Brian Regal, a historian of science at Kean University in New Jersey, has an interesting theory about the relationship between werewolves and Bigfoot. He notes that hundreds of years ago werewolves were very prominent in popular culture. But during the past 150 years the werewolf's place in popular culture has declined, while Bigfoot has grown enormously in popularity. He attributes this shift to the theory of evolution. From Science Daily:
From the late 19th century onwards, stories of werewolf encounters tailed away significantly, says Regal. "The spread of the idea of evolution helped kill off the werewolf because a canid-human hybrid makes no sense from an evolutionary point of view," he says. "The ape-human hybrid, however, is not only evolutionarily acceptable, it is the basis of human evolution."
Contrast this with Joshua Buhs' theory, detailed in his new book Bigfoot: The Life and Times of a Legend, in which he attributes Bigfoot's popularity in the 20th century to working-class men who saw in Bigfoot "an icon of untamed masculinity, a populist rebel against scientific elites, the last champion of authentic reality against a plastic, image-driven, effeminate consumer society." (text from the Publishers Weekly review)