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What’s the Difference Between a Mammoth and a Mastodon?

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The Woolly Mammoth (Mammuthus primigenius) and the American Mastodon (Mammut americanum) both roamed the North American wilderness until roughly 10,000 years BCE (although a few remarkable “dwarf mammoths” managed to hold out for a good while longer). But what exactly is it that sets them apart? (And yes, there were several other species of both Mammoth and Mastodon, but for simplicity’s sake, we’ll focus on the two most famous.)

Let’s start with a quick look at their family tree. The group of land mammals scientifically known as “proboscideans” contains living elephants and their ancient kin. In its heyday, this was a pretty diverse lot. Twenty-first century elephants are far more closely akin to mammoths than the relatively-primitive mastodons.

Want proof? Check out their teeth. Just like today’s tuskers, Mammoths tended to live in wide open plains, as demonstrated by their very elephant-like molars, each of which looked like a bony cheese-grater and was built to grind up tough grasses. Conversely, the word “Mastodon” literally means “nipple tooth." This is because the grooves in their chompers reminded some 18th Century paleontologists of human breasts. High-crowned teeth like this are better suited for mashing leaves and twigs, and, appropriately, Mastodon remains are usually found in forested environments. You can see the animals’ jaws compared side-by-side in this clip at the 0:26-mark:

Furthermore, as expert Daniel Fisher explained in the video above, Mammoths have curved tusks and high shoulders while Mastodons have straighter tusks and lower shoulders.

Thanks to a handful of frozen carcasses, genetic analyses have long-since confirmed the link between Mammoths and elephants. In fact, Mammuthus DNA has been so broadly studied that a Mammoth Genome Project is in the works.

Mastodons have had their admirers as well, including Thomas Jefferson himself, who actually stored a collection of their bones in the White House—though he did mistakenly believe that they were gigantic carnivores.

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Animals
This Octopus Species in Northern Australia Can Hunt on Dry Land
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YouTube

Most octopuses live in the ocean—but in northern Australia, a small, shallow-water species takes to land in search of food. Abdopus aculeatus is the only octopus that’s specially adapted to walk on dry ground. Using its long, sucker-lined arms, the slimy sea creature pulls itself along the shoreline as it searches tide pools for crabs.

Witness Abdopus aculeatus in action by watching BBC Earth’s video below.

[h/t BBC Earth]

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Weather Watch
Rising Temperatures Are Killing Off African Wild Dogs
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Over the last few decades, images of fluffy white harp seals, polar bears, and penguins have become shorthand for climate change's creeping destruction of our planet. But the poles aren't the only ecosystems in danger. A new study published in the Journal of Animal Ecology finds that rising temperatures near the equator are making it much harder for African wild dogs to survive.

"When people think about climate change affecting wildlife, they mostly think about polar bears," lead researcher Rosie Woodroffe of the Zoological Society of London told The Guardian. "But wild dogs are adapted to the heat—surely they'd be fine."

To find out, Woodroffe and her colleagues analyzed data from packs of African wild dogs (Lycaon pictus) in Kenya, Botswana, and Zimbabwe. The dog packs have been under scientist surveillance for years—some since the late 1980s—and at least one dog per pack is fitted with a radio collar.

The researchers overlaid information about local weather and temperature with data on the dogs' hunting habits, the size of each litter of pups, and how many pups from each litter survived.

These dogs are creatures of habit. Adults rise early and leave the den for a morning hunt. They range over their large territories, chasing antelopes. At midday, when the Sun is highest, they return to their pups with food. They may go out again in the evening as the temperature drops.

But like the polar bears' glaciers, the dogs' environment is gradually heating up. All three countries saw a temperature increase of about 1.8°F over the study period. This may not sound like much, but for the dogs, it was plenty. Between 1989 and 2012, the number of pups per litter in Botswana surviving to their first birthday dropped from 5.1 to 3.3. Dog packs in Zimbabwe saw a 14 percent decrease in pup survival; in Kenya, the rate declined by 31 percent.

"It's really scary," Woodroffe said.

"If you are an animal who makes your living by running around really fast, obviously you are going to get hot. But there are not enough hours in the day anymore that are cool enough to do that. It is possible that some of these big areas will become too hot for wild dogs to exist."

Woodroffe and her colleagues were not anticipating such clear-cut results. "It is shocking and surprising that even right on the equator these effects are being seen," she said. "It illustrates the global impact of climate change." 

[h/t The Guardian]

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