So I’ve discussed a bit how animals will adapt to humans using crows as an example. But there are some other examples that aren’t so fun. Really fascinating and potentially cool, but not fun, at least not for humans. Specifically, I’m talking about pathogens.
But discussing antibiotic resistant superbugs is a major downer, so to kick it all off, today I will tell y’all a tale of parasites. You know, happy stuff.
Lice, if you are not aware, is a broad term describing 4000 different species. While a number like that may be enough to make your skin itch and crawl (or not, just don’t think about little buggy foots scurrying over your arms), humans only have to worry about 3 species: head lice, body lice and pubic lice (aka crabs).
Even if you managed not to share a hairbrush with anyone in grade school, you probably encountered head lice at some point, either cause you had to smell your sibling while they underwent the “mayo cure” or missed your friends while they were quarantined at home. Head lice are small, whitish and have been around for 7 million years. They’ve evolved with and bothered humans since our common ancestor to the chimp was around to scratch at them. Pretty impressive.
Body lice, on the other hand, have been around for a lousy 107,000 years. And where did they come from? They evolved from head lice as humans began wearing clothes. Despite what the name implies, body lice begin their lives in the seams of clothing, where they will eventually lay their own eggs, with a relocation to the skin for easier feeding inbetween. If you’re wondering why such clothes crawling critter is not a bigger problem, it’s because body lice need a consistently warm environment that, in humans, is best fostered by wearing the same clothes for weeks on end without washing. Something early humans did a lot, until someone discovered laundry. As a result, in modern times, lice favor the homeless and destitute (another reason why it’s so important to donate clothing to local shelters and charities).
Now, where does everyone think pubic lice came from? If you guessed that they evolved from body lice, well…NOPE. Pubic lice can inhabit any course hair (eyebrows, facial hair, etc) on the human body, but they are most closely related to lice found on gorillas. Now, considering that their easiest mode of transmission is via skin-to-skin contact…well, let’s just say I have serious questions for the early human who first caught crabs. Probably so did their significant other. And the gorilla.
Look! I caught crabs.
So that last tidbit was mostly a bonus, but pubic lice, as have head and body lice, have evolved with humans and their habits. In the case of head lice, we deal with them enough that they are adapting and becoming resistant to our extermination methods, which will bring me to tomorrow’s topic.
Cheers!
Sources
Stewart, Amy. 2011. “Wicked Bugs”. Algonquin Books of Chapel Hill. Chapel Hill, NC.
Daily Science (blog) 