Why Can Fleas Jump So High?

Fleas are able to jump so high because of an energy-storing mechanism inside their leg. Researchers have studied this mechanism with high-speed video cameras. They have found that the flea’s legs contain a spring, which is compressed and released to release energy at the right time to allow the flea to jump.

To study the mechanism of their jumping, Dr. Gregory Sutton, a professor at the University of Cambridge, conducted computer modeling and analyzed high-speed video of fleas. The results of the study show that fleas jump between 50 and 100 times their body length. But despite their ability to leap so high, the insects have to rest their legs on the ground first before they can push themselves off.

The scientists filmed fleas jumping 51 times. On 45 of the jumps, the flea’s knees stayed on the ground. However, in six jumps, the knees cleared the ground. That suggests that the flea’s force didn’t transfer from its legs to the ground.

The resilin pads that fleas use for jumping allow the flea to accelerate quickly without sacrificing structural support. Without this resilin pad, fleas wouldn’t have the ability to jump much higher than normal fleas.