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Re: crocs and hadrosaurs (was science proect)



Betty wrote:

>  Actually crocs near the shore would more likely be spotted by the taller
> T rex as they lose their camoflage abilities when viewed from above (like
> in croc pits at zoos), so the crocs would probably be leary of coming
> within reach of a taller advisary.  This would seem to also work against
> the crocs and for duckbills-except with the newer quadrepedal posture of
> duckbills (and not the old bipedal one) their heads would be much closer
> to the ground, especially while feeding, than T rex's and so the crocs
> could still depend on camouflage for stealth.

I figured a running duckbill would be on two legs if only to keep its
bill from bumping the ground.  I figured the duckbill wouldn't see the
croc, but if it happened to be headed straight for the croc, the croc
would back away until he could see the situation.  

Anyway, it seems unlikely that the duckbill would run right into the
croc's jaws.  If the duckbill didn't run into the croc, wouldn't the
duckbill survive if it was a good enough swimmer to tire the croc before
the croc could close the distance?

> Maiasaurs nested on lakeshores-not strictly a swamp, but pretty similar
> conditions. Sort of like how modern flamingoes and storks nest in the
> mudflats of the African savannahs after the rains.  Both of these can fly
> to protect the adults, but they rely on the water to isolate and protect
> the young.

I wonder if there were crocs along the lakeshores.  Unless duckbills
could nest where predators couldn't reach, they must have had a way to
stand their ground against whatever predators were present.  

> >Don't crows drive hawks and owls from an area by harassment?  Couldn't
> >duckbills  also have used commotion and tooting to encourage big crocs
> >to relocate?
> 
> probably not crocs- modern types hunt by camouflaging themselves and
> waiting for prey to come by.  In all likely hood, it's only the first
> duckbill which would be taken unawares, and the rest of the herd would be
> alerted by the struggle.  Since the croc kills by strangulation and
> drowning, the duckbill may not be able to honk at all-no matter how big
> it's crest is. (or conversly-maybe that's what the dang things are
> for-doesn't seem likely since there would be no muscle forcing the air
> out)

Yeah, I wonder about the lack of an acoustic coupler, like the bell of a
trumpet or the mouth of a mammal.  It seems as if a duckbill toot would
be only as loud as someone humming.  I'm glad Della is checking into
it.  One experiment is worth a thousand books!

I figured my crow-like duckbills would raise a fuss before the croc
struck.  When I was a teen, my uncle invited me to shoot crows who were
eating his corn.  They weren't afraid of people.  I found that things
were different when I was carrying a gun, even inconspicuously. 
Somehow, their sentry knew from a long way off.  Then, no matter what I
did to get within range of the crows of the ground, he always knew where
I was.  

I've read that if several men enter a blind individually over a period
of time and leave over a period of time, crows will know it's occupied
until the last man leaves.  Animals with similar mental capacity could
be good at keeping track of the last known location of a croc and the
locations where it might now be.

Our Dobermans used barking and sometimes nips to keep predators away  . 
Subsequent dogs were less effective.  We started finding stray dogs,
possums, coons, foxes, and egg-sucking snakes.  

If a giant croc came up the creek, I think those Dobermans would have
harassed it with barking and feints until it left.  After all, how could
the croc live that way?  Crows seem to use that technique to chase away
birds of prey.  

>People are just plain ol' dumb to kill a snake-means they were 
>raised wrong

Hens who are out scratching will attack kittens and puppies even if the
mammals are minding their own business and the puppies are bigger than
the hens.  It would have taken many years for a croc to grow big enough
to endanger adult duckbills, but it would have been a threat to duckbill
offspring.  

If duckbills were endotherms, I think they would have had opportunities
to stamp on sluggish crocs who had come ashore to warm up.

Thanks for your remarks.

- Stephen