Welcome to brain Stuff production of I Heart Radio. Hey brain Stuff, Lauren Bolga bam here. If you, presumably a human, spent the entire winter snoozing in bed, it's very unlikely that you'd be able to pop out your front door on the first balmy day of spring and run of five K. That's because our muscles have some very specific rules, and one of them is use it or lose it.
It makes sense, right Working a muscle lets our body know what's expected of it, So a human muscle develops pretty much exclusively through regular use and good nutritional intake. This is not the case for all animals, however. Take the thirteen lined ground squirrel, a native to the grasslands
and prairies of the North American Midwest. This little ground dweller hibernates in the winter, but like most winter sleeping mammals, it wakes up in the spring ready to return to hunting down prey, in this case, grasshoppers, right away, no training period necessary. A study published digitally in January two and the journal Science found that the thirteen lined ground squirrel is able to build some muscle even when it's not getting exercise or taking in nutrients. With the help
of a special friend, it's gut bacteria. Researchers in previous studies had noticed that the fat stores the hibernating ground squirrels industriously built up during the summer months began to decline sharply in February, and by the time they shuffled out of their burrows in April, they had lost about forty of their body weight from the autumn before, and the squirrels slept soundly and their body temperatures plummeted to match that of their chilly little burrows, their metabolism dropping
to around one percent of what it was in the summer months. However, toward the end of the winter, their leg muscles began to build new tissue. The study in the journal Science set out to discover the mechanism to allow animals that have been cut off from nutrients and movement for several months to still build muscle. The scientists have known for some time that there are ways for a body to create the nutrients needed to create muscle.
It's sometimes seen in cattle and other ruminant animals. The process is called urea nitrogen salvage, and it allows the body to retain nitrogen that would otherwise be sent out into the world in the form of urine, and nitrogen is essential to making protein, which is essential to building muscle. However, this process requires something else, an enzyme called urias, which
animals cannot produce, but certain bacteria can. The researchers learned that in order to find nitrogen to make protein and build enough muscles so they're behind legs aren't a pair of spaghetti noodles after a long winter's nap, the ground squirrels rely on specific gut bacteria. The bacteria make the urias that helped the squirrels mind the urea in their bodies for nitrogen. The bike grobes benefit too, by using
the resulting nitrogen to build proteins that they need. If hearing this makes you interested in whether humans might be able to build muscle without eating or working out, it turns out that we do have the ability, with the help of our gut bacteria, to recycle a small amount of urea nitrogen. The researchers think this discovery might have therapeutic applications to help people stuck in bed due to an illness or injury, or to help astronauts retain muscle mass.
While hanging out in space. Today's episode is based on the article Squirrels get jacked during Hibernation No Weights Needed on how stuffworks dot Com, written by Jesslin Shields. Brain Stuff is production of I Heart Radio in partnership with how stuff Works dot Com and is produced by Tyler Klang and Ramsey Young. For more podcasts my heart Radio, visit the heart Radio app, Apple podcast, or wherever you listen to your favorite shows. H