Link Between Pubic Lice and Shaving Is a "Running Joke" for Sex Experts

"It’s been a running joke for years that we’re kind of disturbing the rainforest that they live in."

Natural selection has shaped the form, function, and life of the pubic louse, like every other creature on the planet. These so-called “crabs,” which dwell in pubic hair, are definitely gross looking, but the scientists who study them maintain that they’re fascinating creatures that have evolved to coexist in the pubic fuzz of their favorite companion, humans. It’s hard not to wonder: Can they survive our most aggressive pubic hair pruning techniques?

Dr. Peter Leone, an infectious disease expert at the University of North Carolina, is well versed in this life history of pubic lice. To understand whether shaving will actually affect our risk of getting pubic lice, he says, we should first understand some things about the anatomy of the lice themselves.

Why Pubic Lice Love Human Pubes

The specific species of pubic lice that infect humans, Phthirus pubis, co-evolved with humans as they diverged from great apes over millions of years. Over the course of this time, they gained the unique ability to reproduce in human pubic hair. Human pubic lice possess a unique set of claws that are perfectly suited to latch on to the coarse hairs near the genitals. Once they latch on, they can reproduce and create a sustained infestation.

“It’s kind of bizarre but that’s the way things have evolved,” Leone tells Inverse. “They have to be anchored in order to be able to procreate and reproduce. So they actually clasp their claws onto the hair follicles to do that, and the spacing in hair on your head is too close. Pubic hair has spacing that’s far enough apart where it fits for them.”

pubic lice
Pubic lice have claws that can latch on to pubic hair. 

Why Shaving Probably Isn’t Enough

Given their unique claw size, it would make sense that shaving pubic hair would be a good way to prevent pubic lice. Leone suggests there is some truth to that idea: “Actually if you shave your pubic hair or get a Brazilian you actually have a much lower risk of acquiring pubic lice,” he says.

It’s hard, however, to find a studies that have investigated that notion specifically. Neither the CDC nor the American Sexual Health Association list shaving at all in their discussions of personal pubic lice prevention.

Pubic lice can’t reproduce in other hair types, but they can survive outside the pubes, so shaving probably isn’t a bulletproof method to prevent infection.

Though we lack evidence about how shaving impacts personal risk, there is widespread speculation about how pruned pubic hair is affecting population of public lice worldwide.

Are Pubic Lice Going Extinct?

Leone says that there’s a running joke among pubic lice experts: As more and more people get Brazilian waxes or shave their pubes, we’re actually destroying their habitats.

“It’s been a running joke for years that we’re kind of disturbing the rainforest that they live in, and we may have the extinction of pubic lice,” he says.

pubic lice
Pubic lice have claws that can latch onto hairs. 

The idea that pubic lice were going extinct has actually enjoyed some time in the spotlight. The Daily Show ran a segment in 2013 equating the “rise of Brazilian waxes” to the destruction of the rainforest. A handful of scientists have argued that going bare down there is spelling disaster for pubic lice, but they didn’t really hold up against widespread scrutiny. That’s because they were based on anecdotal evidence or were only able to show correlations between the number of people who wax worldwide and the people who reported cases of pubic lice.

Leone says that as long as there is coarse hair in the world, we will have pubic lice, no matter how many people decide to shave their pubes.

“They’re still around,” he adds. “You have to have a real big population- level effect to really get these [lice] to not be persistent.

How Do You Treat Pubic Lice?

Fortunately, treating pubic lice is fairly routine — so routine, in fact, that pubic lice cases aren’t even a reportable condition for most health departments. There are varieties of readily available shampoos and some topical medications that should take care of the infestation.

Leone adds that it’s also important to clean sheets thoroughly. They can survive off the body, though not for long. Their unique living preferences aside, public lice are much like normal head lice — better tackled with medicine, not a razor.