John Harold Ostrom

John Harold Ostrom (February 18, 1928 – July 16, 2005) was an American Paleontologist who was greatly influential in the revival of scientific research on Dinosaurs. He is best known for demonstrating that Dinosaurs were less like contemporary reptiles but more closely related to large, flightless birds like the ostrich – a theory that holds its ground in the paleontological community to this day.

John Ostrom was born and raised in Schenectady, New York. His father was a physician, and John intended to study medicine at Union College, but a book would change his life. After reading The Meaning of Evolution by George Gaylord Simpson, and corresponding with Simpson himself, he decided instead to study evolution. He earned a bachelor’s degree in geology and biology by 1951, served as Simpson’s field assistant, and enrolled at Columbia University. At Columbia he studied under paleontologist Edwin H. Colbert and was offered a position as a research at the American Museum of Natural History, which he held for the next five years.

He married Nancy Grace Hartman in 1952, and together they had two daughters, Karen and Alicia. In 1955, Ostrom began teaching at Brooklyn College in New York, then the following year he taught at Beloit College in Wisconsin. In 1961, he received his doctorate in vertebrate paleontology from Columbia and was hired on at Yale as an assistant geology professor and assistant curator of vertebrate paleontology at the Peabody Museum of Natural History.

Ostrom’s first important discovery occurred in 1964, while conducting fieldwork in the Bighorn Basin of Montana. He and his assistant, Grant E. Meyer came across what appeared to be a giant fossilized claw reaching out of a mound on the slope. This claw belonged to a predatory theropod dinosaur that had lived 125 million years prior, which Ostrom named Deinoychus, meaning “terrible claw.”  He described the dinosaur as a raptor with an upright posture who would leap and slash at its prey; its muscular tail giving it counterbalance for jumping and running. He concluded that the creature had a high metabolic rate and was warm-blooded, which led to his theory that dinosaurs might share more common traits with birds and mammals than cold-blooded reptiles.

In 1970, his theory was solidified.

When on a visit to a museum at Haarlem in the Netherlands, he saw a fossil specimen misidentified as a pterosaur that had characteristics of both birds and dinosaurs. He determined that this specimen was a member of the genus Archaeopteryx, generally accepted as the earliest known bird. With this second bird-like creature identified, he began observing parallels between the Deinoychus and Archaeopteryx. In 1973, Ostrom posited that birds had, in fact, evolved from theropod dinosaurs. His discovery sparked not only his own research, but triggered what Scientific American called the “dinosaur renaissance”, a resurgence of interest in paleontology.

During his later years he gave up field work, but he continued his tenure as full professor and curator at Yale, honors he’d received in 1971.  In the early 1990s a feathered dinosaur was excavated in China that further supported his hypothesized dinosaur-bird relationship. In 1992, Ostrom retired, although he never really left Yale, continuing to research and write there until his health declined. Ostrom died at the age of 77 in Litchfield, Connecticut, from complications of Alzheimer’s disease.