Why Are Fleas Hard to Squish?

Fleas have an unusual structure that makes them hard to squish. They have an outer shell made of chitin, a polymer that is commonly found in fungi. It is also found in the internal shell of cephalopods and crabs. This structural feature probably evolved millions of years ago, when fleas evolved from aflies, insects that were similar to fleas. Scientists believe fleas evolved chitin as a natural barrier to protect themselves from predators.

Fleas are tiny parasitic insects that feed on the blood of a warm-blooded host. Their reddish-brown bodies are flat and hard, and their wings are absent. They feed by biting the skin of their host. Fleas can live up to a year in the presence of a host animal, but will only survive for one or two weeks without a host.

Fleas can be difficult to squish because their legs are designed to hold firm on a host. They also use their strong exoskeleton to leap out of harm. Fleas are small and can cause itching and irritation. Squishing a flea can be very difficult and requires a lot of effort. When you have squished a flea, it will have blood on its body. This is because it has just eaten a blood meal.

Fleas can lay their eggs in warm, humid conditions. If the environment is not suitable for hatching, their eggs can stay dormant for months. They are then stimulated by heat or humidity.