Speaker 1: Welcome to Brainstuff, a production of iHeart Radio, Hey brain
Speaker 1: Stuff Lauren vocal bom Here. The rattlesnakes depicted on yellow
Speaker 1: Gadsden flags and Craig Ferguson's coffee mug are all American
Speaker 1: pit vipers noted for their venom. Vipers make up a
Speaker 1: wide spread snake family that's represented on most of the
Speaker 1: world's continents, Australia and Antarctica being the two exceptions. All
Speaker 1: vipers carry venom in twin glands behind their eyes. The
Speaker 1: toxic brew is delivered through movable fangs that can be
Speaker 1: folded up against the roof of the snake's mouth. Rattlesnakes
Speaker 1: bring something extra to the table, though they belong to
Speaker 1: a viper subfamily called Crotolina, or the pit vipers. Such
Speaker 1: reptiles come with an amazing built in tool that they
Speaker 1: used to locate prey and predator alike. We don't call
Speaker 1: them pit vipers because they hang out in ditches or
Speaker 1: attend the University of Pittsburgh. Instead, that name to drives
Speaker 1: from the heat sensitive holes, that is, pits located between
Speaker 1: their eyeballs and nasal openings. But we spoke via email
Speaker 1: with herpetologist Emily Taylor. She explained pit vipers are distinguished
Speaker 1: by the two infrared sensing pits on their faces. Other
Speaker 1: vipers lack these pits and also lack the ability to
Speaker 1: sense infrared radiation. Other sneaks like boa and pythons, also
Speaker 1: do have pit organs, though the structures are different. I'm
Speaker 1: discovered in the year eighteen hundred. Infrared radiation, also called
Speaker 1: i R or infrared light, is a type of radiant
Speaker 1: energy on the electromagnetic spectrum that's invisible to the human eye,
Speaker 1: but you're giving off infrared radiation right now. Every object
Speaker 1: in the universe with a temperature above absolute zero that
Speaker 1: is negative four hundred and fifty nine point eight degrees
Speaker 1: fahrenheit or negative two hundred and seventy three point one
Speaker 1: five degrees celsius emits some amount of infrared radiation. Shin
Speaker 1: things that are physically warmer give off more infrared radiation.
Speaker 1: We can sense that energy as heat like night vision goggles.
Speaker 1: Pit vipers facial pits are also used to detect infrared radiation.
Speaker 1: But we also spoke via email with wildlife biologist Andrew Derso,
Speaker 1: who explained that these structures are quote essentially very simple
Speaker 1: eyes that see in the infrared spectrum. They have a
Speaker 1: narrow opening leading to a wider cavity in the middle
Speaker 1: of which a membrane filled with infrared receptors is suspended
Speaker 1: away from the body, acting as a retina. This lets
Speaker 1: snakes see thermal images of nearby animals. Since many pit
Speaker 1: vipers go hunting after dark for rodents, birds, and utter
Speaker 1: creatures that are warmer than themselves. It's a helpful superpower,
Speaker 1: and Taylor said their real eyes do not sense this radiation. However,
Speaker 1: the sensory information from their eyes of photo reception and
Speaker 1: their pits thermo reception is likely merged in their brain
Speaker 1: in some way. It's impossible to know for sure what
Speaker 1: it looks like to the snake, but it's likely that
Speaker 1: they combine the input from their eyes and from their
Speaker 1: pits into some sort of dual image. When dinner's insight,
Speaker 1: vipers lash out with sophisticated fangs, hinged and capable of
Speaker 1: moving independently. These are long, tubular teeth, and they're hollow too.
Speaker 1: Venom is released through a slit near the tip. Taylor
Speaker 1: said snake venoms are cocktails of thousands of chemicals, mostly
Speaker 1: proteins that disrupt physiological pathways in the prey. Biological toxins
Speaker 1: fall into a number of different categories. Two of the
Speaker 1: major groups are known as hemotoxins and neurotoxins, and Taylor
Speaker 1: explained hemotoxins disrupt the coagulation of blood and cause internal bleeding.
Speaker 1: Neurotoxins interfere with the normal nervous system functions at multiple levels,
Speaker 1: for example by blocking neurotransmitter release or reuptake, or by
Speaker 1: preventing neurotransmitters from binding. The result is that muscles cannot contract,
Speaker 1: and envenomated prey often die when their diaphragm, which is
Speaker 1: the main muscle used for breathing, can no longer contract.
Speaker 1: Many venomous snakes, including pit vipers, have multiple hemotoxins and
Speaker 1: neurotoxins in their venoms. Ambush hunting is a pit viper specialty.
Speaker 1: Most of the time, the snakes wait for their prey
Speaker 1: to come to them instead of chasing it down y
Speaker 1: waste energy. When a pit viper lashes out, the reptile
Speaker 1: can strike with up to half of its total body length.
Speaker 1: Some have been clocked moving their heads at eight feet
Speaker 1: or over two meters per second in the process. That's
Speaker 1: not to say that they always hit the target. Experiments
Speaker 1: involving a Chinese pit vipers showed that adults strike more
Speaker 1: accurately than juveniles. Halfway around the world, Kangaroo rats can
Speaker 1: use a vase of maneuvers to dodge mojave rattle snakes
Speaker 1: in mid strike. Ironically, road runners actively goad rattlesnakes into striking.
Speaker 1: The birds eat small rattlers despite having no natural resistance
Speaker 1: to their venom. A road runners first move is to
Speaker 1: pester one of these snakes until the reptile tries to
Speaker 1: strike back. Then, while the snake's body is fully extended,
Speaker 1: the bird will grab the head before our rattler can react,
Speaker 1: its attacker whips the skull against the ground. Red tailed
Speaker 1: hawks employ a similar strategy. Pit Vipers are also killed
Speaker 1: by non venomous king snakes, who swallow rattlers, cotton mouths,
Speaker 1: and copper heads whole. People would do well to keep
Speaker 1: their distance, though, While snake bite fatalities are rare in
Speaker 1: the United States, with only five to six human deaths
Speaker 1: occurring per year, pit viper in venomation may lead to shock, swelling, bruising, blistering, paralysis,
Speaker 1: and other delightful symptoms. Many pit vipers reside in the Americas,
Speaker 1: though the subfamily also extends into parts of Southeast Asia.
Speaker 1: Besides rattlers, the list of pit vipers includes cotton mounts,
Speaker 1: copper heads, and the bushmaster snakes. There are two hundred
Speaker 1: and sixty species currently recognized. Today's episode was written by
Speaker 1: Mark Mancini and produced by Tyler Clang. For more in
Speaker 1: this and lots of other striking topics, visit how stuff
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