Dinosaurs Warm Blooded and T-Rex Lifespan

Speaking of dinosaurs here are two interesting articles. The first is about a study that claims the larger dinosaurs were warm blooded.

Research suggests the largest of the prehistoric dinosaurs had body temperatures even higher than the heat wave levels now wilting Washington.

A new study says the seven-ton, 40-foot-long, meat-eating Tyrannosaurus rex had a cruising temperature of just above 91 degrees, and the Sauroposeidon — a 90-foot-long vegetarian that weighed up to 70 tons — probably averaged a body temperature of 118 degrees.


“These findings suggest that maximum dinosaur size may have ultimately been limited by body temperature,” said lead author James F. Gillooly of the University of Florida’s zoology department.

The body temperature of dinosaurs has long been a subject of debate in biology.

For many years, scientists thought dinosaurs were coldblooded — or ectotherms — with a slow metabolism rate that required the sun’s heat to regulate their temperature.

But starting in the late 1960s, some began promoting the idea that the beasts may have been endotherms — warmblooded creatures, much like mammals and birds — with relatively constant high body temperatures that were internally regulated.

I believe one of the first to suggest that some dinosaurs were warm blooded was Bob Bakker.

Bakker has been a major proponent of the theory that dinosaurs were “warm-blooded,” smart, fast, and adaptable. He published his first paper on dinosaur endothermy in 1968. He revealed the first evidence of parental care at nesting sites for Allosaurus.

And here is something I didn’t know about Dr. Bakker,

In addition to being a scientist, Bakker is also a Pentecostal preacher who is a strong proponent of theistic evolution.

The second article is about the life span of the Tyrannosaurid Albertosaurus.

One species of tyrannosaur lived to be about 30 years old, a life span that more closely resembles a large present-day mammal than a reptile, researchers said.

The researchers studied the metatarsals, or foot bones, of 22 Albertosauruses, a species of the feared carnivore, excavated from a single site in Alberta, Canada, one of the world’s largest sources of dinosaur remains. The authors were able to use the bones to determine the life span of the dinosaurs, the researchers said.

“There is a lot of potential for this kind of research to understand these animals, not just as representatives of their species, but as parts of populations,” said Gregory Erickson, professor of biology at Florida State University and coauthor of the study in tomorrow’s edition of the journal Science.

The researchers found that mortality rates for Albertosaurus were high in the first two years of life, possibly due to predation, and then decreased until the teenage years, according to the researchers.

After age 13, the mortality rates jumped to 23 percent, researchers found. Dinosaurs lived roughly 30 years, about the same length of time as bears. Some reptiles can live 50 to 100 years or more.


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Steve Verdon
About Steve Verdon
Steve has a B.A. in Economics from the University of California, Los Angeles and attended graduate school at The George Washington University, leaving school shortly before staring work on his dissertation when his first child was born. He works in the energy industry and prior to that worked at the Bureau of Labor Statistics in the Division of Price Index and Number Research. He joined the staff at OTB in November 2004.


  1. floyd says:

    we now know what happened to the proto-human scientists who thought that t-rex was not only warm, but cuddly.