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Our Cheeseburgers Are Changing Ants’ Bodies

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If you happened to walk down Broadway in New York City in late May 2013, you may have seen something extraordinary: a man crawling over the sidewalks through garbage, occasionally stopping to suck up ants through a straw-like device called a pooter. This man was biologist Dr. Clint Penick, and he kept up this behavior for a week. “Not a single person asked me what I was doing,” Penick tells mental_floss. “I guess I wasn’t the weirdest thing they’d seen that day.”

Penick and his team at NC State collected 21 species of New York City ants to measure their stable isotopes and find out what the ants were eating. The researchers learned that some urban ant species are forgoing their usual diet of dead bugs in favor of Big Macs and milkshakes.

Everything we eat leaves its mark in our bodies in the form of stable isotopes. For example, corn—even in the form of corn oil, corn syrup, and corn-fed beef and chicken—is easy to spot. Animals that have eaten a lot of corn-based foods will have a much higher ratio of C13 to C12 isotopes than those that don’t. And let’s be clear: Americans are eating a lot of corn. A 2008 study measured stable isotopes in foods and drinks from Burger King, McDonalds, and Wendy’s meals all over America. They found corn in almost everything from Burger King and McDonald’s, and in every single item from Wendy’s.

Dr. Penick saw this as an opportunity. “You can take a hair sample from a human in New York City and one from someone in London and you can tell them apart based on their carbon isotopes and the corn in their diet,” he says. His team wondered if the same thing would work for ants.

The scientists were most interested in Tetramorium sp. E, the species commonly known as the pavement or picnic ant. Little is known about pavement ants other than their incredible adaptability, which has allowed them to set up shop in cities worldwide. “They’re like pigeons or rats,” says Dr. Penick.

The results were unsurprising, but quite clear: Pavement ants and most other species had stopped scavenging dead insects and had started scavenging our fallen french fries. “The chemical makeup of their bodies changed,” Dr. Penick says. “They looked more like humans because they were eating the same foods.”

This is probably not great for the ants, but it could be great news for us. In a paper published today in Proceedings of the Royal Society B, Penick and his colleagues write, “The average person living in a city will produce nearly half a metric ton of garbage this year, and of that, 15 percent will be food waste.” By gobbling up what we leave behind, ants are doing us a service. Just how much are they actually eating?

Naturally, scientists can tell us. In 2014, another team of researchers left weighed samples of hot dogs, cookies and potato chips on NYC sidewalks. After 24 hours, they weighed what was left, and the results were staggering: “We calculate that the arthropods on medians down the Broadway/West St. Corridor alone could consume more than 2100 pounds of discarded junk food, the equivalent of 60,000 hot dogs, every year—assuming they take a break in the winter.”

On the other hand, says Penick, the volume of our delicious trash is keeping the ants and their garbage-eating colleagues around. “If we weren’t dropping this food,” he said, “how many ants would be in our cities? How many pigeons? How many rats?”

“We don’t really think too much about what happens when we drop part of our lunch on the sidewalk,” he says, “but the cumulative effects of all of these actions of thousands of people every day can have a pretty significant impact on the species that live alongside us. When we consider a city as an ecosystem, it’s important to include humans and our actions.”

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Big Questions
What's the Difference Between Gophers and Groundhogs?
Gopher or groundhog? (If you chose gopher, you're correct.)
Gopher or groundhog? (If you chose gopher, you're correct.)
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Gophers and groundhogs. Groundhogs and gophers. They're both deceptively cuddly woodland rodents that scurry through underground tunnels and chow down on plants. But whether you're a nature nerd, a Golden Gophers football fan, or planning a pre-spring trip to Punxsutawney, Pennsylvania, you might want to know the difference between groundhogs and gophers.

Despite their similar appearances and burrowing habits, groundhogs and gophers don't have a whole lot in common—they don't even belong to the same family. For example, gophers belong to the family Geomyidae, a group that includes pocket gophers (sometimes referred to as "true" gophers), kangaroo rats, and pocket mice.

Groundhogs, meanwhile, are members of the Sciuridae (meaning shadow-tail) family and belong to the genus Marmota. Marmots are diurnal ground squirrels, Daniel Blumstein, a UCLA biologist and marmot expert, tells Mental Floss. "There are 15 species of marmot, and groundhogs are one of them," he explains.

Science aside, there are plenty of other visible differences between the two animals. Gophers, for example, have hairless tails, protruding yellow or brownish teeth, and fur-lined cheek pockets for storing food—all traits that make them different from groundhogs. The feet of gophers are often pink, while groundhogs have brown or black feet. And while the tiny gopher tends to weigh around two or so pounds, groundhogs can grow to around 13 pounds.

While both types of rodent eat mostly vegetation, gophers prefer roots and tubers (much to the dismay of gardeners trying to plant new specimens), while groundhogs like vegetation and fruits. This means that the former animals rarely emerge from their burrows, while the latter are more commonly seen out and about.

Groundhogs "have burrows underground they use for safety, and they hibernate in their burrows," Blumstein says. "They're active during the day above ground, eating a variety of plants and running back to their burrows to safety. If it's too hot, they'll go back into their burrow. If the weather gets crappy, they'll go back into their burrow during the day as well."

But that doesn't necessarily mean that gophers are the more reclusive of the two, as groundhogs famously hibernate during the winter. Gophers, on the other hand, remain active—and wreck lawns—year-round.

"What's really interesting is if you go to a place where there's gophers, in the spring, what you'll see are what is called eskers," or winding mounds of soil, Blumstein says [PDF]. "Basically, they dig all winter long through the earth, but then they tunnel through snow, and they leave dirt in these snow tunnels."

If all this rodent talk has you now thinking about woodchucks and other woodland creatures, know that groundhogs have plenty of nicknames, including "whistle-pig" and "woodchuck," while the only nicknames for gophers appear to be bitter monikers coined by Wisconsin Badgers fans.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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Animals
Watch Christmas Island’s Annual Crab Migration on Google Street View
Google
Google

Every year, the 45 million or so red crabs on the remote Australian territory of Christmas Island migrate en masse from their forest burrows down to the ocean to mate, and so the female crabs can release their eggs into the sea to hatch. The migration starts during the fall, and the number of crabs on the beach often peaks in December. This year, you don’t have to be on Christmas Island to witness the spectacular crustacean event, as New Atlas reports. You can see it on Google Street View.

Watching the sheer density of crabs scuttling across roads, boardwalks, and beaches is a rare visual treat. According to the Google blog, this year’s crabtacular finale is forecasted for December 16, and Parks Australia crab expert Alasdair Grigg will be there with the Street View Trekker to capture it. That is likely to be the day when crab populations on the beaches will be at their peak, giving you the best view of the action.

Crabs scuttle across the forest floor while a man with a Google Street View Trekker walks behind them.
Google

Google Street View is already a repository for a number of armchair travel experiences. You can digitally explore remote locations in Antarctica, recreations of ancient cities, and even the International Space Station. You can essentially see the whole world without ever logging off your computer.

Sadly, because Street View isn’t live, you won’t be able to see the migration as it happens. The image collection won’t be available until sometime in early 2018. But it’ll be worth the wait, we promise. For a sneak preview, watch Parks Australia’s video of the 2012 event here.

[h/t New Atlas]

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