Meanwhile, the Neanderthals all died. You do the math.
Human beings like to think that we got where we are on the evolutionary ladder through the power of our own ingenuity and our ability to punch the rest of nature into submission. But evolution doesn't work that way -- we humans are what we are due to help from a series of creatures most of us have very little respect for. So let's take a moment to appreciate the fact that ...
To understand how dogs' ancestors totally saved humanity's collective ass, you have to go back about 40,000 years to when Neanderthals and modern humans walked the Earth at the same time. Contrary to popular belief, Neanderthals weren't the stupid oafs many assume they were. Just like early humans, they knew how to use tools, make fire, and practice social rituals. That's better than most of us could manage today if tossed out into the wilderness.
Most of you would be 80 percent of the way dead by this point.
In fact, they even had similar-sized brains, indicating that they likely had a language. But one striking difference between the two species was that humans lived and worked alongside dogs, while Neanderthals had a much less subtle use for canines (i.e., dinner). The addition of dogs into a hunting party has been shown to increase food yield by 56 percent, giving early humans a huge advantage over the competition.
But they couldn't have just stolen young pups from their dens and trained them into domestication. It turns out that domesticating a wild wolf pup is incredibly difficult and time consuming, even for modern humans. People of the Mesolithic period had better things to do. Luckily, the wolves came to us -- when humans began to build settlements instead of living a nomadic life, one of the ultimate side effects was that waste accumulated. Wolves just loved eating themselves some garbage, since it was way easier than hunting.
Michael Blann/Photodisc/Getty Images
Then, as now, no dog could resist the allure of old pizza boxes and tampons.
As wolves ventured closer to human settlements for a taste of that sweet, sweet waste buffet, they evolved to become less afraid of humans. They also, amazingly, evolved the ability to read human gestures and follow the human gaze. If we point or look somewhere, a dog will focus in that direction as well (try that with your stupid cat). As these dogs bred, these traits were passed on to future canine generations and amplified, eventually ingraining their benefits into human culture forever.
At which point they began the transition from alpha predator to alpha sidekick.
Meanwhile, the Neanderthals all died. You do the math.
For as long as humans have walked the Earth, lice have been right there with us. Indeed, many creatures carry lice, and each animal has its very own species. Human lice, cat lice, wombat lice -- they're all different. So you might find it scary to learn that humans have not one but two species that can live on our bodies. Head lice and pubic lice are the ones we have to contend with, but while head lice are little more than an itchy inconvenience that you can avoid by improving your standard of social circle, pubic lice are a burning, infectious nightmare, so much so that our ancestors lost most of their body hair just to get rid of them.
"Cave wife go with shaved look. Ugg like."
"You sick, Ugg; stay 'way from my kids."
Scientists have discovered that we originally caught the human pubic louse from gorillas. But before you get any uncomfortable ideas, it probably didn't happen the way you imagine -- back when our ancestors were covered in thick body hair, we only needed to spend time hanging around gorillas, hopefully platonically, to catch a case of the King Kong crabs. And back then, what we now know as pubic lice were actually whole-body lice. Let that idea sink in for a minute.
Centers for Disease Control and Prevention
"I'm still gonna focus mainly on your junk, but just know that I've got options."
With two different kinds of lice re-enacting the Battle of Helm's Deep on our bodies, the irritation was enough that we evolved to shed most of our body hair in order to segregate the factions to opposing sides of the body. The head lice were free to rule from the neck up and can only survive on the human scalp. The pubic lice were king of the crotch, using the thicker hairs to hold on with their big claws. The armpits, the only other place where pronounced body hair exists, are presumably the Demilitarized Zone. And that's how humans came to look the way they do today: thanks to hordes of tiny crotch-biting insects.
Honestly, worms seem like one of evolution's least impressive creations. You can count the number of things they do on one finger: They squirm around looking gross. But many scientists think that earthworms are pretty much the driving force behind the birth of civilization. And one of these scientists was none other than Charles Darwin.
"I know my shit."
It took Darwin 44 years to research and write a book about earthworms (by comparison, his most famous work, On the Origin of Species, took a mere 21 years). The man fucking seriously loved worms and literally praised them as the most important animals on Earth, crooning, "Worms are more powerful than the African elephant and more important to the economy than the cow." So what's so great about worms? They pretty much prepared the soil for humans to grow food, which would have been impossible otherwise. No worms, no agriculture.
Ryan McVay/Photodisc/Getty Images
"Suck our dicks, Monsanto."
By simply going about their business, eating soil and shitting it back out again, worms have inadvertently been fertilizing and ventilating the ground for millions of years, which turned the soil into something we could actually work with. If not for earthworms, the first settlers in places like Egypt, Mesopotamia, and India would have had to try to build their civilization on a barren foundation of rock and clay. Early humans would most likely have concluded that was bullshit and that farming was for assholes. We might still be hunting mammoths to this day.
So maybe it's not so weird that Darwin was a little too into earthworms. In his best-selling worm expose, "The Formation of Vegetable Mould Through the Action of Worms, With Observations of Their Habits" (God, he sucked at titles), Darwin spends a massive amount of time documenting experiments he did to measure the earthworms' intelligence. By observing a certain way that they dragged leaves into holes in the ground, he attempted to determine if they possessed the ability to reason. He concluded "sort of" in 1881 and promptly died six months later, his life's work apparently complete. It's kind of fitting that he probably wound up getting eaten by his favorite animal.
Something that Europeans and their descendants do that you might not realize seems downright bizarre to the rest of the world is that we like to drink cool glasses of that white stuff that comes out from under a cow. That's because most of the non-white population of the world -- 50 percent of Mediterraneans, 95 percent of Asians, and close to 100 percent of Native Americans -- are lactose intolerant. On the other hand, 90 percent of Europeans can drink milk just fine. So why whitey? Simply, early Europeans spent more time around cows.
David De Lossy/Photodisc/Getty Images
"I consider myself more a citizen of the world, thank you."
Humans, like every other mammal, were never designed to drink milk past infancy. Normal people (and considering the global statistics, it's the lactose intolerant who are the normal people) lose the ability to digest milk at around 5 years old. That's when we stop producing the enzyme lactase, which breaks down the milk sugars known as lactose. Without that, the lactose in milk just goes straight to our colon and reinvents itself as the Hershey squirts.
James Woodson/Photodisc/Getty Images
"In retrospect, this was way too much to do for a Klondike bar."
But after white Europeans and cultures around the Middle East domesticated cattle around 7,500 years ago, they started dabbling in drinking their milk. Those few who were able to tolerate it had an evolutionary advantage, having access to an abundant new source of protein and vitamin D. Since those who drank their milk grew big and strong, the ability to digest it spread around cattle farming communities until most people who spent a lot of time around cows grew to enjoy it without running to whatever passed for a bathroom back then.
"You actually dug a hole? You fucking snob."
For the rest of the world who preferred to obtain their nutrition in ways that didn't involve sucking on a cow's tits, their lactose intolerance remained just as it was. So if you've enjoyed some cheese recently, you know who to thank.
Because of their willingness to bite human and animal alike, fleas are extremely good at spreading disease. Countless human deaths can be attributed to their two most lethal gifts, the Black Death and smallpox. But here's the kicker -- by infecting us with these horrors back in a more classical period of history, fleas helped a bunch of us develop an immunity to HIV, and in doing so might help us find a cure for good.
Larry Busacca/Getty Images Entertainment/Getty Images
"All in a day's work."
HIV is a virus that destroys the immune system by infiltrating immune cells, which it can only do by going through a very specific opening in the cell wall, kind of like how Luke blew up the Death Star. Once all your body's Death Stars have been destroyed, you have the disease known as AIDS, which means that you have no immune system, and that's really bad. Really bad.
What's this got to do with fleas? Well, it turns out that the Black Death and smallpox infiltrate your cells in the exact same way. Back when these diseases ravaged the globe and killed almost everyone, there were a few people who, through random chance, had a genetic immunity (i.e., their little Vaders remembered to shut off the damn exhaust ports). Eliminating vast numbers of people who weren't immune allowed the resistance to spread through natural selection -- which, incidentally, also made them resistant to HIV. That's why today 10 to 18 percent of humans of European descent are either immune or resistant to HIV.
Carl Zimmer, via Berkeley.edu
Probably not you, though, so keep wearing those condoms, please.
The discovery of this mutation has led researchers to the creation of an antiviral medication called maraviroc and is helping them create the first ever HIV cure. So thanks, fleas; your murderous, infection-spreading lifestyle might just cure one of the worst human diseases ever.
Related Reading: You know what WOULD'VE changed the world, but never got the chance? The Gospel of Eve. Surprising things can have a big impact on human evolution: some scientists suspect Autism had a huge impact on the history of science and technology. Even prison is no barrier to changing the world.