This is just gross enough to interest a 5th grader (boy):
When a hognose snake that's facing a predator flips belly-up, its mouth opens and stays agape, sometimes oozing drops of blood. And the snake defecates or otherwise releases an unappetizing smell. "It's spectacular," says Gordon Burghardt of the University of Tennessee in Knoxville. [More great stuff]
While I was closing up bins and cleaning up scattered tools, etc. our silly dog encountered a young possum, which promptly "died" and sure enough, the dog lost interest. I've always wondered how effective this strategy was.
Playing dead can be a clever ruse as well:
One break came after he'd floated for 15 minutes staring at a dead-looking Parachromis friedrichsthalii cichlid. Smaller fish gradually drew closer until some began nibbling the cichlid's tattered fins. In an instant, the seemingly dead fish reared off the bottom and attacked one of the scavengers.
Although this cichlid is a death feigner, it's not trying to avoid predators, Tobler said in the March 2005 Journal of Fish Biology. It is itself a predator, and feigning death is the way that it hunts.
Given the number of possums I see around here, feigning death must work.
Pretty darn well.