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Did T-Rex face midlife crisis?

By ASSOCIATED PRESS
Published July 14, 2006


WASHINGTON - Even the powerful tyrannosaurs seem to have encountered a midlife crisis.

Once they made it to about age 2 they could take on just about any other predator and had very little mortality until they reached sexual maturity in their teens, researchers report in the journal Science.

"Survivorship stabilized at between 2 and 4 percent per year until midlife at which point they went through an honest-to-God midlife crisis," said Gregory M. Erickson of Florida State University.

His team studied the remains of several species of North American tyrannosaur, and calculated the mortality rates for the animals. They concluded mortality could be high for youngsters, both because of disease and because of predators.

But after about age 2, some 70 percent survived to reach sexual maturity between 13 and 16, when mortality increased to 23 percent.

"I think love was a dangerous game for tyrannosaurs," said Erickson.

It's a life pattern - high mortality young and then stability until midlife - also seen in some modern birds and mammals, he said.

[Last modified July 14, 2006, 02:51:29]


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