1 00:00:01,920 --> 00:00:06,720 Speaker 1: Welcome to Brainstuff, a production of iHeart Radio, Hey brain 2 00:00:06,720 --> 00:00:11,040 Speaker 1: Stuff Lauren vocal bom Here. The rattlesnakes depicted on yellow 3 00:00:11,039 --> 00:00:15,080 Speaker 1: Gadsden flags and Craig Ferguson's coffee mug are all American 4 00:00:15,160 --> 00:00:18,439 Speaker 1: pit vipers noted for their venom. Vipers make up a 5 00:00:18,480 --> 00:00:21,480 Speaker 1: wide spread snake family that's represented on most of the 6 00:00:21,520 --> 00:00:26,520 Speaker 1: world's continents, Australia and Antarctica being the two exceptions. All 7 00:00:26,760 --> 00:00:30,920 Speaker 1: vipers carry venom in twin glands behind their eyes. The 8 00:00:31,000 --> 00:00:34,120 Speaker 1: toxic brew is delivered through movable fangs that can be 9 00:00:34,159 --> 00:00:38,240 Speaker 1: folded up against the roof of the snake's mouth. Rattlesnakes 10 00:00:38,320 --> 00:00:41,479 Speaker 1: bring something extra to the table, though they belong to 11 00:00:41,520 --> 00:00:46,160 Speaker 1: a viper subfamily called Crotolina, or the pit vipers. Such 12 00:00:46,159 --> 00:00:49,199 Speaker 1: reptiles come with an amazing built in tool that they 13 00:00:49,280 --> 00:00:53,519 Speaker 1: used to locate prey and predator alike. We don't call 14 00:00:53,600 --> 00:00:56,240 Speaker 1: them pit vipers because they hang out in ditches or 15 00:00:56,360 --> 00:01:00,360 Speaker 1: attend the University of Pittsburgh. Instead, that name to drives 16 00:01:00,400 --> 00:01:04,400 Speaker 1: from the heat sensitive holes, that is, pits located between 17 00:01:04,440 --> 00:01:08,800 Speaker 1: their eyeballs and nasal openings. But we spoke via email 18 00:01:08,800 --> 00:01:13,520 Speaker 1: with herpetologist Emily Taylor. She explained pit vipers are distinguished 19 00:01:13,560 --> 00:01:17,240 Speaker 1: by the two infrared sensing pits on their faces. Other 20 00:01:17,360 --> 00:01:20,560 Speaker 1: vipers lack these pits and also lack the ability to 21 00:01:20,640 --> 00:01:25,880 Speaker 1: sense infrared radiation. Other sneaks like boa and pythons, also 22 00:01:26,000 --> 00:01:29,959 Speaker 1: do have pit organs, though the structures are different. I'm 23 00:01:29,959 --> 00:01:33,959 Speaker 1: discovered in the year eighteen hundred. Infrared radiation, also called 24 00:01:34,040 --> 00:01:37,160 Speaker 1: i R or infrared light, is a type of radiant 25 00:01:37,240 --> 00:01:41,000 Speaker 1: energy on the electromagnetic spectrum that's invisible to the human eye, 26 00:01:41,760 --> 00:01:46,120 Speaker 1: but you're giving off infrared radiation right now. Every object 27 00:01:46,160 --> 00:01:49,200 Speaker 1: in the universe with a temperature above absolute zero that 28 00:01:49,360 --> 00:01:52,400 Speaker 1: is negative four hundred and fifty nine point eight degrees 29 00:01:52,440 --> 00:01:55,680 Speaker 1: fahrenheit or negative two hundred and seventy three point one 30 00:01:55,800 --> 00:02:00,200 Speaker 1: five degrees celsius emits some amount of infrared radiation. Shin 31 00:02:00,600 --> 00:02:04,080 Speaker 1: things that are physically warmer give off more infrared radiation. 32 00:02:04,560 --> 00:02:09,560 Speaker 1: We can sense that energy as heat like night vision goggles. 33 00:02:09,680 --> 00:02:13,720 Speaker 1: Pit vipers facial pits are also used to detect infrared radiation. 34 00:02:14,880 --> 00:02:19,160 Speaker 1: But we also spoke via email with wildlife biologist Andrew Derso, 35 00:02:19,280 --> 00:02:23,680 Speaker 1: who explained that these structures are quote essentially very simple 36 00:02:23,760 --> 00:02:27,560 Speaker 1: eyes that see in the infrared spectrum. They have a 37 00:02:27,639 --> 00:02:30,720 Speaker 1: narrow opening leading to a wider cavity in the middle 38 00:02:30,760 --> 00:02:34,440 Speaker 1: of which a membrane filled with infrared receptors is suspended 39 00:02:34,480 --> 00:02:39,400 Speaker 1: away from the body, acting as a retina. This lets 40 00:02:39,520 --> 00:02:44,120 Speaker 1: snakes see thermal images of nearby animals. Since many pit 41 00:02:44,280 --> 00:02:47,600 Speaker 1: vipers go hunting after dark for rodents, birds, and utter 42 00:02:47,600 --> 00:02:51,200 Speaker 1: creatures that are warmer than themselves. It's a helpful superpower, 43 00:02:51,760 --> 00:02:56,600 Speaker 1: and Taylor said their real eyes do not sense this radiation. However, 44 00:02:56,760 --> 00:03:00,080 Speaker 1: the sensory information from their eyes of photo reception and 45 00:03:00,160 --> 00:03:03,680 Speaker 1: their pits thermo reception is likely merged in their brain 46 00:03:03,760 --> 00:03:06,720 Speaker 1: in some way. It's impossible to know for sure what 47 00:03:06,800 --> 00:03:09,360 Speaker 1: it looks like to the snake, but it's likely that 48 00:03:09,400 --> 00:03:12,000 Speaker 1: they combine the input from their eyes and from their 49 00:03:12,000 --> 00:03:16,840 Speaker 1: pits into some sort of dual image. When dinner's insight, 50 00:03:17,200 --> 00:03:21,640 Speaker 1: vipers lash out with sophisticated fangs, hinged and capable of 51 00:03:21,639 --> 00:03:26,880 Speaker 1: moving independently. These are long, tubular teeth, and they're hollow too. 52 00:03:27,560 --> 00:03:31,280 Speaker 1: Venom is released through a slit near the tip. Taylor 53 00:03:31,360 --> 00:03:35,240 Speaker 1: said snake venoms are cocktails of thousands of chemicals, mostly 54 00:03:35,320 --> 00:03:41,400 Speaker 1: proteins that disrupt physiological pathways in the prey. Biological toxins 55 00:03:41,400 --> 00:03:43,960 Speaker 1: fall into a number of different categories. Two of the 56 00:03:44,000 --> 00:03:48,600 Speaker 1: major groups are known as hemotoxins and neurotoxins, and Taylor 57 00:03:48,640 --> 00:03:54,000 Speaker 1: explained hemotoxins disrupt the coagulation of blood and cause internal bleeding. 58 00:03:54,480 --> 00:03:58,680 Speaker 1: Neurotoxins interfere with the normal nervous system functions at multiple levels, 59 00:03:59,040 --> 00:04:02,880 Speaker 1: for example by blocking neurotransmitter release or reuptake, or by 60 00:04:02,920 --> 00:04:08,120 Speaker 1: preventing neurotransmitters from binding. The result is that muscles cannot contract, 61 00:04:08,560 --> 00:04:12,320 Speaker 1: and envenomated prey often die when their diaphragm, which is 62 00:04:12,320 --> 00:04:15,320 Speaker 1: the main muscle used for breathing, can no longer contract. 63 00:04:15,960 --> 00:04:20,240 Speaker 1: Many venomous snakes, including pit vipers, have multiple hemotoxins and 64 00:04:20,440 --> 00:04:26,920 Speaker 1: neurotoxins in their venoms. Ambush hunting is a pit viper specialty. 65 00:04:27,279 --> 00:04:29,440 Speaker 1: Most of the time, the snakes wait for their prey 66 00:04:29,480 --> 00:04:32,240 Speaker 1: to come to them instead of chasing it down y 67 00:04:32,320 --> 00:04:36,080 Speaker 1: waste energy. When a pit viper lashes out, the reptile 68 00:04:36,160 --> 00:04:38,839 Speaker 1: can strike with up to half of its total body length. 69 00:04:39,400 --> 00:04:41,880 Speaker 1: Some have been clocked moving their heads at eight feet 70 00:04:42,000 --> 00:04:45,760 Speaker 1: or over two meters per second in the process. That's 71 00:04:45,800 --> 00:04:48,440 Speaker 1: not to say that they always hit the target. Experiments 72 00:04:48,480 --> 00:04:51,640 Speaker 1: involving a Chinese pit vipers showed that adults strike more 73 00:04:51,680 --> 00:04:56,080 Speaker 1: accurately than juveniles. Halfway around the world, Kangaroo rats can 74 00:04:56,200 --> 00:04:58,960 Speaker 1: use a vase of maneuvers to dodge mojave rattle snakes 75 00:04:59,000 --> 00:05:05,520 Speaker 1: in mid strike. Ironically, road runners actively goad rattlesnakes into striking. 76 00:05:06,080 --> 00:05:09,840 Speaker 1: The birds eat small rattlers despite having no natural resistance 77 00:05:09,839 --> 00:05:12,440 Speaker 1: to their venom. A road runners first move is to 78 00:05:12,440 --> 00:05:14,839 Speaker 1: pester one of these snakes until the reptile tries to 79 00:05:14,880 --> 00:05:18,440 Speaker 1: strike back. Then, while the snake's body is fully extended, 80 00:05:18,720 --> 00:05:22,200 Speaker 1: the bird will grab the head before our rattler can react, 81 00:05:22,440 --> 00:05:26,159 Speaker 1: its attacker whips the skull against the ground. Red tailed 82 00:05:26,200 --> 00:05:30,560 Speaker 1: hawks employ a similar strategy. Pit Vipers are also killed 83 00:05:30,600 --> 00:05:34,600 Speaker 1: by non venomous king snakes, who swallow rattlers, cotton mouths, 84 00:05:34,600 --> 00:05:38,599 Speaker 1: and copper heads whole. People would do well to keep 85 00:05:38,600 --> 00:05:42,000 Speaker 1: their distance, though, While snake bite fatalities are rare in 86 00:05:42,040 --> 00:05:44,760 Speaker 1: the United States, with only five to six human deaths 87 00:05:44,760 --> 00:05:50,960 Speaker 1: occurring per year, pit viper in venomation may lead to shock, swelling, bruising, blistering, paralysis, 88 00:05:51,000 --> 00:05:56,800 Speaker 1: and other delightful symptoms. Many pit vipers reside in the Americas, 89 00:05:56,839 --> 00:05:59,919 Speaker 1: though the subfamily also extends into parts of Southeast Asia. 90 00:06:00,520 --> 00:06:03,880 Speaker 1: Besides rattlers, the list of pit vipers includes cotton mounts, 91 00:06:03,920 --> 00:06:07,279 Speaker 1: copper heads, and the bushmaster snakes. There are two hundred 92 00:06:07,320 --> 00:06:15,960 Speaker 1: and sixty species currently recognized. Today's episode was written by 93 00:06:15,960 --> 00:06:18,640 Speaker 1: Mark Mancini and produced by Tyler Clang. For more in 94 00:06:18,680 --> 00:06:21,000 Speaker 1: this and lots of other striking topics, visit how stuff 95 00:06:21,040 --> 00:06:23,920 Speaker 1: works dot com. Brain Stuff is production of iHeart Radio 96 00:06:24,200 --> 00:06:26,440 Speaker 1: or more podcasts. My heart Radio visit the i heart 97 00:06:26,520 --> 00:06:29,080 Speaker 1: Radio app, Apple Podcasts, or wherever you listen to your 98 00:06:29,120 --> 00:06:29,800 Speaker 1: favorite shows.