Dr. Robert T. Bakker (Bob Bakker), born March 24, 1945, in Bergen County, New Jersey, is an American paleontologist who has helped re-shape modern theories about dinosaurs, particularly by adding support to the theory that some dinosaurs were homeothermic (warm-blooded). His special field is the ecological context and behavior of dinosaurs. His book The Dinosaur Heresies first propelled him to popular attention.

With a cowboy hat and his huge beard, Bakker dresses in cowboy/biker style, quite unlike the common perception of scientists. His energetic personality effectively communicates his skeptical enthusiasm for his subject, and Bakker is in demand as a talking head for dinosaur documentaries.

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. Bakker was among the advisors for the film Jurassic Park and for the 1992 PBS series, "The Dinosaurs."

At Yale, Bakker studied under John Ostrom, an early proponent of the new view of dinosaurs, and gained a PhD at Harvard. He began by teaching anatomy at Johns Hopkins University in Baltimore, Maryland. Most of his field work has been done in Wyoming, especially at Como Bluff, but he has ranged as far as Mongolia and South Africa in pursuit of dinosaur habitats.

His novel Raptor Red (ISBN 0785799729) tells the life of a female Utahraptor of the lower Cretaceous. In the story, Bakker elaborates on his theories of the behavior of dromaeosaurids ("raptor" dinosaurs) and life at the time of their existence.

The bearded paleontologist 'Dr. Robert Burke' in Steven Spielberg's film The Lost World: Jurassic Park is an affectionate caricature of Bakker. The character is eventually eaten by a Tyrannosaurus.

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