For next steps, do a Google search of gigantopithecus blacki (a 10-foot tall ape) and the giant short-faced bears of the Arctodus family, which also grew up to about 10 feet tall.

Then, about 40,000 to 65,000 years ago, most of these large animal species went extinct, including all of the short-faced kangaroos and some of the long-faced kangaroos. And the question is — why?

This alone dispels the notion that all short-faced kangaroos were driven extinct as a direct result of a restricted diet.

Then, about 40,000 to 65,000 years ago, most of these large animal species went extinct, including all of the short-faced kangaroos and some of the long-faced kangaroos.