Speaker 1: Welcome to Brainstuff, a production of iHeartRadio. Hey brain Stuff,
Speaker 1: I'm Lauren vogelbaumb and this is a classic episode of
Speaker 1: the podcast. In this one, we get into the weird
Speaker 1: biology of how some air breathing mammals and reptiles managed
Speaker 1: to hold their breath underwater for minutes or even hours
Speaker 1: at a time. Hey brainstuff, Lauren Vogel bomb here you like,
Speaker 1: most humans can probably hold your breath for about two minutes,
Speaker 1: though in twenty sixteen, Guinness World Records clocked free diver
Speaker 1: a leash Seguravendrol of Barcelona, Spain, holding his breath for
Speaker 1: a little over twenty four minutes, which is of course
Speaker 1: completely wild. Humans aren't built for breath holding. We've got
Speaker 1: other priorities like world domination. If we had spent even
Speaker 1: a little more of our evolutionary history working on holding
Speaker 1: in air instead of making our brains giant and complex,
Speaker 1: we probably could survive without oxygen at least as long
Speaker 1: as the average beaver, which is fifteen minutes. But there
Speaker 1: are lots of air breathing animals that are built for
Speaker 1: breath holding. A sloth can hold its breath for a
Speaker 1: wapping forty minutes. Because it's able to decrease its heart
Speaker 1: rate to about a third of the normal. A sleeping
Speaker 1: sea turtle can hold its breath for up to seven
Speaker 1: hours at a time. A loggerhead turtles often forage underwater
Speaker 1: for around forty minutes in one go, but one study
Speaker 1: of loggerhead activity found that males can voluntarily sustain themselves
Speaker 1: on one breath or sometimes a quick charge up of
Speaker 1: several successive breaths, for around ten hours. One female was
Speaker 1: observed going as long as twenty hours. Some turtles can
Speaker 1: spend all winter long at the bottom of a frozen
Speaker 1: lake in deep hibernation, not using their lungs at all.
Speaker 1: The turtle's secret is that during this period of almost
Speaker 1: complete systems shut down, it does take in a tiny
Speaker 1: bit of oxygen by breathing through its highly vascularized cloaca.
Speaker 1: The kloaca being a single organ found in reptiles, birds, amphibians,
Speaker 1: and even some mammals that serves as the animals exit
Speaker 1: for its u urinary tract and digestive tract, and that's
Speaker 1: also the opening for their reproductive tract. Yes, they pee, poop,
Speaker 1: and have sex with this single organ in turtles with
Speaker 1: chloacal respiration. They can also draw water up into their
Speaker 1: kloaca and absorb oxygen from it, then flush it back out. Turtles, however,
Speaker 1: are ectotherms animals that rely on outside sources for heat.
Speaker 1: It's much easier for ectotherms to go without oxygen than endotherms.
Speaker 1: Like US mammals, we use a lot of oxygen keeping
Speaker 1: our systems running hot, which is why marine mammals like whales, seals,
Speaker 1: and otters are so impressive. They can pull off unbelievably
Speaker 1: long deep dives in order to hunt for food. Take
Speaker 1: Coovi's beaked whale, the deepest diving of all marine mammals,
Speaker 1: and the one scientists think holds the record for the
Speaker 1: endotherm that's achieved the longest breath holding session. These midsized
Speaker 1: whales can dive around ten thousand feet that's about three
Speaker 1: thousand meters, hunting for squid and other deep sea goodies,
Speaker 1: and they can hold their breath for an average of
Speaker 1: sixty seven minutes, with one record dive that lasted one
Speaker 1: hundred and thirty eight minutes before a Coovi's beaked whale
Speaker 1: broke the previous record. A Northern elephant seal was the
Speaker 1: gold medalist caught holding its breath at one hundred and
Speaker 1: nineteen minutes. A sperm whale now comes in third place
Speaker 1: at ninety minutes. That's a long time to go without
Speaker 1: oxygen when you've got an expansive mammalian metabolism to keep up.
Speaker 1: But lots of marine and aquatic mammals make it work
Speaker 1: by slowing their heart rates and redirecting blood away from
Speaker 1: their extremities into their brains, hearts, and muscles. They even
Speaker 1: have special oxygen binding proteins in their muscles that allow
Speaker 1: them to store more oxygen than us land lovers. Today's
Speaker 1: episode is based on the article what animal can hold
Speaker 1: express the longest on houstufforks dot com written by Jesslinshields.
Speaker 1: Brain Stuff is production by Heart Radio in partnership with
Speaker 1: houstuffworks dot Com and is produced by Tyler Glang. Four
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