Bolson tortoises, some weighing more than 100 pounds, once grazed parts of the southwestern U.S. before disappearing around 10,000 years ago, victims of human hunting.

• 有些墨西哥象龟重达45公斤，曾在美国西南部吃草生活，后来约在一万年前消失无踪，是人类狩猎的牺牲品。