August 6, 2009

T-rex’s diet may have been young dinosaurs

The fearsome Tyrannosaurus rex may not have feasted on feisty adult game, but eyed smaller, more docile prey at chow time, German researchers reported.

T-rex fossils indicate the large predatory dinosaurs preyed on juvenile dinosaurs, researchers at Ludwig-Maximilians-Universitat in Munich reported Thursday in a news release.

Unlike their adult and well-armed relatives these young animals hardly posed any risk to the predators, Oliver Rauhut said. And their tender bones would have added important minerals to a theropod's diet. Now we hope for more fossils to be found that add new evidence to our hypothesis.

Animals such as the Tyrannosaurus rex often are viewed as the perfect killing machine with strong bites capable of bringing down huge prey, Rauhut said.

But the very few fossils that reflect the hunt of predatory dinosaurs on large herbivores tell a tale of failure -- the prey either got away, or both prey and predator were killed, he said.

However, direct evidence, such as stomach contents, that T-rex preyed on the young is hard to come by as well, the researcher said.

Rauhut and his partner, David Hone, with the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, hypothesize that large predatory dinosaurs attacked other large dinosaurs only as an exception, feeding mainly on juveniles.

Even modern predators prefer old and sick animals or inexperienced young individuals, Hone said. These are an easy prey to bring down and the risk of injury for the predator is much lower. This strategy was probably the same in dinosaurs.