Re: LIFE SPAN/T-REX

["Allan " <EDELS@classic.msn.com>]

I believe that some work on dinosaur life spans has been done by Dr. Anusiya 
Chinsamy  (my apologies to her if I've misspelled her name).  She based her 
impressions on her work on _Massospondylus_  (again - I haven't checked the 
spelling).  Her initial findings indicated that most dinosaurs reached the 
ripe old age of about 17 years (+/- 3).  This was on a small set of dinosaurs, 
although not limited to South Africa (as she spent several years in graduate 
studies at the Univ. of Penna. here in Phila., PA, USA).

This is not to say that the dinosaurs were not full grown - for example, dogs 
and cats have what we humans consider to be an accelerated life cycle (again I 
stress that this is from our human perspective - and our lifecycle is a bit of 
a cheat [We seem to have double the life span than our heart rate would 
indicate. Elephants live about as long as we humans do - their pulse rate is 
half of ours]).  The dinosaurs she examined were almost all full grown adults 
(as I recall).  _Massospondylus_ reached a length of nearly 30 feet.

        Still, it doesn't seem right that an animal such as T. rex or 
_Braichiosaurus_ would grow to such tremendous sizes, and do so in such a 
short time....(or last for such a short time)...

        I imagine that the truth for larger dinosaurs is that they survived 
many more 
years than the average Chinsamy comes up with.

        Greg, you're probably on the money with 40 years as the most likely top 
end 
for T. rex.  I suppose that the larger sauropods might have lived 60, 80, or 
even past 100 years.  (Of course, if the larger ones grew at the adult speed 
of 1 foot in length per year of our modern reptiles - it would take them 
120-140  years to reach the sizes that we know they reached).

        By the way, the AMNH T. rex (and the cast we have here at ANSP) seem to 
indicate that this particular T. rex was not fully grown.  (Some sutures not 
fused - check above the ankle - I've forgotten the specific term for the bone 
---- Like most things, I'll remember about 20 minutes after I've sent this 
posting).



Side note:  I saw a nest of two large ovoid eggs from Mongolia described as 
_Tarbosaurus_ eggs.  That there was only two in the nest seemed to be right.  
That's probably my old human sense of justice at work, though....  (This would 
seem to indicate that tyrannosaurids might invest a higher level of direct 
care and concern than turtles - although, not as much as portrayed in that fun 
movie).


Allan Edels