Fleas are parasites that feed on mammals. However, unlike other parasites that live in the intestines of mammals, the flea is an external parasite that feeds on blood. A female flea is capable of producing up to four eggs after each feed. Fleas can reproduce rapidly under favourable conditions and can quickly grow from only a couple of fleas to a huge population.

Adult fleas are very small. They are rarely more than 2mm long and are dark red to brown in colour. Their bodies are flattened on the sides and they have backwardly projecting spines. Their legs are stout and spiny and the hind legs are enlarged. They don’t have wings but use their big hind legs to jump up to 30cm, a long distance for such a tiny insect.