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Posted on 07/14/2006 2:11:38 PM PDT by Al Simmons
Youth was easy for big predatory dinosaurs – but adulthood and old age much harder to survive, a mass graveyard of tyrannosaur fossils suggests.
This first study of dinosaur population distributions shows that most juvenile tyrannosaurs survived to reach sexual maturity, but then their death rate increased sharply in adulthood. This life-pattern is similar to those of long-lived birds and mammals.
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Biologists study population distributions of modern animals by counting individuals and keeping track of deaths. This is not possible for extinct creatures, and fossilised remains are also scant for many dinosaurs. But Erickson turned to the tyrannosaur family that roamed North America from about 80 to 65 million years ago, late in the Cretaceous period, which left abundant fossils.
His team studied a bone bed in Alberta, Canada, containing the bones of at least 22 Albertosaurus individuals which died during an unusually harsh period. They range in length from 2.2 metres to 10.1 m. By counting annual growth rings in the bones and measuring sizes of the femurs, Erickson's group estimated the ages at which the 22 animals died.
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The youngest animal was about two years old and 2.2 m long. About two-thirds of the animals had made it to age 13 or beyond, indicating that only 2% to 7% of juveniles died each year before reaching sexual maturity, at about 14.
But after that the death rate jumped to an average of 23% each year between the ages 14 and 23, and the oldest Albertosaurus died aged 28.
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(Excerpt) Read more at newscientist.com ...
7-feet of teeth, at two years old. Uh, honey, where is the pacifier, again?
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lol! wherever kels spit it out.
smart girl hated those things,
unlike her brothers ;)
smart girls in my family. ;)
Old age is inevitably fatal if nothing else gets you first.
Great article. Thanks for posting it. When I first saw the headline, I thought it was going to be another article where people reinterpreted history to suit their personal sociological perspectives. They seem to have good evidence for their claims, and speak in slightly guarded terms, indicating they're open to new interpretations if the evidence suggests.
Were these purchased thru Albertsons?
Were these purchased thru Albertsons?
Is that where Fred Flintstone shopped 6000 years ago? These could be the remains of a one of Fred's Famous holiday BBQs.
LOL!
They found Helen Thomas ?
Ping
What is this ping list you've got me on?
"adulthood and old age much harder to survive"
Didnt know it was possible to survive old age or adulthood, even for humans.
I like the part about the hideous bites found on the faces of adults. How hot would a female Tyrannosaur have to be for a young suitor to risk getting his face removed? I think I'd just opt for Tyrannosaur Monkdom.
Let me know if you want off of it....
Yes, please take me off. I've already got all the crevo I can handle.
No sooner said than done....
Ask a Praying Mantis.....
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