1 00:00:01,840 --> 00:00:07,480 Speaker 1: Welcome to Brainstuff, a production of iHeartRadio, Hey brain Stuff 2 00:00:07,520 --> 00:00:13,160 Speaker 1: Lauren vogelbamb Here. Turtle is the common American English word 3 00:00:13,280 --> 00:00:16,600 Speaker 1: for the three hundred and fifty sum species of reptiles 4 00:00:16,760 --> 00:00:21,480 Speaker 1: known for their characteristic shells. Sometimes you might see, especially 5 00:00:21,480 --> 00:00:26,680 Speaker 1: in British English, distinctions between land based tortoises, freshwater terrapins, 6 00:00:26,720 --> 00:00:30,880 Speaker 1: and marine turtles. But today I'm talking about the whole 7 00:00:30,920 --> 00:00:35,440 Speaker 1: mess of them using the word turtle. Okay, okay. They 8 00:00:35,560 --> 00:00:39,760 Speaker 1: live in oceans, lakes, streams, forests, and deserts all over 9 00:00:39,800 --> 00:00:42,920 Speaker 1: the world except Antarctica. They might be in a yard 10 00:00:43,000 --> 00:00:48,360 Speaker 1: or pond near you, and those shells are amazing adaptations. 11 00:00:48,960 --> 00:00:51,560 Speaker 1: The shape of a turtle shell depends on the species 12 00:00:51,600 --> 00:00:55,280 Speaker 1: and the turtle's habitat. Most land dwelling turtles have a high, 13 00:00:55,280 --> 00:00:58,680 Speaker 1: domed shell, which helps protect them from the jaws of predators, 14 00:00:59,080 --> 00:01:02,320 Speaker 1: while most aquatic turtles have a more streamlined, flattened shell 15 00:01:02,560 --> 00:01:06,880 Speaker 1: that lets them glide through the water. Turtle's shells are 16 00:01:06,920 --> 00:01:09,880 Speaker 1: made up of two parts, the carapas, which is the 17 00:01:10,000 --> 00:01:13,400 Speaker 1: upper half on the turtle's back, and the plastrin, which 18 00:01:13,440 --> 00:01:17,759 Speaker 1: is the lower half under the turtle's belly. Structures called bridges, 19 00:01:17,800 --> 00:01:21,080 Speaker 1: fasten the two together. The turtle sides. They're generally bony, 20 00:01:21,120 --> 00:01:24,800 Speaker 1: but in soft shell turtles they're flexible. For the many 21 00:01:24,800 --> 00:01:28,000 Speaker 1: species of turtles able to retract into their shells, a 22 00:01:28,200 --> 00:01:31,400 Speaker 1: hinge joins the two halves together That allows the carapas 23 00:01:31,400 --> 00:01:34,720 Speaker 1: and plastron to close tightly when the turtle draws itself in. 24 00:01:36,959 --> 00:01:40,600 Speaker 1: Both the carapus and plastron are made of bone, including 25 00:01:40,640 --> 00:01:43,240 Speaker 1: about fifty to sixty rib and backbones in the upper 26 00:01:43,240 --> 00:01:46,319 Speaker 1: shell and a fusion of clavical and rib bones in 27 00:01:46,360 --> 00:01:51,640 Speaker 1: the lower shell. On the outside of the bone, each 28 00:01:51,680 --> 00:01:55,800 Speaker 1: shell half is covered in scoots, sometimes called shields, which 29 00:01:55,840 --> 00:01:59,960 Speaker 1: are overlapping pieces of keratin the same substance as human fingernail. 30 00:02:00,840 --> 00:02:05,000 Speaker 1: The scoots provide a protective coating. Most soft shelled species 31 00:02:05,040 --> 00:02:08,000 Speaker 1: don't have scoots, but they do have a layer of tough, 32 00:02:08,120 --> 00:02:14,680 Speaker 1: leathery skin. So a turtle's shell offers intricate skeletal protection. 33 00:02:15,360 --> 00:02:21,160 Speaker 1: But can a turtle outgrow its shell? Unlike a hermit crab, 34 00:02:21,320 --> 00:02:23,800 Speaker 1: a turtle isn't able to trade in one shell for 35 00:02:23,840 --> 00:02:28,000 Speaker 1: another if it's damaged or just doesn't fit anymore. Hermit 36 00:02:28,040 --> 00:02:30,520 Speaker 1: crabs will trade shells because they don't grow their own. 37 00:02:30,960 --> 00:02:34,200 Speaker 1: They find their shells in their environments. But a turtle's 38 00:02:34,200 --> 00:02:36,920 Speaker 1: shell never falls off and is never too large or 39 00:02:36,960 --> 00:02:41,040 Speaker 1: too small because it grows with the turtle. It's made 40 00:02:41,040 --> 00:02:43,640 Speaker 1: from the turtle's rib cage and spine, and it's attached 41 00:02:43,680 --> 00:02:46,639 Speaker 1: to the internal bones with the turtle's body. Just as 42 00:02:46,680 --> 00:02:49,240 Speaker 1: your vertebrae grow with you, are the same as true 43 00:02:49,280 --> 00:02:54,440 Speaker 1: for a turtle's shell. For most species, as the turtle 44 00:02:54,480 --> 00:02:57,760 Speaker 1: and its shell grow, the scoots on the shell shed 45 00:02:57,919 --> 00:03:01,160 Speaker 1: or peel away to make room for new, larger scoots. 46 00:03:01,720 --> 00:03:05,120 Speaker 1: The shedding is a natural process that takes place over time, 47 00:03:05,360 --> 00:03:08,880 Speaker 1: and individual scoots are cast off during daily activities like 48 00:03:08,960 --> 00:03:14,040 Speaker 1: swimming and basking in the sun. Because turtles are cold 49 00:03:14,080 --> 00:03:17,680 Speaker 1: blooded reptiles, they rely on external ways of heating and 50 00:03:17,720 --> 00:03:21,600 Speaker 1: cooling themselves. While basking is one way that turtles raise 51 00:03:21,639 --> 00:03:24,840 Speaker 1: their body temperature, it also helps them shed scoots by 52 00:03:24,960 --> 00:03:29,200 Speaker 1: drying them up, leaving them ready to fall off. Some turtles, 53 00:03:29,400 --> 00:03:31,960 Speaker 1: like the South American river turtle, lend each other a 54 00:03:32,040 --> 00:03:35,160 Speaker 1: hand in the shedding process. Well, they lend each other 55 00:03:35,280 --> 00:03:38,240 Speaker 1: a jaw by pulling loose scoots and algae off each 56 00:03:38,280 --> 00:03:42,400 Speaker 1: other's shells. This is done gently, though, since both pain 57 00:03:42,520 --> 00:03:47,280 Speaker 1: and pressure can be felt through the shell. When old 58 00:03:47,280 --> 00:03:51,360 Speaker 1: scoots aren't suitably shed, turtle shells can develop infection and disease. 59 00:03:52,280 --> 00:03:56,080 Speaker 1: In rare instances, scoots are shed too frequently, leaving the 60 00:03:56,080 --> 00:04:00,160 Speaker 1: bones of the shell unprotected and soft. Overabundant scoots, shedding 61 00:04:00,240 --> 00:04:05,480 Speaker 1: has been linked to larger problems like renal failure. Shell 62 00:04:05,560 --> 00:04:09,000 Speaker 1: health is also dependent on bone health. A metabolic bone 63 00:04:09,000 --> 00:04:12,760 Speaker 1: disease caused by inadequate calcium intake of poor exposure to sunlight, 64 00:04:13,000 --> 00:04:16,080 Speaker 1: as well as diseases of the liver, kidneys, and thyroid 65 00:04:16,320 --> 00:04:20,719 Speaker 1: can all result in soft or misshapen shell bones. Ulcers, 66 00:04:20,839 --> 00:04:23,599 Speaker 1: also known as shell rot, can cause permanent shell and 67 00:04:23,640 --> 00:04:30,120 Speaker 1: scute deformities. Shell disease doesn't occur as frequently as injury, 68 00:04:30,279 --> 00:04:34,360 Speaker 1: though fractured shells are common and happen when turtles are 69 00:04:34,440 --> 00:04:39,080 Speaker 1: hit by cars or attacked by other wildlife. Some veterinarians 70 00:04:39,120 --> 00:04:42,479 Speaker 1: are able to repair broken shells with bonding materials, but 71 00:04:42,760 --> 00:04:45,760 Speaker 1: one of the fantastic things about a turtle's shell is that, 72 00:04:45,839 --> 00:04:49,480 Speaker 1: since it's made of living materials, it can slowly repair 73 00:04:49,520 --> 00:04:57,599 Speaker 1: itself and regrow Today's episode is based on the article 74 00:04:57,760 --> 00:05:00,000 Speaker 1: can a Turtle Outgrow its Shell? On How Stuff Works? 75 00:05:00,600 --> 00:05:04,240 Speaker 1: Written by Maria Tremarchy. Brain Stuff is production of iHeartRadio 76 00:05:04,320 --> 00:05:06,840 Speaker 1: in partnership with HowStuffWorks dot Com and is produced by 77 00:05:06,839 --> 00:05:10,360 Speaker 1: Tyler Klang. Four more podcasts my heart Radio, visit the 78 00:05:10,400 --> 00:05:13,600 Speaker 1: iHeartRadio app, Apple Podcasts, or wherever you listen to your 79 00:05:13,600 --> 00:05:14,400 Speaker 1: favorite shows.