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Re: My Gr. 9 Science Fair Project: Questions
>>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
>Wouldn't parsimony suggest the same relationship between hadrosaurs and
Enough meet their fate in the jaws of crocs to make croc predation a
significant factor on mammal numbers. There are very few situations where
predation puts a population at risk of extinction, and I have not been
arguing that crocs sent hadrosaurs extinct. Rather I have been trying to
counter an argument that hadrosaurs were able to evade croc predation to an
extent that croc predation had no significant effect on hadrosaur numbers.
>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?
No, this would not be logical. But, just because hadrosaurs had deep tails
does not mean that they were good swimmers. While a deep tail can be an
effective swiming mechanism, it is unlikely that they evolved in hadrosaurs
for this purpose.
Dr Paul M.A. Willis
Consulting Vertebrate Palaeontologist
Quinkana Pty Ltd