Tuesday, July 12, 2011
Ever surprised an opossum?
If so, you watched it trundle away at a leisurely pace.
When a possum beats a hasty retreat it is not a feat of swiftness, because Br'er Possum is neither built nor wired for speed.
The books that cite 7 kilometers per hour as the opossum's max don't mention that Possum probably never has to go all-out for a mile.
If overtaken by a pursuer Possum plays possum.
Collapsing, drooling profusely, evacuating bladder, colon and anal gland is no small feat of physiological multi-tasking.
The hungry predator doesn't have to fight for dinner, because dinner appears to be close to death.
Lying there with that silly grin, Possum blithely faces death with the far-off stare of a meditating yogi; indeed its respiration and heart rate decrease.
But the summation of the stimuli emanating from this hot heap of flesh is enough to make at least some predators lose their appetite.
Playing possum however is an anti-predator ploy that develops with time.
It is not in the weanling possum's bag of tricks, at least not in its full-blown manifestation.
That may explain why the little guy in the picture is missing its tail.
Whatever happened, it was lucky to get away.
Gabrielson, G. W. and E. N. Smith. 1985. Physiological responses associated with feigned death in the American opossum. Acta Physiologica Scandinavica, 123(4):393–398.