Our encounters with fleas are now thankfully limited to the unwanted infections of our pets, but for most mammals and birds they remain a continual annoyance. There are about 2000 species of fleas that suck the blood of a wide variety of hosts, each adapted to their own ecological niche. They belong to the order Siphonaptera but appear to be heading for reclassification with the Mecoptera, or scorpion flies.
The major problem a flea faces is to land on a moving host. It has solved this by a spectacular ability to jump, which so impresses us that it leads us unwisely to extrapolate to the size of buildings over which we might jump, if only length and mass scaled in the same way. How does such a small creature (a rabbit flea is only 1.5 mm long and weighs just 0.45 mg) jump huge distances with such speed and power?...
