5 Unintentional Ways Humans Are Totally Changing Evolution

By:: E. Reid Ross; Eamon Lahiri; Sarah Philip; Tee Ngin Rui

April 06, 2019

5 Unintentional Ways Humans Are Totally Changing Evolution

If we've proven anything in the last seven nuclear meltdowns, nothing spurs evolution more than a bunch of rude humans wrecking the place up. That's why some critters have decided to skip the natural struggle altogether, and focus instead on finding ways to make it in the big city. Like ...

5 Bears Are Exploiting A Hunting Rule To Better Care For Their Cubs

Aside from trying to keep your stockpile of pic-a-nic baskets safe, there really isn't a good reason left to hunt bears. Nonetheless, shooting the big salmon suckers remains a popular pastime in Sweden, which apparently hasn't gotten Netflix yet. But there are a set of limits to the practice which change the ways bears are hunted, and which hunters should probably memorize. Because the bears certainly have.

One of the most important rules in bear hunting is never killing a mama bear still raising her cubs. Anytime a hunter sees a group of tiny bear brats following their target, they have to back off. And the bears, using their instinctual ability to sense legal loopholes, have adapted to this by caring for their cubs longer. Like, a whole year longer, which in bear years is the equivalent of guilting your 18-year-old into going to the nearby community college so they don't have to move out.

0.22 Mortality cause 0.20 Hunting 0.18 Other 0.16 0.14 0.12 0.10 0.08 0.06 0.04 0.02 0.00 Solitary Family group Adult female status — Van de Walle, Et. Al./Nature

Continue Reading Below

While this strategy does lessen breeding opportunities, that population dip is more than evened out by a stellar increase in the survival rates for both adult females and cubs. And the males? As absentee parents, they don't reap any benefits from walking around with a few adorable bullet shields. So unless they want to keep winding up as rugs on the floor, they should stop wandering off to get drunk on rotten berries and stay at home like a proper papa.

4 Lizards Are Developing Bigger Feet To Navigate Cities

Anole lizards are very good at adapting to new environments, and that includes man-made concrete jungles, where they are literally evolving stickier feet. A study of the Puerto Rican anole showed that compared to their hillbilly cousins, city-dwelling lizards had a predisposition for bigger feet (to cover more surface area) and longer lamellae, which are those sticky hairs lizards and Spider-Man use to hang from ceilings.

Thanks to this "urban evolution," the anole can now easily climb up straight walls and even glass windows. Even new generations raised by scientists in sterile conditions managed to keep their bigger and stickier feet, meaning that in less than a century, these lizards have changed their very genes to better emulate a Garfield Stuck On You.

3 Swallows Are Evolving Shorter Wings To Avoid Traffic

Each year, about 80 million American birds are turned into roadkill -- ironically while trying to eat roadkill themselves. You'd think that some of them would've figured out a way to keep from bouncing off license plates already. And you would think right.

Cliff swallows have spent generations making their nests in cliff-side crevices, hence the name. But in response to rapid urbanization, they decided to ditch their old breeding grounds in favor of some uptown real estate under highway bridges and overpasses. Sadly, as a result, a large number of Nebraskan cliff swallows have met their swift and brutal doom at the receiving end of a truck grill. But since the 1980s, the number of roadkill swallows has been taking a nosedive, despite the number of nests still growing by the year. What's their secret to surviving the killer city traffic? Making themselves more compact and sporty by reducing their wingspan.

According to a study by the University of Tulsa, the sharp decline in the number of deaths was matched by an equally rapid shrinking of the birds' wings. Having shorter wings means it's easier for the birds to take off faster and more vertically -- something that comes in pretty handy when an 18-wheeler is barreling toward you at 70 miles per hour. The change isn't even that impressive; only a few millimeters have been shaved off the wing in general, but that tiny difference is enough for countless swallows to beat the traffic with style.

2 Urban Spiders Have Evolved To Love Fluorescent Light

While living in Vienna in the '90s, arachnologist Astrid Heiling noticed that the spiders on her local pedestrian bridge preferred to hang out on the well-lit parts of the handrails, rather than in the dark nooks and crannies. Intrigued, Heiling started taking a spider-census, and found that they not only preferred the fluorescent lights, but craved them. Webs numbered well into the thousands, with many overlapping -- proving that even spiders can't escape urban crowding.

So why would these spiders renounce their allegiance to the darkness? Simple, because their prey like it too. City insects are drawn to nighttime lighting like a moth to a 150w LED bulb. As a result, the spiders whose ancestors tolerated the bright lights of the big city were able to catch up to four times more prey than their shadow-dwelling throwbacks. Anyway, that's why the future will bring us killer laser spider infestations.

1 Moths Are Evolving To Stay The Hell Away From Lamps

Moths and lamps have been inseparable since the days of Tesla and Edison, but their unnatural obsession for unnatural light hasn't exactly been good for their health. Luckily, it seems that some moth clans are finally figuring how to quit hitting the bulb and are getting high on life instead.

A study of urban moths in cities and towns across Switzerland and France has shown that moths are actually evolving to stay away from light in order to avoid being charred to death or getting gobbled up by savvy predators. But it takes a lot of wattage before that particular light bulb goes off in a moth's mind.

Scientists ran the experiment on moths they collected from both cities and villages, and found that specifically those exposed to constant overwhelming light pollution (i.e. city slickers) had an instinctual habit to avoid the light in favor of darkness. Meanwhile, their hillbilly brethren continued flocking to the fluorescent to get their fix. And thus starts the great moth culture gap.

E. Reid Ross has a couple books, Nature Is The Worst: 500 Reasons You'll Never Want To Go Outside Again and Canadabis: The Canadian Weed Reader, both available at Amazon and Barnes and Noble.

For more, check out 5 Animals Who Can't Hide Their Disdain For People:

The first-ever Cracked Podcast LIVE TOUR is coming to a city near (some of) you this spring! Tickets on sale now for Chicago IL (April 11th) and St. Paul MN (April 12th).

Follow us on Facebook. Because we said so.