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Re: Horner's T. rex



>       - Predators *need* arms to catch prey.
>         T.rex arms are too small, with too limited movement to be used
>         to catch prey.

   I wonder how much more help a good set of arms would be when coupled with
an already massive, strong skull filled with meat cleavers?

>       - Fast runners have long shin bones compared to thigh bones.
>         T.rex has shin, thigh bones of equal length, so it must have
>         been a walker (conflicts somewhat with his book, where he allows
>         for the possibility of a 25 mph T.rex.)  

   But does this condition necessarily prohibit fast running?  Could it have
been an adaptation specific to T. rex to allow both fast running and legs
strong enough to fight large prey?

>       - Predators need good vision, therefore large eyes.
>         T.rex had comparatively small eyes, and small optic lobe.

   The idea that T. rex had comparitively poor vision and small optic lobes
is in contradiction to what I've heard elsewhere.

>       - T.rex had unusually large olfactory lobe; implies especially
>         acute sense of smell.  Only 2 other animals in history ever had a 
>         proportionally larger olfactory lobe:  kiwi and turkey vulture,
>         one of which is a scavenger.

   I've never liked the idea about a strong sense of smell in T. rex being
an indication of scavenging because scavenging birds have similarly strong
senses of smell.  Vultures usually are looking for very small carcasses from
very long distances, are they not?  And therefore need strong senses of
smell?  Personally, I can't see it being very difficult to smell a two ton
rotting carcass, even if the scavenger was quite a distance away.

>       - T.rex teeth are often found among mono-specific bone bed sites;
>         implies T.rex was scavenging the mass deaths in herbivore herds.

   Considering that even today hunters won't pass up a juicy carcass, this
is a weak argument at best.

>These are good arguments, but I believe there are good rebuttals to each.
>Certainly T.rex scavenged opportunistically, but I still don't buy Horner's
>scavenger-only idea.  I did challenge Jack on a couple of points:
>
>1. I asked why T.rex would need stereo vision if it only scavenged.
>   He said stereo vision is a primitive feature that T.rex just inherited,
>   although it has no need for it.

   Or, when combined with steroscopic hearing and a strong sense of smell,
could be an adaptation for picking specific individuals out of herds of tens
of thousands of animals.

>What, didn't you care for the little plastic dinos on every food plate? :-)

   Personally, I found them delicious and the best part of the meal.

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