Do fleas lay eggs in human hair?


It’s unlikely for fleas to lay eggs in human hair. Cat fleas don’t breed on humans. In a natural setting, females can’t produce eggs on a diet of human blood. Also, fleas can only jump to the height of a person’s ankle. Once on a human, fleas quickly take a blood meal and then immediately leave. They don’t wander around.


Humans aren’t Preferred Hosts

Host Specificity

Cat fleas don’t have host specificity. They’re capable of feeding on a large range of warm-blooded mammals, including humans. However, they do have preferred hosts, such as dogs, cats, opossums, and raccoons. Man isn’t a preferred host.

Fleas & Human Blood

Humans make poor hosts for cat fleas. A diet of human blood alone can keep fleas alive, but they’re unable to reproduce. Females only lay eggs after feeding freely for days, and doesn’t happen outside of lab conditions. Even with enough feeding, their fertility is greatly reduced on human blood.

Fleas are Poorly Adapted for Living on Humans

Fleas have co-evolved along with their primary hosts. Thus, the physical adaptations of cat fleas are well-suited for living on small mammals with dense fur. For example, their bodies are covered with backwardly-directed spines and bristles. The spination helps them attach into an animal’s hair coat, and prevents them from being dislodged.

Flea survival is largely governed by host grooming and the insects’ ability to remain on a host. Fleas have difficulty jumping onto humans without falling off due to the lack of body hair. Only 1 of 10 attempts are successful. Even if settlement occurs, fleas are easy to see against hairless human skin. They often get picked off before having a chance to feed.

Bites on Humans are Incidental

Fleas sometimes bite people who live in the same habitat as an infested animal. This typically occurs when the primary host is absent or scarce. In homes, it’s not uncommon for fleas emerging from cocoons to bite people before finding and colonizing their preferred host.

Once on the primary host of a cat or dog, adult fleas remain there. They feed, mate and lay their eggs directly on the host. In contrast, when fleas feed on people, they’ll take a blood meal and then immediately leave. Fleas don’t breed on humans. Blood meals last 4.4 minutes for males and 7.4 minutes for females.

Fleas can’t Reach Human Hair

Cat fleas can jump to a maximum height of 7.9 inches. This is as high as a person’s ankles, which is where flea bites tend to be concentrated. Fleas bite readily without roaming around. They’re unlikely to climb to a person’s pubic area, much less their head. These areas are too far from the ground (unless the person is sitting/laying on the floor, or a flea-infested pet is allowed in the person’s bed).


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  • Catiy September 13, 2016, 4:07 am

    That’s exactly true but what happens if your laying down and a flea get to your hair? Will it jump right out? Will it stay there? What happens if a flea gets in you ear?

    • Adam Retzer September 13, 2016, 4:04 pm

      It’s possible for fleas to get in hair if the person is laying down. However, fleas don’t live on people, nor will they mate or lay eggs there. Fleas sometimes take a blood meal from people if the primary host isn’t around, but they’ll leave immediately after feeding. If they can’t find way off, they may remain there a little longer but prefer not to.

      I’ve never heard of a flea going inside a person’s ear. There’s no benefit for them to do so. If they happened to somehow wander inside someone’s ear, I’d image they’d exit immediately.

  • Izz November 30, 2016, 11:56 pm

    That is not true. I even lost hair before I realized my home was infested with fleas. And we had them at least several months before we found out. I had severe hair itch but would not find any pest except lots of small salt looking dandruff. After some time I found three fleas in my toddlers hair with some eggs and black speck feces. Four weeks of bombing-cleaning-poisoning hell fleas are still here and we are calling pest service. I don’t know what type of fleas are mine (cat, dog or rat), but they are indestructible. Especially with little kids rolling around. Also it seems that our dog’s fleas developed resistance for Front… brand of flea control. Flea collars don’t work either. This are some new improved mutants and I wouldn’t wish them on anybody.

    • Adam Retzer December 1, 2016, 12:27 pm

      Those characteristics you’ve described certainly don’t sound like fleas. I won’t dispute what you’re experiencing though. I’m sorry you have to deal with this, and hope the pest control service resolves the problem.

      • Izz December 3, 2016, 3:56 am

        Well they are. Simple test with bowl of water and few drops of liquid dish soap with incandescent light just above and there they are drowned in it (several fleas in every room in the house by day three after bombing). Buy the time you find few feeding on your little child there are literally thousand of larvae in the house. Check larvae you tube videos. And you do have type of fleas that readily find people as secondary hosts. Please do some research. (There are also number of people that are allergic to flea saliva.) I’m afraid that mine are quite adaptable. Also I talked to pest control and they confirmed that in most cases of fleas they got lately; pets were on some kind of constant flea control. The groups on line in which lately I spent to much time reported resistance of fleas to imidacloprid pesticides. Also they have been reported lice pesticide resistance. This is off topic; just to show that today’s bugs did mutate. Kind of like MRSA. I found a way to kill flea before jumping of the host. Simply grab flea between two fingers then go and pour liquid dish soap on top of the fingers. Now you can safely open the fingers (bug will be to soaked to jump off); and press it between your nails. And then you have dead bug, and many more to go.

      • StarHaze March 2, 2017, 1:25 pm

        Says the guy that only mentions cat fleas in the article, as if thats the only type of flea that exists, lol

        • Adam Retzer March 2, 2017, 5:15 pm

          I’ve stated many times on many pages, especially the primary pages on this site, that this website is focused on cat fleas. This is because cat fleas are the predominant species of fleas found in domestic settings.

  • Mj February 19, 2017, 7:54 pm

    My dog has fleas n they keep staying in my children head how is this possible.

    • Adam Retzer February 22, 2017, 2:36 pm

      Flea eggs are laid on the host animal. The eggs fall off into the environment within a few hours of being laid. Most develop in carpeting, but they can drop anywhere the infested animal spends a lot of time. So, if your children are spending a lot of time on sitting/laying the floor, then newly emerging fleas would have access to them. If the dog is allowed to get onto your children’s beds, then it’s possible that fleas are developing there as well.

      It’s strange that the fleas are staying on your children’s heads. Fleas don’t usually stay on people. They feed and then leave. It’s hard for me to determine what’s going on without knowing the full details on your situation.

    • StarHaze March 2, 2017, 1:26 pm

      Probably have human fleas not dog fleas, look it up

      • Adam Retzer March 2, 2017, 5:21 pm

        This is possible. Not probable. Humans fleas (P. irritans) are relatively rare compared to cat fleas (C. felis) and dog fleas (C. canis).

        Further, human fleas don’t live on humans. They are found on humans when they feed. The FleaScience website isn’t focused on human fleas, but you can find more information here:

  • StarHaze March 2, 2017, 1:24 pm

    So why is this article not discussing human fleas? Cat fleas live on cats, but human fleas can live in human hair, along with any other mammals. Whoever wrote this hasn’t done much research.

    • Adam Retzer March 2, 2017, 5:27 pm

      I’ve addressed this in your other comments, but this website is focused on cat fleas (C. felis). This is because this species is by far the most common species found on dogs, cats, and in homes. Human fleas are a relatively rare species.

      Regardless, human fleas (P. irritans) don’t live in human hair. They live in the human environment. And, just like cat fleas, are typically only found on humans when they feed. Here’s an article with cited information.