A flea can jump up to 7 inches vertically and 13 inches horizontally to propel itself onto a new host. Fleas are known for their incredible jumping ability, which is due to the structure of their legs. The hind legs of fleas are long and strong, and they have a special joint that acts like a spring to propel the flea forward. This allows fleas to jump up to 150 times their own body length, which is an incredible feat!