Grover Sanders Krantz (November 5, 1931 – February 14, 2002) was an American anthropologist and cryptozoologist; he was one of few scientists not only to research Bigfoot, but also to express his belief in the animal's existence.

[10] In the early 1960s, Krantz worked as a technician at the Phoebe A. Hearst Museum of Anthropology in Berkeley, California before acquiring a full-time teaching position at Washington State University, where he taught from 1968 until his retirement in 1998.

[3][4][6] He was a popular professor despite giving notoriously difficult exams, and often ate lunch with students and talked about anthropology, unified field theory in physics, military history, and current events.

[12] He also wrote an influential paper on the emergence of humans in prehistoric Europe and the development of Indo-European languages, and was the first researcher to explain the function of the mastoid process.

[1] His professional work was diverse, including research on the development of Paleolithic stone tools, Neanderthal taxonomy and culture, the Quaternary extinction event, sea level changes,[4] and the evidence of sex in the human fossil record.

[10] Krantz's specialty as an anthropologist included all aspects of human evolution, but he was best known outside of academia as the first serious researcher to devote his professional energies to the scientific study of Bigfoot, beginning in 1963.

[10] Because his cryptozoology research was ignored by mainstream scientists, despite his academic credentials, in a bid to find an audience Krantz published numerous books aimed at casual readers and also frequently appeared in television documentaries, including Arthur C. Clarke's Mysterious World, In Search of..., and Sasquatch: Legend Meets Science.

[10] Krantz's studies of Bigfoot, which he called "Sasquatch," (an Anglicization of the Halkomelem word sásq’ets (IPA: [ˈsæsqʼəts], meaning "wild man")[15] led him to believe that this was an actual creature.

He theorized that sightings were due to small pockets of surviving gigantopithecines, with the progenitor population having migrated across the Bering land bridge, which was later used by humans to enter North America.

"[8] After years of skepticism, Krantz finally became convinced of Bigfoot's existence after analyzing the "Cripplefoot" plaster casts gathered at Bossburg, Washington in December 1969.

Krantz later studied the Patterson–Gimlin film in full, and after taking notice of the creature's peculiar gait and purported anatomical features, such as flexing leg muscles, he changed his mind and became an advocate of its authenticity.

The Cripplefoot tracks, left in snow, purportedly showed microscopic dermal ridges (fingerprints) and injuries tentatively identified as clubfoot by primatologist John Napier.

[10] After constructing biomechanical models of the Cripplefoot casts by calculating their distance, leverage, weight dynamics and distribution, and comparing the data to the track's heel, ankle and toe base, Krantz concluded that the footprints had been left by an animal about 2.44 m (8 ft) tall and weighing roughly 363 kg (800 lb).