WEBVTT - How Do Some Squirrels Gain Muscle During Hibernation?

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<v Speaker 1>Welcome to brain Stuff production of I Heart Radio. Hey

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<v Speaker 1>brain Stuff, Lauren Bolga bam here. If you, presumably a human,

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<v Speaker 1>spent the entire winter snoozing in bed, it's very unlikely

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<v Speaker 1>that you'd be able to pop out your front door

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<v Speaker 1>on the first balmy day of spring and run of

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<v Speaker 1>five K. That's because our muscles have some very specific rules,

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<v Speaker 1>and one of them is use it or lose it.

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<v Speaker 1>It makes sense, right Working a muscle lets our body

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<v Speaker 1>know what's expected of it, So a human muscle develops

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<v Speaker 1>pretty much exclusively through regular use and good nutritional intake.

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<v Speaker 1>This is not the case for all animals, however. Take

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<v Speaker 1>the thirteen lined ground squirrel, a native to the grasslands

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<v Speaker 1>and prairies of the North American Midwest. This little ground

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<v Speaker 1>dweller hibernates in the winter, but like most winter sleeping mammals,

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<v Speaker 1>it wakes up in the spring ready to return to

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<v Speaker 1>hunting down prey, in this case, grasshoppers, right away, no

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<v Speaker 1>training period necessary. A study published digitally in January two

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<v Speaker 1>and the journal Science found that the thirteen lined ground

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<v Speaker 1>squirrel is able to build some muscle even when it's

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<v Speaker 1>not getting exercise or taking in nutrients. With the help

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<v Speaker 1>of a special friend, it's gut bacteria. Researchers in previous

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<v Speaker 1>studies had noticed that the fat stores the hibernating ground

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<v Speaker 1>squirrels industriously built up during the summer months began to

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<v Speaker 1>decline sharply in February, and by the time they shuffled

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<v Speaker 1>out of their burrows in April, they had lost about

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<v Speaker 1>forty of their body weight from the autumn before, and

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<v Speaker 1>the squirrels slept soundly and their body temperatures plummeted to

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<v Speaker 1>match that of their chilly little burrows, their metabolism dropping

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<v Speaker 1>to around one percent of what it was in the

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<v Speaker 1>summer months. However, toward the end of the winter, their

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<v Speaker 1>leg muscles began to build new tissue. The study in

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<v Speaker 1>the journal Science set out to discover the mechanism to

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<v Speaker 1>allow animals that have been cut off from nutrients and

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<v Speaker 1>movement for several months to still build muscle. The scientists

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<v Speaker 1>have known for some time that there are ways for

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<v Speaker 1>a body to create the nutrients needed to create muscle.

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<v Speaker 1>It's sometimes seen in cattle and other ruminant animals. The

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<v Speaker 1>process is called urea nitrogen salvage, and it allows the

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<v Speaker 1>body to retain nitrogen that would otherwise be sent out

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<v Speaker 1>into the world in the form of urine, and nitrogen

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<v Speaker 1>is essential to making protein, which is essential to building muscle. However,

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<v Speaker 1>this process requires something else, an enzyme called urias, which

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<v Speaker 1>animals cannot produce, but certain bacteria can. The researchers learned

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<v Speaker 1>that in order to find nitrogen to make protein and

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<v Speaker 1>build enough muscles so they're behind legs aren't a pair

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<v Speaker 1>of spaghetti noodles after a long winter's nap, the ground

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<v Speaker 1>squirrels rely on specific gut bacteria. The bacteria make the

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<v Speaker 1>urias that helped the squirrels mind the urea in their

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<v Speaker 1>bodies for nitrogen. The bike grobes benefit too, by using

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<v Speaker 1>the resulting nitrogen to build proteins that they need. If

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<v Speaker 1>hearing this makes you interested in whether humans might be

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<v Speaker 1>able to build muscle without eating or working out, it

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<v Speaker 1>turns out that we do have the ability, with the

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<v Speaker 1>help of our gut bacteria, to recycle a small amount

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<v Speaker 1>of urea nitrogen. The researchers think this discovery might have

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<v Speaker 1>therapeutic applications to help people stuck in bed due to

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<v Speaker 1>an illness or injury, or to help astronauts retain muscle mass.

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<v Speaker 1>While hanging out in space. Today's episode is based on

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<v Speaker 1>the article Squirrels get jacked during Hibernation No Weights Needed

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<v Speaker 1>on how stuffworks dot Com, written by Jesslin Shields. Brain

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<v Speaker 1>Stuff is production of I Heart Radio in partnership with

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<v Speaker 1>how stuff Works dot Com and is produced by Tyler

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<v Speaker 1>Klang and Ramsey Young. For more podcasts my heart Radio,

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