These renowned jumpers, brown and barely 1/16 inch long, have long legs that act like springs to catapult them far from harm.
Where they live
In your house—adults are most likely your dog or cat. Their larvae are microscopic, crawling around in your pet’s bed or your carpet. Got fleas but no pets? Squirrels, feral cats, mice, and other critters also carry fleas.
What they do
The adult fleas suck blood and leave you and your pet scratching the itchy bites. You’re most likely to get bitten on your lower legs. Look for a darker spot in the center of the bite. Famous for their role in the black plague, fleas still carry disease and parasites.
How to deal with fleas
New flea treatments for pets mean fleas aren’t as common as they used to be. If you suspect them in your house, walk across carpets with tall white socks on and look for little black bugs jumping up. Scout your pets, separating their hair so that you can see the skin on their bellies and necks. If you find fleas, get pets the proper treatment. No pets? Make sure wild animals aren’t getting into your building.
Getting fleas out house for good means keeping humidity low, vacuuming regularly with a beater attachment (don’t forget couch cushions and under the bed), and washing pet bedding once a week. After you vacuum, put the bag or canister contents in a plastic bag, tie it off, and throw it away right away—there’re fleas in there! If this doesn’t do the trick, call a professional.
Fleas fact sheet, 80k pdf file, at Cornell's Insect Diagnostic Laboratory