What do fleas look like and do they jump? - briefly
Fleas are tiny (1–3 mm), dark‑brown or reddish insects with a laterally flattened body and enlarged hind legs adapted for leaping. They can spring up to 150 times their own length, using a resilient protein pad that stores elastic energy.
What do fleas look like and do they jump? - in detail
Fleas are tiny, laterally flattened insects typically measuring 1–4 mm in length. Their bodies are covered with a hard, chitinous exoskeleton that repels water, enabling them to move through fur and feathers. The head is small, bearing compound eyes that are reduced or absent in many species, and short antennae concealed in grooves. Mouthparts form a piercing‑sucking proboscis capable of penetrating the skin of mammals and birds to feed on blood. Legs are long relative to body size; each hind leg ends in a powerful, spring‑loaded tibia‑tarsus complex that stores energy in a protein called resilin.
Jumping performance:
- Acceleration exceeds 100 g, allowing a flea to launch up to 150 mm vertically, equivalent to 30–40 times its body length.
- The take‑off angle is typically 45°, optimizing distance.
- A single jump can cover 10–20 cm horizontally, sufficient to move from a host to the surrounding environment.
The flea’s jump relies on rapid contraction of the femoral muscle, which compresses the resilin pad. When released, the stored elastic energy propels the insect, making the leap the fastest known animal movement relative to body size. After landing, the flea quickly re‑engages its claws to cling to the host’s coat or skin.