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What's the Difference Between Seals and Sea Lions?

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There's a good reason seals and sea lions look so similar—they're both members of the pinniped taxonomic group, a name which refers in Latin to their "fin feet." Walruses are also a part of the clade but while their prominent tusks set them apart, seals and sea lions can be slightly harder to distinguish.

The easiest way to tell the two marine mammals apart is a matter of ears—or lack thereof. While sea lions have small ear flaps, seals have just tiny holes on the sides of their sleek, aquadynamic heads. This telltale sign is one of several adaptive differences based on slightly different lifestyles.

Seals are typically loners, who spend most of their life in the water. Their stubby front flipper-like feet and backward-facing hind flippers are little help on land, where they must wriggle about to move, but make them quick and agile underwater.

Meanwhile, sea lions are larger, louder and more social, often gathering in herds of up to 1500 individuals barking to each other. Accordingly, their feet are well-suited to lugging their several hundred pound bodies around rocky beaches with elongated fore flippers and hind flippers that are able to rotate forward.

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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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