The Secret Life of Fleas

Adult fleas aren’t very clever and they aren’t particularly sneaky. (In this way, they are often thought of as being similar to people—the teenagers are always much brighter than their parents.)

    If you can pass an eye test at the DMV, you should be able to see adult fleas on your pet.  Adult fleas want to spend all of their time on your tasty pet, so they aren’t hard to find.  Both male and female fleas love to drink blood, and after a good blood meal the females will lay about 40 eggs per day.  Once the feasting has ended, most fleas leave little black specks on your pet—these specks are called “flea dirt,” which is a nice term for flea poop!

    (Here’s a fun Home Science Project. If you don’t believe that those little blacks specks are flea poop, then comb some of them out of your pet’s fur and put them on white tissue paper.  Add a few drops of water. If the tissue turns red under those little specks, then it is because you have just reconstituted dried blood, which is the main ingredient in flea poop.)

    Unlike the older generation, young fleas are stealthy and cunning.  It is the youngsters that lead the secret life of fleas. Since baby fleas can have over 800 brothers and sisters, you would think that they would learn to share—but they don’t.  In their world, it is every bloodsucker for himself, and they each have their own way of surviving.

    Flea eggs are very small and tend to roll off of the pet and into the environment.  Depending on the climate, it can take a few weeks to several months for a stealthy baby flea to grow up into a stupid adult flea.  For the first few weeks of its life, the flea egg patiently waits  (along with his 800 siblings) for the right conditions to advance to the next phase of its life cycle.  About half of a flea’s life is spent as an egg, which means that if you’ve seen those dumb adult fleas then there are definitely a lot of sneaky flea eggs in the environment.

    When the time is right, the egg will hatch and out pops a flea larva.  The larva eats “organic debris,” which is the scientific way of saying that the larvae eat cat, dog or flea poop, dead grass, old leaves, etc. Not being very choosy, flea larva will also eat tapeworm eggs—which eventually gives your pet tapeworms.  The highest concentration of flea larvae can be found in the bedding and areas where your pet sleeps.  Young fleas love carpeting because it provides them a safe and dark place to grow up.  And they really love homes with air conditioning, because it means they can continue their life cycle year round.

    After they’ve eaten enough “organic debris,” flea larvae become flea pupae. This is a lot like a butterfly developing in a cocoon (except that butterflies are beautiful and don’t suck blood).  As pupae, the fleas are coated with a sticky substance that picks up dirt and grime to act as a sort of natural camouflage.  Inside their cocoon, flea pupae have special sensors that look for your pet’s body heat, as well as motion and carbon dioxide detectors.  I told you that fleas had secrets!

    Flea pupae can live happily inside its cocoon for months and months.  In fact, it won’t emerge from the cocoon until one of its sensors indicates that a tasty pet is nearby. Within two days of its first blood meal, the female flea is laying eggs, and the cycle begins again.

    There are many types of flea control products—some products target the juvenile fleas, and others kill the adults.   While some products actually do work, there are other readily available flea control products that may be dangerous for your pet.  Prove to your teenagers that you still have smarts, and ask your veterinarian which is the best product for the family pet.