Years ago, as a junior writer for the Washington Post, I wrote a piece about fleas being able to smell potential hosts up to 12 miles away. Everyone fact-checked it and said it couldn’t possibly be true. It’s not true that fleas can smell blood from great distances. But they can sense carbon dioxide (CO2) at extreme distances. There are still few natural predators of the flea so they have little need to evolve in that way and so we are stuck with them forever. Have you ever wondered if fleas can smell your blood? If they can, is it the up-to-the minute fresh blood that makes them crazy, or only dried blood? Though, typically it doesn’t matter. If a flea finds blood at all, it will begin to feast. Once the flea begins its feast, it doesn’t care about how long ago you were injured – it just wants a meal. The mosquito bites you and leaves a nasty itchy welt on your skin, you step on the black widow spider and end up with a red splotch that disappears in a few days, and you get stung by the wasp on your finger. But one day you wake up to find that flea bites just don’t seem to go away. You shrug it off and wonder why and then 5 minutes later realize that fleas do bite all of the time, even though you have never had problems before. Let’s find out if fleas can smell blood, because they definitely can. Fleas can sense the carbon dioxide in humans and animals and follow the trail up to 12 inches from a source of detected CO2. While it’s not known how close fleas need to be to smell your blood, it’s possible that your pet (or you, if you’re at risk for flea-borne illness) gives off a scent that draws fleas to the area. Farther away from an animal or person, it’s thought that fleas may be able to smell certain chemicals that emanate from hosts such as ammonia.

Can Fleas Smell Blood

Do fleas have the ability to smell blood?

Yes, fleas have the ability to smell blood. Fleas are able to smell carbon dioxide (CO2) that is exhaled by a living creature. The CO2 comes from the carbonic acid in your blood and moves along your breath on its way out of your body through your lungs. This is one way fleas can detect whether or not there is an animal nearby with blood circulating through its veins.

Flea larvae also use their sense of smell to find a host. They use this sense when they’re looking for food, as well as when they’re looking for a place to hide in order to wait until full adulthood so that they can begin laying eggs on their new host!

How do fleas find you?

We know that fleas can sense your body heat, but they also have other ways of finding you. They use the carbon dioxide you exhale to find you and vibrations from your footsteps to get close enough for the jump. Fleas are sensitive to light and will not approach during daylight hours, but once night falls their eyesight kicks into high gear.

Fleas rely on a variety of senses when it comes to finding their human hosts. They have excellent hearing and can detect vibrations through your floorboards or even under carpeting; this helps them locate their prey in the dark without having to see it clearly first hand (which is difficult due to our skin’s pigmentation). The smell of your blood is another powerful attractant: flea saliva contains an enzyme called phenoloxidase which breaks down hemoglobin into iron-rich compounds that give off a distinctive scent when released by feeding ticks or mites (or even just walking across carpets).

Fleas can smell blood and they use that ability to their advantage.

Fleas are very, very good at smelling. They can smell blood through their antennae, which is how they find hosts to feed on. They don’t actually smell blood directly; rather, they can smell the compounds in it. This includes carbon dioxide and lactic acid – compounds that are released from your body when you breathe or sweat.