Portal was the first Valve-developed game to be added to the OS X-compatible list of games available on the launch of the Steam client for Mac on May 12, 2010, supporting Steam Play, in which players that had bought the game either on a Macintosh or Windows computer could also play it on the alternate system.
1 Eurasian Pleistocene megafauna became extinct in roughly same time period despite having a much longer time to adapt to hunting pressure by humans. 2  However, the extinction of the Eurasian megafauna can be viewed as a result of a different process than that of the American megafauna.
edit Period on Earth. The mammoth lived from the Pliocene epoch, about two million years ago, into the Holocene age. Most mammoths became extinct 10,000 years ago. Some smaller woolly mammoths, one of the species of mammoths, lived on an isolated island until 3750 BC. The mastodon pre-dated the mammoth, although there was overlap. Mastodons lived from the late Miocine era, about 5.3 million years ago to the late Pleistocene era, which ended 10,000 years ago. Mastodons became extinct 10,000 years ago. The precise reason why both species became extinct is unknown.