Fleas are small ectoparasitic insects
The Fleas infect mammals (including humans) and some birds.
Fleas feed on the blood of their hosts through their piercing-sucking mouthparts.
After each blood meal, female fleas lay from four to eight eggs of round or oval shape (0.5 mm long), smooth-shelled and whitish. If conditions are favorable, the eggs hatch after a few days and out comes a worm-like larva, which in the usual host species, are at least 1.5 mm long.
There are over 2500 species of flea described to date.