T Rex

Why did some dinosaurs grow so big?

Paleontologists don't know for certain, but perhaps a large body size protected them from most predators, helped to regulate internal body temperature, or let them reach new sources of food (some probably browsed treetops, as giraffes do today). No modern animals except whales are even close in size to the largest dinosaurs; therefore, paleontologists think that the dinosaurs' world was much different from the world today and that climate and food supplies must have been favorable for reaching great size.

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This page is URL:https://pubs.usgs.gov/gip/dinosaurs/growth.html
For more information, please contact Robert Weems at rweems@usgs.gov or Ronald Litwin at rlitwin@usgs.gov.

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Last modified 05-17-01 (krw)