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This week on SciShow News: Animals! New research has found how dogs actually listen to us in more complex ways than you probably thought, and also figured out how a kind of pufferfish gets its puff up.

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Sources:
http://www.eurekalert.org/jrnls/cell/pages/pdf/currentbiology/curbio11551.pdf
http://news.sciencemag.org/biology/2014/11/dogs-really-do-listen-us?utm_campaign=email-news-latest&utm_source=eloqua
http://discovermagazine.com/1997/sep/howthepufferfish1226
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Dogs! I love 'em, they're probably the internet's second favorite animal, just slightly behind cats and ahead of honey badgers and foxes and angry emus. And if there's a dog with you right now watching it turns out that he or she might me listening to me pretty much in the same way that you are. Hi dog! 

When you listen to me talk - I'm talking to the human now, not the dog any more - when you listen to me talk you're hearing more than just the words that are coming out of my mouth. You're also hearing all the tones of my voice and that's giving you clues to my gender and clues to my emotional state - am I happy or sad or excited? All these are tones are called prosodic cues. They involve the elements of speech that are less about meaning and more about rhythm and stress and intonation. Phonetic cues meanwhile are what help us understand actual words and the meanings behind them.

Now studies have already found that dogs process things like rhythm and intonation when they listen to other dogs, and this week scientists have announced that they do the same thing when listening to us.

It's really cool how they did it: biologists at the University of Sussex tested dogs' listening abilities by analyzing how more than 200 canines responded to pre-recorded samples of human speech. They had each pup stand between a pair of speakers and then played recordings of different people saying different phrases, some with a lot of prosodic cues while others were read in an atonal almost robotic voice. The scientists predicted that the dogs would probably turn their heads to the left speaker when they heard one type of voice and to the right speaker when they heard the other. Now that's weird, but it's because the more emotion-based prosodic cues are thought to be processed by the right hemisphere of the brain while the meaning-based phonetic cues are processed by the left hemisphere. So when a command like "come on then" was played in an atonal voice 80% of the dogs looked at the right speaker, suggesting that the command was registered in the left hemisphere of the brain, 'cause remember a sound heard in one ear is transmitted to the opposite side of the brain. But when the same phrase was said in the happy, expressive, human way the dogs looked at the left speaker, indicating that they were processing the prosodic cues on the right side of the brain, which is just how we do it! 

So, obviously your dog understands everything you say right? No. But it does suggest that there's a lot more information processing going on behind those adoring eyes and lolling tongue than you might think.

Now, your dog probably has its own adorable way of getting out of trouble when you get mad, but one of the coolest avoidance strategies of the animal kingdom belongs to another creature in the news this week: the pufferfish. There are more than 120 species of pufferfish around the world, mostly found in warm waters, and they're almost all as poisonous in real life as they are in Minecraft. But until now we weren't really sure how they performed their namesake trick - inflating their bodies to 3 or 4 times their normal size.

When a pufferfish sees a potential threat like a tiger shark or a scuba diver, they start quickly gulping up water. As they ingest that water their highly elastic stomach expands, nearly quadrupling their body's volume. Most scientists thought the puffers managed to hold this water by basically doing what they look like, they're holding their breath. That's because some studies have found that puffer's gill slits, actually called opercula valves, clamp shut when they're in full puff mode, suggesting that they have to stop breathing in order to hold the water inside. Which would be amazing if it were true because a puffer can stay inflated for 20 to 30 minutes.

But a new study of black-saddled pufferfish native to the Indian Ocean has found that there's something else going on here. Scientists from the James Cook University in Australia studied black-saddled puffers in special tanks called respirometers which could measure how quickly fish respire oxygen. Every 5 to 10 minutes the tank was flushed with oxygenated water; the biologists then measured how much oxygen was consumed between flushes to figure out how much the fish were breathing. 

They found that when inflated the puffers were using up to 5 times more oxygen than in their deflated state, and their gills were still moving. So the biologists now think that black-saddled puffers have a specialized sphincter in their esophagus which they can close to keep the water in their stomachs while allowing the gills to keep working.

The study also found that this amazing ability comes at a cost. It seems that getting and staying inflated is exhausting. The puffers breathed a lot harder when they were gulping water into their stomachs; so hard in fact that it took 5 and a half hours for their oxygen levels to return to normal.

So, if you see a puffer on your next snorkelling trip, just leave the poor guy alone. 

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