Updated on April 3, 2023
There are a lot of tiny terrors that can invade your home, many of which are as small as a sesame seed. For some, these critters can be disgusting. For others, a source of fear.
But there are some out there that have earned a special hatred because they feed on blood. These include bed bugs, leeches, mosquitoes, ticks, and (of course) fleas.
In the pest world, one hears a lot of old wives’ tales about various critters, but you might be surprised to find that some are actually true. In fact, fleas are the subject of many such tales in which there is factual evidence behind a lot of things that pest-related websites insist are purely fiction.
One such question often asked is: can fleas can live in human hair? Let’s take a moment to look into that and see where the truth actually lies.
Can Fleas Survive in Human Hair?
We’ve heard this question many times, and in almost every case, there is either an outright denial or a “safe”, noncommittal answer. But we’re here to give you a solid, scientific answer, as well as any variations to those facts.
So let’s start with the common counter question, then break things down to examine all of the facts.
Note: For those who always skip to the last page in mystery novels, the answer is: yes, fleas can live in human hair, but not for long with one exception.
Is It Really a Flea?
This is the ultimate question of every skeptic, “Are you sure that’s what you saw/heard?”
Sometimes this question plants a seed of doubt, while sometimes it only makes the person more determined to prove their claims. But say what you will, this question also has a scientific basis, and in the world of pests, it’s often easy to blame the wrong critter.
Here are some bugs often confused with fleas and how they are different.
Bed Bugs
Bed bugs are flat and rounded. Like fleas, they drink blood, but their bites are different. Unlike a flea, bed bugs aren’t very good at climbing under clothes or gripping the skin, so they’ll leave a trail of bite marks where your movements have dislodged them during the night.
Bed bugs are also unable to jump, which is one of the most famous abilities of a flea. Due to their poor grip, bed bugs prefer to attack exposed skin and it’s pretty rare for them to attack the scalp (if you have hair there, that is).
Lice
Like bed bugs, lice prefer human hosts, but these little nasties actually live on the host.
There are several different species, often named after the portion of the body they prefer, such as head lice, body lice, and pubic lice. They have a more oval abdomen and distinctive head.
Mites
One of the most common kinds of indoor arachnid, mites can be bigger than bed bugs or so small they’re almost impossible to spot with the naked eye.
Their bodies are rounded and they’re actually decomposers, feeding on shed skin cells or similar waste. However, there are times these critters can get over-enthusiastic and bite you while feeding.
Ticks
Ticks are yet another arachnid pest that prefers to live almost exclusively outdoors. They have a similar body shape to bed bugs but are much better at keeping a grip.
In fact, they can remain attached to their victim for several days, leaving behind a red lump that can blister or bruise and lasts for a couple weeks. They much prefer other animals over humans, but won’t turn down a good blood meal when they sense one.
As for the Flea…
Fleas are very good at remaining on their host and can skitter across skin or navigate fur like a pro. Their bites leave small, itchy bumps that are surrounded by a red halo.
Related: Flea Bites on Kids (Identification and How to Treat)
These bites are most often found on the legs and feet, but this isn’t always the case. Also, unlike all of the critters we’ve just covered, fleas have a vertical, seed-shaped body.
Fleas can also be identified by the frass they leave behind (referred to as flea dirt).
The Myth of Fleas and Humans
And now we come to the part that most other pest sites are usually unwilling to discuss – the relationship between humans and fleas.
Any person who has pets and dealt with fleas will know that fleas can and do bite humans, even though there’s still this old wives’ tale that fleas only attack pets. This is due to partial information, however.
Another myth is that fleas can’t live on humans. Again, this is a myth based on partial information.
Here at RMC, we pride ourselves in giving out the most accurate information possible, and when you point out a mistake, we actually go and fact check ourselves again using the information you provide. If we’re wrong, we admit it.
And it’s this attention to detail that allows us to boldly say that the above claims are wrong because there are actually…
Related: Can Rubbing Alcohol Eliminate Fleas?
Different Kinds of Fleas for Different Hosts
We won’t get into too much depth about different species of fleas, but we do need to touch upon three of them, because this is where people get things wrong.
They say the devil is in the details, and the biggest mistake most websites and non-academic (and, let’s be honest, even some sources claiming to be academic) sources make is to only discuss a single species of flea.
Cat Flea
The first of these is the cat flea (Ctenocephalides felis), a flea so common that just about every website out there is discussing this very species when they talk about fleas.
Cat fleas prefer cats (obviously) but will attack dogs and other pets. They will also attack humans under certain circumstances.
Dog Flea
The second is the dog flea (Ctenocephalides canis), a species that looks very similar to cat fleas but prefers dogs over cats.
These are almost as common as the cat flea as well, leading a lot of sources to mistakenly believe the two are one and the same species. Dog fleas will also attack humans under certain circumstances.
So before we get into the third flea species, it’s important to denote that most pet-related fleas will attack humans. See, when a critter feeds on a specific host (be it plant or animal) for long enough, their bodies adapt to that specific food source.
Humans, cats, and dogs all have very different blood contents, so a cat flea will see cats as a sirloin steak with all the trimmings and humans as a piece of wilted iceberg lettuce.
A human will normally think eating out of the trash is disgusting, but miss a few meals and suddenly it doesn’t matter. The same is true of fleas.
If a cat flea isn’t near a cat, it will seek out the nearest source of blood. This often means humans. And yes, they can stick around on a human in the hopes they’ll be transported to their preferred food.
Read Also: Can Fleas Survive in Water?
Human Flea
But the third type is the human flea (Pulex irritans), formerly known as the house flea. This species prefers humans over furry mammals and sees patches of human hair to be the perfect shelter.
As with other species of flea, the human flea is adapted for the blood of their host and can only gather the proper nutrients for reproduction from that host. However, also like other fleas, the human flea will feed on other critters when humans aren’t available.
So Can Fleas Live in Human Hair? Assembling the Evidence
When talking about species that are adapted for living and breeding of their host, that flea will tend to spend its entire live on the preferred host. However, there are times when the flea becomes dislodged and will feed on a different critter while waiting for a chance to infest their preferred host.
A hungry flea will bite humans on the legs or feet (unless the human is sitting or laying down), but usually only bite a couple of times before jumping ship.
With the exception of human fleas, flea species find human hair to be more difficult to take shelter in. This is compounded by the fact that human blood lacks the nutrients they need to reproduce.
Thus, most fleas can hide in human hair, but they will try to leave at the first sign of a more viable host.
Species other than human fleas are most likely to infer your hair if the infestation in your home is so severe that food is sparse. They are also more likely to stick around in your hair if you aren’t grooming regularly.
Related: How Much Do Flea Exterminators Cost?
The Final Verdict
Can fleas live in human hair? Yes, although human fleas are the only species that prefers humans.
What increases the risk of fleas in your hair? Poor hygiene and/or major infestations will greatly increase the risk, although fleas may briefly hitch a ride in your hair while looking for their preferred food.
Can fleas survive in human hair? Yes, but outside of human fleas, human blood lacks the exact nutrition a flea needs to breed, meaning they can’t lay any eggs.
Morgan is a certified entomologist and pest control consultant and a member of the National Pest Management Association.
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