WEBVTT - BrainStuff Classics: How Do Cold-Blooded Animals Survive the Winter?

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<v Speaker 1>Welcome to Brainstuff, a production of iHeartRadio.

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<v Speaker 2>Hey brain Stuff, Lauren Vogel Bomb here with a classic

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<v Speaker 2>episode from our archives. But with the weather turning colder

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<v Speaker 2>here in the Northern Hemisphere, I was thinking about all

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<v Speaker 2>of the cold blooded critters out there that depend on

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<v Speaker 2>sunlight and warm temperatures to keep their bodies going. Here

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<v Speaker 2>are some of the ways that they survive the winter.

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<v Speaker 1>Hey brain Stuff, I'm Lauren Vogelbomb, and you and I

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<v Speaker 1>can complain about seasonal chills all we want, but at

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<v Speaker 1>the end of the day, we're basically walking furnaces. Humans

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<v Speaker 1>are endotherms, meaning that our bodies produce heat internally. We're

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<v Speaker 1>also able to maintain a body temperature that stays more

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<v Speaker 1>or less constant, so we should count our blessings. Not

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<v Speaker 1>all animals have these physiological advantages. Apart from a handful

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<v Speaker 1>of species like the monstrously big leather back sea turtle,

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<v Speaker 1>very few reptiles or amphibians are able to keep their

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<v Speaker 1>bodies at a constant temperature, and since they can't warm

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<v Speaker 1>themselves up, these creatures must extract heat from their environment.

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<v Speaker 1>But what happens when that environment gets colder? Out of

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<v Speaker 1>frogs snakes and turtles make it through the winter months

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<v Speaker 1>in places that see blankets of snow, ice over lakes,

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<v Speaker 1>and sub freezing temperatures year after year. A lot of

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<v Speaker 1>reptiles and amphibians undergo periods of extreme seasonal inactivity. When

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<v Speaker 1>the weather gets colder. They may experience decreased heart rates,

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<v Speaker 1>slowed metabolisms, and lower overall body temperatures. Scientists disagree over

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<v Speaker 1>what to call this state. Everyone accepts that it's some

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<v Speaker 1>kind of dormancy, but while some experts classify it as hibernation,

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<v Speaker 1>others refer to it as brumation. Dormant snakes generally hold

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<v Speaker 1>themselves up in winter dens. These shelters may take the

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<v Speaker 1>form of an abandoned rodent burrow, an exposed crevice on

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<v Speaker 1>a rock face, or some naturally occurring hole underneath a tree.

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<v Speaker 1>Various snakes have also been known to turn household basements

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<v Speaker 1>or garages into winter lodges in seasonally cold areas like

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<v Speaker 1>Canada and the northern United States. Snakes must choose their

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<v Speaker 1>dens with care. Ideally, a winter hangout spot will descend

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<v Speaker 1>below the local frost line, the maximum depth beneath the

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<v Speaker 1>ground at which soil freezes. Hiding out underground is the

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<v Speaker 1>survival strategy of choice for lots of tortoises and turtles

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<v Speaker 1>as well. Some species, such as the gopher tortoise, dig

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<v Speaker 1>their own burrows, but it's not uncommon to find to

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<v Speaker 1>the shelled reptiles occupying pre dug unoccupied rodent holes. Now

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<v Speaker 1>a hibernating black bear can sleep for more than one

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<v Speaker 1>hundred days straight without consuming any food or water. Reptiles

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<v Speaker 1>tend to be more active during hibernation or breamation. When

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<v Speaker 1>a midwinter warm spell comes along, they'll use it as

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<v Speaker 1>an opportunity to crawl up to the surface, bask in

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<v Speaker 1>the sunlight for a little while, and maybe grab a

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<v Speaker 1>quick drink. Reptiles are perceived as loners, a reputation that

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<v Speaker 1>isn't entirely deserved. Consider the Eastern diamondback rattler, who doesn't

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<v Speaker 1>seem to mind collaborating with gopher tortoises. Members of both

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<v Speaker 1>species will sometimes go dormant together inside the same burrow. Likewise,

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<v Speaker 1>snakes often share their dens with other snakes. Garter snakes

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<v Speaker 1>are famous for hibernating in huge groups that may consist

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<v Speaker 1>of hundreds or even thousands of individuals. One Canadian den

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<v Speaker 1>reportedly contained no fewer than eight thousand snakes. Indiana Jones

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<v Speaker 1>and other videophiles will want to keep their distance as

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<v Speaker 1>snakes go. Garters are remarkably cold tolerant. One species can

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<v Speaker 1>even survive the unbelievable experience of having forty percent of

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<v Speaker 1>the liquid water inside its body freeze solid, but only

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<v Speaker 1>if it's allowed to thaw out after a few hours.

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<v Speaker 1>But the wood frog takes freeze tolerance to a whole

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<v Speaker 1>new level. A North American native, this cold weather warrior

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<v Speaker 1>has the distinction of being the only amphibian in the

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<v Speaker 1>Western hemisphere whose range extends into the Arctic Circle. Every autumn,

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<v Speaker 1>wood frogs bury themselves under a thin blanket of leaf

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<v Speaker 1>litter on the forest floor. There they will remain dormant

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<v Speaker 1>for up to eight months. In the process, the heart

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<v Speaker 1>temporarily stops beating and the frogs enter a state of

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<v Speaker 1>suspended animation. Left to the mercy of the elements. The

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<v Speaker 1>amphibians freeze at temperate and polar latitudes. Fortunately, the liver

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<v Speaker 1>pumps loads of glucose into the bloodstream, while urine is

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<v Speaker 1>retained than the body. All that helps keep the cells

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<v Speaker 1>from drying out, which is what would normally happen during

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<v Speaker 1>the freezing process. Therefore, a full sixty five percent of

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<v Speaker 1>all the water in a wood frog's body can become

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<v Speaker 1>frozen and the amphibian will still live to rib it

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<v Speaker 1>another day. Moreover, the frog may be kept frozen at

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<v Speaker 1>negative eighteen degrees celsius or about zero degrees fahrenheit, for

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<v Speaker 1>as long as two hundred and eighteen days. Another example

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<v Speaker 1>of this cool survival strategy can be found in far

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<v Speaker 1>North Russia. The Siberian salamander lives in areas that get

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<v Speaker 1>temperatures of negative fifty degrees celsius that's negative fifty eight

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<v Speaker 1>fahrenheit or lower. To stay alive, it hibernates underneath logs, vegetation,

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<v Speaker 1>and snowbanks. A compound in their bloodstream keeps the critters

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<v Speaker 1>alive when the majority of its body water turns to ice.

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<v Speaker 1>Terrestrial amphibians with poor digging skills, like the wood frog,

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<v Speaker 1>tend to either hibernate in pre existing burrows or fine

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<v Speaker 1>shelter at ground level. Good burrowers, such as the American

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<v Speaker 1>toad and spotted salamander, proactive dig winter holes from themselves

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<v Speaker 1>that extend below the frost line. For aquatically inclined amphibians,

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<v Speaker 1>there's another option. Bullfrogs are lake and pond denizens who

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<v Speaker 1>find oxygen rich bodies of water and spend their winters

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<v Speaker 1>imprisoned under the surface of ice that forms there. Painted

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<v Speaker 1>turtles employ a similar strategy. Reptiles generally use their lungs

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<v Speaker 1>to breathe, but some semi aquatic turtles can also absorb

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<v Speaker 1>water born oxygen through their skin overwintering. Painted turtles do

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<v Speaker 1>this extremely well, Plus they can lower their metabolic rates

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<v Speaker 1>to the tune of ninety five to ninety nine percent

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<v Speaker 1>each winter. That's how they stay alive beneath thick sheets

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<v Speaker 1>of lake ice for months on end. Sometimes you can

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<v Speaker 1>even see them swimming around under the frozen barriers. But

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<v Speaker 1>why go through the hassle of skin breathing when you

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<v Speaker 1>can turn your snout into a snarkel. In January of

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<v Speaker 1>twenty eighteen, the Internet was greatly amused by some North

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<v Speaker 1>Carolina alligators whose noses were seen poking up out of

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<v Speaker 1>a frozen pond. Gators can't survive being trapped in icy

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<v Speaker 1>water for much longer than a week or so. For

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<v Speaker 1>long term winter lodgings, they construct deep burrows out of

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<v Speaker 1>waterside mud. Today's episode is based on the article Weird

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<v Speaker 1>Ways Reptiles and Amphibians Survived the Winter on HowStuffWorks dot Com,

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<v Speaker 1>written by Mark Mancini.

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<v Speaker 2>A brain Stuff is production of ihart Radio in partnership

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<v Speaker 2>with how stuffworks dot Com, and it's produced by Tyler Klang.

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<v Speaker 2>Four more podcasts from my heart Radio, visit the iHeartRadio app,

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<v Speaker 2>Apple Podcasts, or wherever you listen to your favorite shows.