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These Baby Dinosaurs Were Born With Adult-Like Proportions

UA 9998 and friends. Image credit: D. Vital

Newly recovered fossils from a baby titanosaur suggest that the dinosaur would stay the same shape throughout its life, even as it grew to the size of a bus. These findings are reported in the journal Science.

Titanosaurs like Rapetosaurus krausei were the biggest land animals to ever walk the Earth. Multiple fossils from the 50-foot-long adults have been recovered and studied, but until recently we knew very little about hatchlings and juveniles. Then, paleontologists recovered the remains of an itsy-bitsy R. krausei from a rock formation in Madagascar. They found bones from the dinosaur’s hips, front legs, back legs, spine, and tail—all tiny. Of course, tiny is relative. The baby, which the researchers named UA 9998, appears to have been just a few weeks old, 88 pounds, and just over a foot tall when it died—and yet it was a mere speck compared with its mother.

Mom and baby, with shadowy human for scale. Image credit: Raul Martin and Kristina Curry Rogers

And the researchers did compare UA 9998 with adults like its mother. They cut slices from one of the baby dinosaur’s leg bones and examined them under the microscope. They also scanned all the bones using X-ray computed tomography.

Image credit: K. Curry Rogers, M. Whitney, M. D'Emic, and B. Bagley

The researchers found that aside from their diminutive scale, the baby’s bones were astonishingly like those of full-grown adults. Young though it was, the baby had sturdy bones and would have been independent enough to run around on its own. UA 9998 was proportioned and built exactly like an adult. Had it lived, it would have expanded. Compare that to, say, baby birds, or even human infants—floppy, dependent creatures that bear only a passing resemblance to their parents.

You might not guess it to look at them, but other dinosaurs like theropods and ornithischians had parent-offspring relationship more like ours. The sturdy little remains of UA 9998 suggest to paleontologists that titanosaur parents might have been a little less involved. 

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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
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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.
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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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