Speaker 1: Welcome to Brainstuff, a production of iHeartRadio, Hey brain Stuff
Speaker 1: Lauren vogelbamb Here. Turtle is the common American English word
Speaker 1: for the three hundred and fifty sum species of reptiles
Speaker 1: known for their characteristic shells. Sometimes you might see, especially
Speaker 1: in British English, distinctions between land based tortoises, freshwater terrapins,
Speaker 1: and marine turtles. But today I'm talking about the whole
Speaker 1: mess of them using the word turtle. Okay, okay. They
Speaker 1: live in oceans, lakes, streams, forests, and deserts all over
Speaker 1: the world except Antarctica. They might be in a yard
Speaker 1: or pond near you, and those shells are amazing adaptations.
Speaker 1: The shape of a turtle shell depends on the species
Speaker 1: and the turtle's habitat. Most land dwelling turtles have a high,
Speaker 1: domed shell, which helps protect them from the jaws of predators,
Speaker 1: while most aquatic turtles have a more streamlined, flattened shell
Speaker 1: that lets them glide through the water. Turtle's shells are
Speaker 1: made up of two parts, the carapas, which is the
Speaker 1: upper half on the turtle's back, and the plastrin, which
Speaker 1: is the lower half under the turtle's belly. Structures called bridges,
Speaker 1: fasten the two together. The turtle sides. They're generally bony,
Speaker 1: but in soft shell turtles they're flexible. For the many
Speaker 1: species of turtles able to retract into their shells, a
Speaker 1: hinge joins the two halves together That allows the carapas
Speaker 1: and plastron to close tightly when the turtle draws itself in.
Speaker 1: Both the carapus and plastron are made of bone, including
Speaker 1: about fifty to sixty rib and backbones in the upper
Speaker 1: shell and a fusion of clavical and rib bones in
Speaker 1: the lower shell. On the outside of the bone, each
Speaker 1: shell half is covered in scoots, sometimes called shields, which
Speaker 1: are overlapping pieces of keratin the same substance as human fingernail.
Speaker 1: The scoots provide a protective coating. Most soft shelled species
Speaker 1: don't have scoots, but they do have a layer of tough,
Speaker 1: leathery skin. So a turtle's shell offers intricate skeletal protection.
Speaker 1: But can a turtle outgrow its shell? Unlike a hermit crab,
Speaker 1: a turtle isn't able to trade in one shell for
Speaker 1: another if it's damaged or just doesn't fit anymore. Hermit
Speaker 1: crabs will trade shells because they don't grow their own.
Speaker 1: They find their shells in their environments. But a turtle's
Speaker 1: shell never falls off and is never too large or
Speaker 1: too small because it grows with the turtle. It's made
Speaker 1: from the turtle's rib cage and spine, and it's attached
Speaker 1: to the internal bones with the turtle's body. Just as
Speaker 1: your vertebrae grow with you, are the same as true
Speaker 1: for a turtle's shell. For most species, as the turtle
Speaker 1: and its shell grow, the scoots on the shell shed
Speaker 1: or peel away to make room for new, larger scoots.
Speaker 1: The shedding is a natural process that takes place over time,
Speaker 1: and individual scoots are cast off during daily activities like
Speaker 1: swimming and basking in the sun. Because turtles are cold
Speaker 1: blooded reptiles, they rely on external ways of heating and
Speaker 1: cooling themselves. While basking is one way that turtles raise
Speaker 1: their body temperature, it also helps them shed scoots by
Speaker 1: drying them up, leaving them ready to fall off. Some turtles,
Speaker 1: like the South American river turtle, lend each other a
Speaker 1: hand in the shedding process. Well, they lend each other
Speaker 1: a jaw by pulling loose scoots and algae off each
Speaker 1: other's shells. This is done gently, though, since both pain
Speaker 1: and pressure can be felt through the shell. When old
Speaker 1: scoots aren't suitably shed, turtle shells can develop infection and disease.
Speaker 1: In rare instances, scoots are shed too frequently, leaving the
Speaker 1: bones of the shell unprotected and soft. Overabundant scoots, shedding
Speaker 1: has been linked to larger problems like renal failure. Shell
Speaker 1: health is also dependent on bone health. A metabolic bone
Speaker 1: disease caused by inadequate calcium intake of poor exposure to sunlight,
Speaker 1: as well as diseases of the liver, kidneys, and thyroid
Speaker 1: can all result in soft or misshapen shell bones. Ulcers,
Speaker 1: also known as shell rot, can cause permanent shell and
Speaker 1: scute deformities. Shell disease doesn't occur as frequently as injury,
Speaker 1: though fractured shells are common and happen when turtles are
Speaker 1: hit by cars or attacked by other wildlife. Some veterinarians
Speaker 1: are able to repair broken shells with bonding materials, but
Speaker 1: one of the fantastic things about a turtle's shell is that,
Speaker 1: since it's made of living materials, it can slowly repair
Speaker 1: itself and regrow Today's episode is based on the article
Speaker 1: can a Turtle Outgrow its Shell? On How Stuff Works?
Speaker 1: Written by Maria Tremarchy. Brain Stuff is production of iHeartRadio
Speaker 1: in partnership with HowStuffWorks dot Com and is produced by
Speaker 1: Tyler Klang. Four more podcasts my heart Radio, visit the
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