Fleas are among the most outstanding jumpers in the animal kingdom.

A common cat flea (Ctenocephalides felis) can vertically jump about 18–20 cm and horizontally jump about 33–48 cm — which, scaled up, would be equivalent to a human jumping about 300 meters.

The acceleration of a flea's jump is astonishing — within the 1 millisecond of takeoff, the flea experiences an acceleration of about 140 times Earth's gravity (140 G), which is over 20 times greater than the acceleration of a space shuttle at launch.

The flea's jumping mechanism relies on its specialized hind leg structure: the hind legs contain an elastic protein called "resilin" — one of the most efficient elastic materials in nature (with an energy recovery rate of up to 97%).

The flea first contracts its hind legs, compressing the resilin pad to store energy, then releases it instantaneously — launching itself like a catapult.

The jump is not random — fleas can sense the host's body heat, carbon dioxide, and vibration signals to direct their jump.