Influential Paleontologist John Ostrom, 77, Dies

Enlarge Bill Sacco

Dr. John Ostrom, pictured with a recreation of the Deinonychus skeleton suspended behind him.

Bill Sacco

Dr. John Ostrom, pictured with a recreation of the Deinonychus skeleton suspended behind him.

Enlarge Corbis

A Deinonychus model and skeleton. Ostrom's 1964 discovery of Deinonychus in Montana prompted him to conclude that dinosaurs were warm-blooded, and were the logical ancestors of birds.

Corbis

A Deinonychus model and skeleton. Ostrom's 1964 discovery of Deinonychus in Montana prompted him to conclude that dinosaurs were warm-blooded, and were the logical ancestors of birds.

Dr. John Ostrom, a Yale University paleontologist who pursued the idea that birds descended from dinosaurs, helping to revolutionize our thinking about the extinct creatures, has died. He was 77.

Ostrom died last Saturday of complications from Alzheimer's disease at an assisted living center in Litchfield, Conn.

He was best known for his 1964 discovery of Deinonychus, a small two-legged carnivorous dinosaur whose name means “terrible claw." In 1969, Ostrom published a controversial theory that Deinonychus was a warm-blooded creature, contradicting the belief, widely held by scientists at the time, that dinosaurs were cold-blooded.

Ostrom was also known for pursuing the idea, first advanced in the 19th century, that Deinonychus and other bipedal theropod dinosaurs (a group that includes Tyrannosaurus rex and Velociraptor) are the ancestors of all birds.

Ostrom first advanced this theory in the 1970s, to the derision of fellow paleontologists. But numerous feathered dinosaur fossils discovered in China over the last decade have helped validate Ostrom's findings.

NPR's Robert Siegel discusses Ostrom's life and legacy with Dr. Robert Bakker, director of the Morrison Natural History Museum in Morrison, Colo. Bakker was Ostrom's student research assistant and was with him in Montana when he first discovered Deinonychus.