Playing Possum

Playing possum is something that Virginia opossums do, but so do some other animals—including humans. But because it can help animals to outsmart a threatening predator, can it save us from a terrorist shooter or a rapist or a grizzly attack? A few plucky people have credited their survival through mass shootings in America and Europe to acting dead.

When the Scottish explorer David Livingstone was attacked by an African lion he tumbled into a delirious, catatonic state that bore a resemblance to death. “(The lion) caught me by the shoulder as he sprang, and we both came to the ground together. Growling horribly close to my ear, [the lion] shook me as a terrier dog does a rat. The shock . . . caused a dreaminess, in which there was no sense of pain nor feeling of terror, though quite conscious of all that was happening.” He survived the ordeal, not because the big cat turned its nose up at Livingstone’s “dead meat,” but after a native teacher came to his rescue.Poem_possum

I was musing about this story after I rescued a toad from our pool. It was a spadefoot toad (Scaphiopus holbrookii), so-called because it has a black, horny spur on each hind leg for digging holes. We rarely see this species because it lives most of the year underground and only ventures out in warm, wet weather.

When I saw it floating with outstretched limbs I guessed it was alive, but after netting it and holding it in my palm it was curled up as if it was dead. Motionless and unresponsive, its eyes were half-closed and both pairs of limbs were gathered in a praying attitude (for a toad). It didn’t fool me, but the attempt might be beguiling to someone who wanted to eat it. So I set it down on a rock beside the frog pond and stood back to watch. Two minutes later an eye cracked open, then a limb extended tentatively, and next it had disappeared into the pond with a fruity “plop.”

spadefoot toad plays possum

spadefoot toad plays possum

I can’t find any reference to spadefoot toads playing dead (scientifically called thanatopsis/ thanatosis), although it has been observed in other amphibians and when I cast a wider search I found examples in a range of animals. Some, like the toad, simply look moribund when threatened, but the hog-nosed snake goes further by emitting a foul odor to repel predators from taking “old meat.” There are sharks, iguanas, fire-bellied toads, cichlid fish, and even spiders that play dead, although in the last case only among males courting a much larger female. Even rabbits will sometimes act this way, although this might surprise people who grew up on a diet of heroic stories about Hazel and Bigwig (Watership Down by Richard Adams). Orcas have no predators so when they are acting dead they hope to trick their prey.

Scaphiopus holbrookii

Back from the dead

It must have taken many generations for these behaviors in toads and other prey species to replace the more natural instinct to fight or run or hide. Evolution comes at a high price of mortality until the hunted have perfected their act for fooling the hunter. But what should people do? Apart from those who play dead as art noir, it’s probably not wise in real life, and the security services don’t recommend we try when in dire straits.

Next Post: Where the Bee Stings

 

About Roger Gosden

British-born scientist specializing in human and animal reproduction & embryology. Academic career spanned from Cambridge and Edinburgh to McGill and Cornell's Weill Medical College in Manhattan where he was Professor & Research Director. Married to Lucinda Veeck Gosden, embryologist for the first successful IVF team in America, he retired early to Williamsburg, Virginia, to write and to recover from 'nature deficit disorder'
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