By: Alisa Wei

New data shows the “tails” of butterflies may help them survive attacks from predators. These tails may have evolved to distract predators from grabbing a butterfly’s head or abdomen.

“A lot of these butterflies display tails, and we don’t really know why.” says evolutionary biologist Ariane Chotard. Chotard studies the wings of swallowtail butterflies at the National Museum of Natural History in Paris.

Chotard and her colleagues collected sail swallowtail butterflies near Ariege, France. Sail swallowtail butterflies got their name from the two tails on their wings, similar to those of a swallow. They noticed 65 out of 138 butterflies collected had at least one damaged wing. Out of the 130 damaged wings, 8 out of 10 had a damaged tail. This statistic shows that the tails may be used as an escape device.

The team captured several songbirds in order to test out their theory. They made fake butterflies using cardboard bodies and real swallowtail wings.

The songbirds started to attack the butterflies. The team noted that nearly 3 out of 4 strikes were targeted toward the lower body. There were 4 out of 10 strikes that hit the tail, more than any other part of the body.

Chotgard and her team believe the tails are like lizard tails, they break off when attacked by predators. This is a useful feature, but Chotard says the missing tails may slow down a butterfly in flight.