【英语时差8,16】为何负鼠倒挂于树（下）（在线收听）

Like kangaroos, ‘possums are marsupials, and the females carry and nurse their young in pouches on their abdomens. The opossum, Didelphis virginiana, is the only marsupial native to North America. Playing ‘Possum These solitary, nomadic omnivores are also known for their unusual defense mechanism. When threatened, they often enter a comatose like state, becoming rigid and unresponsive. They appear to be dead and even release a malodorous substance from their anal glands that makes them smell dead. This behavior is often called “playing ‘possum,” but the response is an involuntary physiological reaction rather than a conscious act or trick. ‘Possums may remain in this state from a few minutes to 4 hours. Often looked upon with disdain or disgust, this misunderstood marsupial is actually one of North America’s most unique and harmless mammals.