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Dolphin Research Center, Grassy Key

How Do Dolphins Sleep Without Drowning?

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Dolphin Research Center, Grassy Key

Having to come to the surface regularly for oxygen makes dolphins great for reliable viewing. But doesn't it sound a little exhausting? As humans understand it, sleep tends to involve a level of unconsciousness that would seem dangerous to aquatic mammals. We reached out to the Dolphin Research Center in Florida to find out how they're able to sleep without drowning.

Senior Education Instructor/Handler Noelle Belden explains that first you have to understand that dolphins are conscious breathers—each breath is an active decision to swim to the surface and open their blowhole, rather than part of a constant "automatic" process like what humans have.

So that explains how they keep from drowning, but their sleep adaptation is more than a matter of holding their breath for a really long time.

Sleep Time

First of all, dolphins don't sleep in one long chunk like humans or other mammals. Instead, they take 15 to 20 minute naps throughout the day and night. But the biggest factor in dolphin sleep is their brain doesn't rest all at once like humans' do. "Scientists have discovered that instead of 'falling asleep' and entering an unconscious state like humans, a dolphin rests one hemisphere of its brain at a time," Belden explains. "So while one hemisphere is resting, the other is still active so that the dolphin can be sure to open its blowhole above the water."

Whichever brain hemisphere is active, the opposite eye will remain open. This is good for both swimming to the surface to breathe and for keeping a look out for predators. As Belden puts it, "Dolphins literally sleep with one eye open."

It's impossible to know what sleeping with just half your brain at a time would feel like, and dolphins can't exactly explain it to us. But Belden says that scientists speculate it might be sort of like daydreaming or meditating.

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Animals
Plagued with Rodents, Members of the UK Parliament Demand a Cat
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iStock

Members of the United Kingdom’s Parliament want a cat, but not just for office cuddles: As The Telegraph reports, the Palace of Westminster—the meeting place of Parliament’s two houses, the House of Commons and the House of Lords—is overrun with vermin, and officials have had enough. They think an in-house feline would keep the rodents at bay and defray skyrocketing pest control costs.

Taxpayers in the UK recently had to bear the brunt of a $167,000 pest control bill after palace maintenance projects and office renovations disturbed mice and moths from their slumber. The bill—which was nearly one-third higher than the previous year’s—covered the cost of a full-time pest control technician and 1700 bait stations. That said, some Members of Parliament (MPs) think their problem could be solved the old-fashioned way: by deploying a talented mouser.

MP Penny Mordaunt tried taking matters into her own hands by bringing four cats—including her own pet kitty, Titania—to work. (“A great believer in credible deterrence, I’m applying the principle to the lower ministerial corridor mouse problem,” she tweeted.) This solution didn’t last long, however, as health and safety officials banned the cats from Parliament.

While cats aren’t allowed in Parliament, other government offices reportedly have in-house felines. And now, MPs—who are sick of mice getting into their food, running across desks, and scurrying around in the tearoom—are petitioning for the same luxury.

"This is so UNFAIR,” MP Stella Creasy said recently, according to The Telegraph. “When does Parliament get its own cats? We’ve got loads of mice (and some rats!) after all!" Plus, Creasy points out, a cat in Parliament is “YouTube gold in waiting!"

Animal charity Battersea Dogs & Cats Home wants to help, and says it’s been trying to convince Parliament to adopt a cat since 2014. "Battersea has over 130 years [experience] in re-homing rescue cats, and was the first choice for Downing Street, the Foreign and Commonwealth Office, and the Cabinet Office when they sought our mousers to help with their own rogue rodents,” charity head Lindsey Quinlan said in a statement quoted by The Telegraph. “We'd be more than happy to help the Houses of Parliament recruit their own chief mousers to eliminate their pest problem and restore order in the historic corridors of power."

As of now, only assistance and security dogs are allowed on palace premises—but considering that MPs spotted 217 mice alone in the first six months of 2017 alone, top brass may have to reconsider their rules and give elected officials purr-mission to get their own feline office companions.

[h/t The Telegraph]

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Gray, George Robert; Hullmandel & Walton; Hullmandel, Charles Joseph; Mitchell, D. W / Public Doman
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Animals
DNA Tests Show ‘Extinct’ Penguin Species Never Existed
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Gray, George Robert; Hullmandel & Walton; Hullmandel, Charles Joseph; Mitchell, D. W / Public Doman

Science is a self-correcting process, ever in flux. Accepted hypotheses are overturned in the face of new information. The world isn’t flat after all. Disease isn’t caused by demons or wickedness. And that Hunter Island penguin? Yeah, apparently that was just a figment of our imaginations. Researchers writing in the Zoological Journal of the Linnean Society say the remains of one supposed species are in fact a “jumbled mixture” of bones from three extant species.

The bones were unearthed in the 1980s during the excavation of a prehistoric trash heap on Tasmania’s Hunter Island. Two scientists named Tets and O’Connor argued that the remains were different enough from other penguins to constitute their own genus and species, one which must have died out during the Holocene epoch. The proud potential penguin parents dubbed the apparently extinct bird Tasidyptes hunterivan, and that was that.

Except that this is science, where no story is ever really over. Other biologists were not satisfied with the evidence Tets and O’Connor presented. There were only four bones, and they all bore some resemblance to species that exist today. Fortunately, in 2017, we’ve got ways of making fossils talk. A research team led by Tess Cole of the University of Otago used DNA barcoding to examine the genetic code of each of the four bones.

“It was a fun and unexpected story,” Cole said in a statement, “because we show that Tasmania’s ‘extinct' penguin is not actually an extinct or unique penguin at all.”

Snares penguins dive into the water.
Snares penguins (Eudyptes robustus).
Brocken Inaglory, Wikimedia Commons // CC BY-SA 3.0

The bones were “a jumbled mixture of three living penguin species, from two genera": the Fiordland crested penguin or Tawaki (Eudyptes pachyrhynchus) and the Snares crested penguin (Eudyptes robustus), both of New Zealand, and the Australian little fairy penguin (Eudyptula novaehollandiae).

“This study shows how useful ancient DNA testing can be,” Cole said. “Not only does it help us identify new but extinct species, but it can help us rule out previously postulated species which did not exist, as in this case.”

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