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Cliff via Wikimedia Commons // CC BY 2.0
Cliff via Wikimedia Commons // CC BY 2.0

Human-Made Noise May Interfere with Panda Sex

Cliff via Wikimedia Commons // CC BY 2.0
Cliff via Wikimedia Commons // CC BY 2.0

Pandas are not the most motivated animals when it comes to sex. Their apparent disinterest in self-preservation has vexed even the most dogged conservationists for more than 50 years. Why, scientists have asked, won’t they just mate? Researchers think they may have found one reason: noise pollution. They published their findings in the journal Global Ecology and Conservation.

Sound is an essential element of panda sex. Unlike other bears, female pandas are spontaneous ovulators; that is, it happens when it happens, instead of being triggered by an external factor like sex or seasonal changes. But giant pandas are loners, which means it's unlikely that a male panda and a female panda will be in the same place when she starts ovulating. To find each other, they start yelling, and continue to do so even once they’re together. Each outburst could potentially contain a lot of important information about the noise-maker, including their location and their intention—but only if other pandas can hear and understand them.

While we know a lot about bears, we know very little about their hearing. There’s only one species whose hearing abilities have been quantified: polar bears. So conservation biologists at the San Diego Zoo decided to give their five pandas a hearing test.

“… The ability to discriminate between fine-scale differences in vocalizations is important for successful reproduction,” lead author Megan Owen said in a press statement, “and so, a thorough understanding of acoustic ecology is merited in order to estimate the potential for disturbance.”

For obvious reasons, this was a slightly complicated endeavor. First, the researchers had to construct a soundproof testing booth, which in this case meant gluing acoustic foam and plywood onto a transport crate. They outfitted the booth with microphones, speakers, a camera, colored lights, a camera, and a target.

The pandas were somewhat used to taking tests, so it wasn’t difficult for the zoo staff to train them in the booth. The test format played to their natural strength: not moving. The bears were taught to stay still until they heard a noise, at which point they would turn and put their noses against the target.

Once a bear was in the booth, the researchers played a series of noises that pandas might hear in the wild, including cubs crying and squawking and adults growling. As in hearing tests for humans, the sounds varied in pitch and volume.

The researchers found that the pandas had surprisingly sensitive hearing and were able to detect noises between 0.10 and 70.0 kHz—well into ultrasonic range. Their ears were as sharp, and, at some pitches, sharper, than polar bears’.

Wouldn't acute hearing be a good thing for a species that relies on sound to get busy? Yes and no. It’s great if pandas are the only noisemakers around. But as climate change reduces their habitat, even pandas on nature reserves are being pushed closer to people and all of our noisy business. The researchers say anthropogenic, or human-made noise, may drown out the sounds the pandas most need to hear.

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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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