Opossum

Opossum, originally uploaded by Hannibals Animals.

The Virginia Opossum (Didelphis virginiana), commonly known as the North American Opossum, is the only marsupial found in North America north of the Rio Grande.
The Virginia Opossum is noted for its reaction to threats, which is to feign death. This is the genesis of the term "playing possum", which is used to describe an attempt to pretend to be dead or injured with intent to deceive. In the case of the opossum, the reaction seems to be quite involuntary, and to be triggered by extreme fear. It should not be taken as an indication of docility, for under serious threat, an opossum will respond ferociously, hissing, screeching, and showing its teeth. But with enough stimulation, the opossum will enter a near coma, which can last up to four hours. It lies on its side, mouth and eyes open, tongue hanging out, emitting both a green fluid from its anus and an odor putrid to most predators. Besides discouraging animals who eat live prey, playing possum also convinces some large animals that the opossum is no threat to their young.