Page 90 - 2006 DT 12 Issues

Playing Possum shelf to hold his surgical tools while ing he’d killed it, he dropped it in the
he cut the hook out of its mouth. Once grass. The shamming snake remained

hysiological ecologist Gary back in the water, the shark revived immobile, never flipping back to its
Gerald of Miami University in and swam away. original position.
POxford, Ohio, was observing Other examples of “extreme im- These various behaviors leave a lot
some newborn brown snakes crawling mobility” under various circumstances of questions unanswered. How much
on a lab table. When he dropped them abound, but researchers are now less of it is intentional, how much is re-
into a water filled gutter, they flipped willing to label them instances of flexive, how much represents a shock
on their backs and went rigid, remain- feigned death or make claims about reaction? Are the feigners conscious
ing motionless. He concluded that such behavior’s function. Sometimes, of the watchers?
this was another example of animals however, an animal will go to rather Insects have become the subject
feigning death. elaborate extremes. of similar study. Japanese research
Lots of animals “play possum.” In cock fights, a chicken will oc- on sweet potato weevils and red flour
The first noted instance of the so called casionally roll over “dead,” but then beetles suggests that death feigning
behavior is credited to the Virginia “miraculously” revive once the owner behavior is a survival strategy that
opossum, which “plays dead” when picks it up. A hognose snake facing a seems to work. Yet a curious behav-
threatened. Actually, it isn’t playing ior by a pygmy grasshopper was only
at all. The poor critter goes into shock observed when the insect was taken
when stressed and rolls over on its side by a frog rather than any other preda-
with its legs extended, limp as a rag tors. Once in the frog’s mouth, the
doll. Nevertheless, it works. grasshopper bent its legs straight down
Conventional wisdom maintains and went rigid. Frogs are the only
that predators lose interest in their grasshopper predators that swallow
prey when it doesn’t move, but re- their prey whole. In the lab, of 20 intact
cent observations are challenging grasshoppers fed to a frog, 16 of them
that theory. eventually escaped to hop again. The
According to Gerald, there are at posture merely made the grasshoppers
least 21 species of snake and many hard to swallow.
other disparate creatures that feign Playing possum is not just for prey.
death, such as bison and brittle stars. When fish biologist Michael Tobler
But for many others, similar behavior of the University of Oklahoma went
may or may not be play acting. snorkeling in the Yucatan, he saw a
For some animals, such as rab- dead looking cichlid fish lying on the
bits and chickens, being flipped on predator will flip belly-up, its mouth bottom of a cenote sinkhole two days
their backs induces a freeze. Marine agape, perhaps oozing drops of blood. in a row. Several days later, he saw the
biologist John Morrissey of Hofstra Then it defecates or releases a foul seemingly dead fish draw a number of
University in Hempstead, N.Y. tells smell. Not a bad act. But when a re- smaller fish that began to nibble on its
of accidentally hooking a 14-foot tiger searcher came upon a death-feigning tattered fins. An instant later, the cich-
shark while fishing for lemon shark in lid came to life and attacked one of the
the Caribbean. While trying to save it hognose in the woods, he flipped it scavengers, a behavior only observed
and dislodge the hook from the shark’s back on its stomach only to have the twice before.
mouth, he and his companions flipped snake flip back into the death pose Playing possum has come to sug-
the wildly thrashing shark on its back. again—not too convincing. Grass gest a whole range of behaviors—some
The shark immediately became “as snakes make no such mistake. When a deliberate, some unintentional. Mother
hypnotized as a chicken.” Morrissey researcher in British Columbia caught Nature is nothing if not clever. She has
used the tranquil shark’s stomach as a one, it immediately went limp. Think- many tricks we have yet to learn. ❏

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