>the water body. In these situations, they are vulnerable to and sucumb to
>predation by crocodiles. Rarely, if ever, will the enter water to escape
>predators because predators can follow them into the water and because they
>risk the chance of being eatern by crocodiles. The level of predation by
>crocs in these situations represents a significant pressure on the herd
>dynamics of modern herding mammals. It is reasonable to assume that a
>similar situation occurred for herding dinosaurs living with larger
>crocodiles in the late Cretaceous.

Great!  We're back to Della's question from two weeks ago!

Crocs eat meat and swim fast with their big tails.  African herd mammals
eat plants and swim slowly with their hoofs.  Duckbills had big tails.
Does parsimony dictate that because they ate plants, they must have swum
as slowly as modern herd mammals?

Thanks for your remarks.

- Stephen Throop