Why Some Animals Play Dead

A number of animals including mammals, insects, and reptiles exhibit a type of adaptive behavior known as playing dead or tonic immobility. This behavior is commonly seen in animals that are lower on the food chain but can be exhibited in higher species. When faced with a threatening situation, an animal may appear lifeless and may even emit odors that resemble the smell of decaying flesh. Also known as thanatosis, playing dead is often used as a defense mechanism, a trick to catch prey, or a means to sexually reproduce.

Snake in the Grass

Eastern Hognose Snake Playing Dead. Ed Reschke/Getty Images

Snakes sometimes pretend to be dead when they sense danger. The eastern hognose snake resorts to playing dead when other defensive displays, such as hissing and puffing up the skin around their head and neck doesn't work. These snakes turn belly up with their mouths open and their tongues hanging out. They also emit a foul-smelling liquid from their glands that deters predators.

Playing Dead as a Defense Mechanism

Virginia Opossum Plays Dead. Joe McDonald/Corbis Documentary/Getty Images

Certain animals play dead as a defense against predators. Entering into a motionless, catatonic state often dissuades predators as their instinct to kill drives their feeding behavior. Since most predators avoid dead or rotting animals, displaying thanatosis in addition to producing foul odors is enough to keep predators at bay.

Playing Possum

The animal most commonly associated with playing dead is the opossum. In fact, the act of playing dead is sometimes referred to as "playing possum". When under a threat, opossums can go into shock. Their heart rate and breathing is reduced as they fall unconscious and become stiff. By all appearances they seem dead. Opossums even excrete a liquid from their anal gland that mimics odors associated with death. Opossums can remain in this state for as long as four hours.

Fowl Play

A number of different bird species play dead when under threat. They wait until the threatening animal has lost interest or is not paying attention and then they spring to life and make their escape. This behavior has been observed in quail, blue jays, different species of ducks, and hens.

Ants, Beetles and Spiders

When under attack, young fire ant workers of the species Solenopsis invicta play dead. These ants are defenseless, unable to fight or flee. Ants that are just a few days-old play dead, while ants that are a few weeks-old flee, and those that are a few months-old stay and fight.

Some beetles pretend to be dead when they encounter predators such as jumping spiders. The longer the beetles are able to feign death, the greater their chances for survival.

Some spiders pretend to be dead when facing a predator. House spiders, harvestmen (daddy longlegs) spiders, huntsman spider, and black widow spiders are known to play dead when they feel threatened.

Animals That Mimic Leaves

By Regina Bailey

Playing Dead to Avoid Sexual Cannibalism

Praying Mantis — Mantis religiosa, with the common name praying mantis or European mantis, is an insect in the family Mantidae. fhm/Moment/Getty Images

Sexual cannibalism is common in the insect world. This is a phenomenon in which one partner, typically the female, eats the other before or after mating. Praying mantis males for example, become motionless after mating to avoid being eaten by their female partner.

Sexual cannibalism among spiders is also common. Male nursery web spiders present an insect to their potential mate in the hopes that she will be amenable to mating. If the female starts to feed, the male will resume the mating process. If she does not, the male will pretend to drop dead. Should the female start to feed on the insect, the male will revive himself and continue to mate with the female.

This behavior is also seen in the Pisaura mirabilis spider. The male offers the female a gift during a courtship display and copulates with the female while she is eating. Should she turn her attention to the male during the process, the male feigns death. This adaptive behavior increases the males chances of copulating with the female.

Playing Dead to Catch Prey

pselaphid beetle (Claviger testaceus) — Claviger testaceus, specimen held in the Oxford University Museum of Natural History. Joseph Parker/Wikimedia Commons/CC BY-SA 3.0

Animals also use thanatosis in order to trick prey. Livingstoni cichlid fish are also called "sleeper fish" for their predatory behavior of pretending to be dead in order to catch prey. These fish will lie down at the bottom of their habitat and wait for a smaller fish to approach. When in range, the "sleeper fish" attacks and consumes the unsuspecting prey.

Some species of pselaphid beetles (Claviger testaceus) also use thanatosis to get a meal. These beetles pretend to be dead and are carried away by ants to their ant nest. Once inside, the beetle springs to life and feeds on the ant larvae.

_Sources:

_{Springer. "Playing Dead Works For Young Fire Ants Under Attack." ScienceDaily. ScienceDaily, 10 April 2008. http://www.sciencedaily.com/releases/2008/04/080408100536.htm.}
_{Map of Life - "Thanatosis (feigning death) in spiders and insects". August 26, 2015. http://www.mapoflife.org/topics/topic_368_Thanatosis-(feigning-death)-in-spiders-and-insects/}