The most widely known fact about a certain American animal is that he pretends to be dead when an enemy catches him. Playing possum, it is called. To see that play for the first time is to be amazed, as if witnessing an incredible comedy of the wild. Yet the habit of shamming is as widespread as animal life, being especially prevalent among the lower orders. Disturb a praying mantis at his fly catching, and the grotesque creature pretends to be a dead twig; or catch a ladybird (lady beetle, ladybug) when she is helping you raise roses by eating the aphids or plant lice, and the pretty little thing turns up her toes in your hand. "Insects are most notorious in this respect," said Charles Darwin, who concluded in his Essay on Instinct, published in the appendix of George J. Romanes' Mental Evolution in Animals, that some creatures feign death for a moment only, and others so persistently that they make no response even to a fire that kills them.
Shamming takes a more appealing form when you come suddenly upon a brood of young quail or young grouse. While the mother pretends to be hurt, floundering at your feet to hold your attention, the chicks promptly play dead, one chick half hidden under a brown leaf, another flat on its back with stiffened legs, a third propped against a stump and looking like a shred of bark.
That this habit of young grouse survives to old age was proved to my satisfaction one early morning in the Maine woods. I was sitting on a log, waiting for a bull moose that had shyly answered my call at twilight, when a gorgeous cock partridge came down the trail and hopped up on a log beside me—only one of many indications that wild eyes rarely notice a motionless figure. He started mincing along the log, stepping daintily, his back turned, when, in idle curiosity, I caught him, holding his wings close against his sides. On the instant he collapsed and lay in my hands like a dead bird. Even the eyes half open and very moist, as if teary, were those of a partridge shot down in swift flight. I was stroking the beautiful plumage, regretting my hasty experiment, when he flipped out of my relaxed grip and whirled away into a spruce tree. He had played possum to good effect, certainly. But did he know what he was doing, and why?
One difficulty of answering our question is that birds are easily subject to hypnosis, or something akin to it, as you may prove by shining a looking glass into a chicken's eyes, or rubbing its beak to and fro along a crack of the barn floor, after which it apparently cannot move. Sportsmen who conduct amateur field trials have lately learned what almost any country boy could have told them—that if you swing a pheasant dizzily in the air it will stay wherever you set it down, thus permitting the oncoming dogs to point it.
The probable explanation is that birds have a very delicate sense of balance, else they could hardly fly, and to upset the nervous balance is to inhibit the will and to put muscles out of action. Unless the wings are held fast during the swinging they will react automatically in order to keep the balance, and the pheasant will run or fly the moment its feet touch the ground. It is therefore possible that my cock partridge did not know what he was doing, being stupefied by a sudden powerful grip.
Among the higher orders of animal life the possum is the best of pretenders, not only because he feigns death habitually but more because most possums do it in the same way, as if obedient to a fixed behavior pattern. If so, his shamming is purely instinctive, with no plan or purpose or intelligence about it. Professor William Preyer reached this conclusion after a long series of experiments. A powerful emotion of fear, he said, paralyzes the nerve centers and puts the animal into a state of catalepsy. He is not pretending to be dead but is frightened into a deathlike stupor.
SILENT UNTO DEATH
I came to this same conclusion on seeing my first horned owl swoop on a possum, only to swerve aside when his wing touched a bush. The possum played dead before he was touched, and held the pose until the owl swooped again. So far as human eyes could see, he made no struggle, no resistance, even when the savage bird began to tear his body to pieces.
In the autumn of that same year (1939) an uncommonly large possum was caught at a game farm, in Redding, Conn. He was moving aimlessly around the wire trap when I pulled him out by the neck, and to all rib poking or hair pulling he made no more response than a dead possum. Not till I set him on the ground and began to back away did his eyes open, and my impression was that they watched. Slowly the distance increased to a dozen feet, when the possum rolled over and headed away, but not hurriedly. When caught by the neck he again played dead, refusing to respond when I twisted the ratty tail. So I carried him to a nearby brook and dropped him in. At the touch of cold water he came to life and floundered away from me to the other bank, which might imply that he was both conscious and intelligent when he played dead.
When chased by hounds, possums vary their action according to circumstance. If caught on the ground they play dead and—an odd fact which may be illuminating—the hounds are usually disgusted and turn away, though they will shake the life out of a moving possum. If near a tree when the hounds approach, the possum climbs to the lowest branch, where he turns to wrinkle his piggy nose and hiss at his impotent enemies. This again appears to be a case of intelligence rather than of blind instinct.