Startling a Predator

Startling a Predator
Anyone who has jumped when startled knows how a predator might feel when its prey suddenly bursts into motion after being nearly invisible. The shock of the prey’s sudden reappearance is enough to make a predator flinch or pause for a fraction of a second. That little bit of extra time can let an animal escape with its life.

A variety of animals even sport special colors or body parts to help them startle predators. These colors and parts are used in behaviors called startle displays. A startle display may be used to fend off an attack right from the start. Many startle displays of this type involve suddenly flashing a vivid color or pattern.

This is the tactic used by the io moth, which lives in North America. At rest, an io moth is pale yellow or brown. But if a bird attempts to grab it, the io moth quickly moves its forewings. This reveals two hind wings boldly colored with a pair of big black spots surrounded by a circle of yellow. These spots look like eyes, and are called eyespots. To a bird, the display of eyespots may look like the sudden appearance of a larger bird, such as an owl— its own predator. The startled bird may fly away rather than risk its life, or it may pause long enough for the moth to escape.

Eyespots are found on the wings of hundreds of species of moths and butterflies. They are also seen on many caterpillars. A swallowtail butterfly’s plump green body has two huge yellow eyespots on its humped front end. This makes it look like a snake. When threatened, the vine hawk moth’s brown caterpillar curls into a “C” and bulges its yellow eyespots. A Malaysian hawk moth caterpillar puffs up its front end when threatened. This makes its eyespots open wide. It also snaps its head back and forth as if it were a snake about to strike.

Other insects flash startling eyespots, too. The African flower mantis, which usually blends in with the shapes and colors of its flowery habitat, flares out wings with eyespots when it is threatened. The eyed click beetle has two black eyespots behind its head. An Australian moth caterpillar has eyespots that are normally hidden in the folds of its body. When it flexes its hind end, the folds open like lids to reveal the “eyes.”

Patches of color that do not look like eyes also make effective startle displays. These colors are often hidden until an animal flees. The sudden appearance of this flash coloration can stop a predator in its tracks just long enough to let the prey escape.

A red-eyed tree frog, for example, usually blends in with the leaf on which it sleeps. If a predator bothers it, the frog first pops open its enormous red eyes. Then it leaps away, turning from a plain green frog into a rainbow of color as its orange-footed legs unfold and its blue and yellow sides appear. This sudden splash of color startles the predator and buys the frog time to get away.

Octopuses also abruptly give up on camouflage when they are under attack. An alarmed octopus can burst into startling colors or patterns in less than a second. A fish or turtle that sees its intended meal suddenly turn black or zebra-striped is often scared away.

Many kinds of stick insects, grasshoppers, butterflies, moths, and other insects also flash bright colors when fleeing a predator. The colors disappear when they leap or fly to a new spot and fold their wings. They then blend in with their surroundings as they sit perfectly still.

Sometimes just a spot of color can do the trick. The shingleback skink of Australia is a stumpy, short-legged lizard. Its earth-tone colors usually hide it. However, the skink startles potential predators by suddenly opening its mouth and sticking out its thick, blue tongue. It also huffs and puffs, hissing like a snake. Another Australian lizard that uses this startle display is the blue-tongued skink, named for its turquoise tongue.

An Australian legless lizard called the excitable delma does not have startling colors, but it still spooks predators with its behavior. If bothered, this animal twists and turns its body violently as it slithers away. This odd behavior may startle and confuse a predator.