Flea, line drawing.
- Andrew Howells
- © Australian Museum
Fleas belong to the Order Siphonaptera.
What do fleas look like?
- 0.5 mm - 10 mm in length but most are shorter than 5 mm.
- Very thin as if pressed from the sides.
- Covered with hairs and spines directed backwards, some in comb-like formations.
- Appears hard.
- Very short, held in a groove hence often difficult to see.
- Never longer than body.
- Very small or absent.
- For piercing and sucking.
- Six legs.
- Hindlegs enlarged and modified for jumping;
- Have claws modified for clinging to feathers and hair.
- Cerci (tails) absent.
Where are fleas found?
- On mammals and birds (rarely) among hairs or feathers.
- Few are found on semi-aquatic animals such as the platypus, but never on marine mammals.
What do fleas do?
- Fleas are external parasites. They maybe found alone or in large numbers on suitable hosts.
- When disturbed they jump. They can jump incredible distances.
- They feed on blood.
- They are active during the day.
What looks similar?
- Flies that do not have wings can be mistaken for fleas. Unlike fleas, wingless flies are never thin as if pressed from the sides.
- Lice differ from fleas in that they are flattened as pressed from above, do not jump when disturbed, and can occur on fully aquatic hosts.