Bigfoot was a common nickname for unusually large, aggressive grizzly bears who ate cattle, sheep and attacked people.

• In 1958, a California tractor operator found a series of huge muddy footprints.
• In 1976, naturalist Ivan T. Sanderson published a book where he used footprints, eyewitnesses, and bone samples as potential evidence of "sub-humans" living of five continents, including North America's Sasquatch and the Himalayas' Yeti.
• In 1982, Sanderson's book was followed by the Patterson-Gimlin film. The film became a phenomenon.

Grover Krantz, a professor of physical anthropology at Washington State University also believed in Sasquatch. He was ridiculed for his conviction.

During and after his death, the search for Bigfoot took on a life of its own. More sightings, films, and books emerged. Documentaries captured the public's imagination. However, there is a lack of evidence. Without a body (or skeleton), it's hard to convince others.