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Danielle Dufault via Smith et. al, Nature (2015)
Danielle Dufault via Smith et. al, Nature (2015)

It Took Scientists Almost 40 Years to Figure Out What Part of This Animal Is the Head

Danielle Dufault via Smith et. al, Nature (2015)
Danielle Dufault via Smith et. al, Nature (2015)

Millions of years ago, very different creatures roamed the earth—some so foreign to the modern world that scientists can’t even figure out how they would have stood up, much less which part of them was the head. Such is the case with Hallucigenia, a kind of spiky, tubular worm-creature that lived some 508 million years ago. A new study in Nature reveals where exactly the ancient animal’s head would have been—and points out its eyes for the first time. 

The blob on the right of the image above is not a head, but decay fluids (Df). The head is on the left. Image Credit: Smith et. al, Nature (2015)

First discovered in the Burgess Shale fossil field in Canada in 1977, it took almost 15 years for scientists to figure out how the sea creature stood up. The scientist who unearthed the fossil of a long, tubular body with seven pairs of spines and seven pairs of tentacles initially thought it walked along the ocean floor on its spines (using them like stilts) and used the tentacles to grab food. In 1991, further research revealed that the initial hypothesis was upside down: the tentacles were legs, and the spikes were located on its back for defense. At the end of its legs were claws. 

Watch this scientific illustration of Hallucigenia, and try not to laugh too hard imagining this thing walking toward you: 

But was the blobby appendage (the right side of the second fossil image above) located on one end of the body its head, or its butt? Admittedly, when looking at a flattened outline of the animal millions of years after its demise, it’s pretty hard to tell. Based on new analysis of specimens, Cambridge’s Martin Smith and Jean-Bernard Caron of the Royal Ontario Museum argue that the head is, in fact, at the opposite end from the blobby part, shown in fossil images, which was once thought to be the head. 

The head is on the left (b) in the image above. Image Credit: Smith et. al, Nature (2015)


Under an electron microscope, the researchers were able to identify a mouth and two clear dark spots that they hypothesize are remnants of the creature’s eyes. The mouth had a ring of spines around it to help it vacuum up food, and teeth in its throat to move the food into its gut. The legs had no joints, and it probably moved like a starfish, through pressurized fluid.

It looks like a cross between a dinosaur, a centipede, and a sea anemone. 

[h/t: Phenomena

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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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