Then you see way back in human histories figures like this where people had to go hunt for their food, and of course there was danger involved in this.

让我们回到人类演化史上,如这张图所示,人们不得不去狩猎觅食,当然,这是非常危险的

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选