1 00:00:01,800 --> 00:00:07,720 Speaker 1: Welcome to Brainstuff, a production of iHeartRadio. Hey Brainstuff, Lauren 2 00:00:07,760 --> 00:00:12,319 Speaker 1: Vogelbaum here. Every now and again, Americans get word that 3 00:00:12,440 --> 00:00:16,280 Speaker 1: a new killer creature is invading our country. Killer bees, 4 00:00:16,440 --> 00:00:20,240 Speaker 1: murder hornets, fire ants, and on and on. It keeps 5 00:00:20,239 --> 00:00:25,720 Speaker 1: the news. Spicy hammerhead flat worms commonly called hammerhead worms, 6 00:00:26,040 --> 00:00:29,280 Speaker 1: occasionally make their way into the rotation because they're not 7 00:00:29,400 --> 00:00:32,240 Speaker 1: native to many places in the world, and they're toxic 8 00:00:32,320 --> 00:00:35,879 Speaker 1: and aggressive predators, and they're slimy and leech like with 9 00:00:36,080 --> 00:00:41,040 Speaker 1: anvil shaped heads. But unlike many other terrestrial worms, they 10 00:00:41,040 --> 00:00:44,760 Speaker 1: can grow to around eighteen inches or forty five centimeters long. 11 00:00:45,479 --> 00:00:50,960 Speaker 1: People sometimes mistake them for snakes, but hammerhead worms aren't 12 00:00:50,960 --> 00:00:54,160 Speaker 1: anything to get too fussed about. They're not a new 13 00:00:54,200 --> 00:00:56,600 Speaker 1: thing in the US nor in most other places in 14 00:00:56,600 --> 00:01:00,240 Speaker 1: the world. They've been common residents of American gardens the 15 00:01:00,240 --> 00:01:05,560 Speaker 1: early nineteen hundreds. These predatory planarians are native to tropical 16 00:01:05,600 --> 00:01:08,800 Speaker 1: and subtropical regions of the globe. Over the course of 17 00:01:08,800 --> 00:01:11,759 Speaker 1: the past couple hundred years, a global commerce has helped 18 00:01:11,800 --> 00:01:15,280 Speaker 1: the hammerhead worm wriggle its way into most suitable habitats 19 00:01:15,280 --> 00:01:18,600 Speaker 1: in the world, and there are a lot of suitably warm, 20 00:01:18,640 --> 00:01:21,800 Speaker 1: wet habitats out there, though you're unlikely to find them 21 00:01:21,800 --> 00:01:23,959 Speaker 1: in a desert or at the top of a mountain. 22 00:01:26,160 --> 00:01:28,840 Speaker 1: For the article, this episode is based on how Stuff Works. 23 00:01:28,840 --> 00:01:32,360 Speaker 1: Spoke with Matt Bertone, an entomologist at NC State University. 24 00:01:33,200 --> 00:01:35,600 Speaker 1: He said, as some have been here for over a 25 00:01:35,680 --> 00:01:39,440 Speaker 1: hundred years, so they're well established. They easily hide among 26 00:01:39,520 --> 00:01:43,080 Speaker 1: objects and in soil where there's moisture, so moving any 27 00:01:43,080 --> 00:01:45,959 Speaker 1: type of container or plants around the world has allowed 28 00:01:46,000 --> 00:01:50,040 Speaker 1: them to colonize new areas. Thus, they are highly invasive 29 00:01:50,240 --> 00:01:55,320 Speaker 1: and frequently show up in new regions. Hammerhead worms are 30 00:01:55,360 --> 00:01:59,560 Speaker 1: carnivorous and often cannibalistic. They're sensitive to light and our 31 00:01:59,600 --> 00:02:02,880 Speaker 1: active mostly at night, feeding on a variety of small, 32 00:02:03,000 --> 00:02:07,320 Speaker 1: soft bodied animals snails, slugs, and earthworms mostly, though they 33 00:02:07,320 --> 00:02:12,639 Speaker 1: occasionally feed on other small invertebrates like insects. Bertone explained 34 00:02:13,040 --> 00:02:16,200 Speaker 1: they wrap around their prey with sticky mucus and use 35 00:02:16,240 --> 00:02:18,280 Speaker 1: a mouth located on their belly in the middle of 36 00:02:18,320 --> 00:02:22,160 Speaker 1: the body to consume prey. They use special enzymes to 37 00:02:22,160 --> 00:02:26,919 Speaker 1: digest the prey outside of their body after the digestive 38 00:02:27,000 --> 00:02:30,280 Speaker 1: juices have done their business effectively turning prey into a 39 00:02:30,360 --> 00:02:33,640 Speaker 1: puddle of goo. The hammerhead worm sucks its victim in 40 00:02:33,880 --> 00:02:35,959 Speaker 1: with the help of a bunch of tiny hair like 41 00:02:36,120 --> 00:02:40,640 Speaker 1: structures on its underside, called cilia. The cilia also helped 42 00:02:40,639 --> 00:02:44,840 Speaker 1: the worms in locomotion, acting like hundreds of microscopic legs 43 00:02:44,880 --> 00:02:47,720 Speaker 1: to pull them along on a thin film of slime 44 00:02:47,760 --> 00:02:52,520 Speaker 1: that the worms excrete. The life cycles of flatworms are 45 00:02:52,600 --> 00:02:57,920 Speaker 1: complex and differ from species to species. Hammerhead worms are hermaphroditic. 46 00:02:58,280 --> 00:03:01,440 Speaker 1: They have both male and female productive organs, and can 47 00:03:01,520 --> 00:03:06,760 Speaker 1: reproduce either sexually or asexually, though asexual reproduction is more common. 48 00:03:07,840 --> 00:03:11,160 Speaker 1: For instance, a species native to Southeast Asia but common 49 00:03:11,200 --> 00:03:15,720 Speaker 1: worldwide typically reproduce by fission, especially when they're outside their 50 00:03:15,800 --> 00:03:19,200 Speaker 1: native range. In this process, a small portion of the 51 00:03:19,200 --> 00:03:22,359 Speaker 1: body near the tail pinches off and becomes a new worm, 52 00:03:22,600 --> 00:03:26,240 Speaker 1: a clone of its parent. Another species, Eggs are produced 53 00:03:26,280 --> 00:03:29,880 Speaker 1: when they mate with other worms, self fertilize or clone themselves. 54 00:03:31,400 --> 00:03:37,040 Speaker 1: But why are they considered so hazardous? Bertone explained. Species 55 00:03:37,040 --> 00:03:40,440 Speaker 1: of hammerhead flatworms are the only known terrestrial invertebrates that 56 00:03:40,560 --> 00:03:45,560 Speaker 1: produce to trototoxin, the poison that makes pufferfish deadly. However, 57 00:03:45,840 --> 00:03:48,440 Speaker 1: they do so only in small amounts and are not 58 00:03:48,560 --> 00:03:52,280 Speaker 1: dangerous to humans in less eaten in large numbers. Thus 59 00:03:52,320 --> 00:03:58,520 Speaker 1: their danger is often overexaggerated. Hammerhead worms do pose a 60 00:03:58,520 --> 00:04:03,520 Speaker 1: real threat to earthwork populations, however. For instance, researchers are 61 00:04:03,560 --> 00:04:06,800 Speaker 1: concerned about the populations in France, where the presence of 62 00:04:06,800 --> 00:04:10,840 Speaker 1: hammerhead worms had somehow gone undetected by scientists and gardeners 63 00:04:10,880 --> 00:04:14,280 Speaker 1: alike for more than twenty years. The concern is that 64 00:04:14,360 --> 00:04:17,880 Speaker 1: hammerhead worms, which don't aerrate and fertilize the soil the 65 00:04:17,880 --> 00:04:21,200 Speaker 1: way that earthworms do, have been eating earthworms and other 66 00:04:21,279 --> 00:04:29,280 Speaker 1: helpful soil fauna in scarcity. Today's episode is based on 67 00:04:29,320 --> 00:04:32,680 Speaker 1: the article hammerhead worms are toxic and invasive, But are 68 00:04:32,720 --> 00:04:36,000 Speaker 1: they dangerous? On holstaffworks dot com written by Jesslyin Shields. 69 00:04:36,480 --> 00:04:39,480 Speaker 1: Brainstuff is production of by Heart Radio in partnership withhustaffworks 70 00:04:39,480 --> 00:04:42,000 Speaker 1: dot com, and it is produced by Tyler Klang. Four 71 00:04:42,080 --> 00:04:45,960 Speaker 1: more podcasts my heart Radio, visit the iHeartRadio app, Apple Podcasts, 72 00:04:46,040 --> 00:04:49,120 Speaker 1: or wherever you listen to your favorite shows.