Speaker 1: Welcome to Brainstuff, a production of iHeartRadio. Hey Brainstuff, Lauren
Speaker 1: Vogelbaum here. Every now and again, Americans get word that
Speaker 1: a new killer creature is invading our country. Killer bees,
Speaker 1: murder hornets, fire ants, and on and on. It keeps
Speaker 1: the news. Spicy hammerhead flat worms commonly called hammerhead worms,
Speaker 1: occasionally make their way into the rotation because they're not
Speaker 1: native to many places in the world, and they're toxic
Speaker 1: and aggressive predators, and they're slimy and leech like with
Speaker 1: anvil shaped heads. But unlike many other terrestrial worms, they
Speaker 1: can grow to around eighteen inches or forty five centimeters long.
Speaker 1: People sometimes mistake them for snakes, but hammerhead worms aren't
Speaker 1: anything to get too fussed about. They're not a new
Speaker 1: thing in the US nor in most other places in
Speaker 1: the world. They've been common residents of American gardens the
Speaker 1: early nineteen hundreds. These predatory planarians are native to tropical
Speaker 1: and subtropical regions of the globe. Over the course of
Speaker 1: the past couple hundred years, a global commerce has helped
Speaker 1: the hammerhead worm wriggle its way into most suitable habitats
Speaker 1: in the world, and there are a lot of suitably warm,
Speaker 1: wet habitats out there, though you're unlikely to find them
Speaker 1: in a desert or at the top of a mountain.
Speaker 1: For the article, this episode is based on how Stuff Works.
Speaker 1: Spoke with Matt Bertone, an entomologist at NC State University.
Speaker 1: He said, as some have been here for over a
Speaker 1: hundred years, so they're well established. They easily hide among
Speaker 1: objects and in soil where there's moisture, so moving any
Speaker 1: type of container or plants around the world has allowed
Speaker 1: them to colonize new areas. Thus, they are highly invasive
Speaker 1: and frequently show up in new regions. Hammerhead worms are
Speaker 1: carnivorous and often cannibalistic. They're sensitive to light and our
Speaker 1: active mostly at night, feeding on a variety of small,
Speaker 1: soft bodied animals snails, slugs, and earthworms mostly, though they
Speaker 1: occasionally feed on other small invertebrates like insects. Bertone explained
Speaker 1: they wrap around their prey with sticky mucus and use
Speaker 1: a mouth located on their belly in the middle of
Speaker 1: the body to consume prey. They use special enzymes to
Speaker 1: digest the prey outside of their body after the digestive
Speaker 1: juices have done their business effectively turning prey into a
Speaker 1: puddle of goo. The hammerhead worm sucks its victim in
Speaker 1: with the help of a bunch of tiny hair like
Speaker 1: structures on its underside, called cilia. The cilia also helped
Speaker 1: the worms in locomotion, acting like hundreds of microscopic legs
Speaker 1: to pull them along on a thin film of slime
Speaker 1: that the worms excrete. The life cycles of flatworms are
Speaker 1: complex and differ from species to species. Hammerhead worms are hermaphroditic.
Speaker 1: They have both male and female productive organs, and can
Speaker 1: reproduce either sexually or asexually, though asexual reproduction is more common.
Speaker 1: For instance, a species native to Southeast Asia but common
Speaker 1: worldwide typically reproduce by fission, especially when they're outside their
Speaker 1: native range. In this process, a small portion of the
Speaker 1: body near the tail pinches off and becomes a new worm,
Speaker 1: a clone of its parent. Another species, Eggs are produced
Speaker 1: when they mate with other worms, self fertilize or clone themselves.
Speaker 1: But why are they considered so hazardous? Bertone explained. Species
Speaker 1: of hammerhead flatworms are the only known terrestrial invertebrates that
Speaker 1: produce to trototoxin, the poison that makes pufferfish deadly. However,
Speaker 1: they do so only in small amounts and are not
Speaker 1: dangerous to humans in less eaten in large numbers. Thus
Speaker 1: their danger is often overexaggerated. Hammerhead worms do pose a
Speaker 1: real threat to earthwork populations, however. For instance, researchers are
Speaker 1: concerned about the populations in France, where the presence of
Speaker 1: hammerhead worms had somehow gone undetected by scientists and gardeners
Speaker 1: alike for more than twenty years. The concern is that
Speaker 1: hammerhead worms, which don't aerrate and fertilize the soil the
Speaker 1: way that earthworms do, have been eating earthworms and other
Speaker 1: helpful soil fauna in scarcity. Today's episode is based on
Speaker 1: the article hammerhead worms are toxic and invasive, But are
Speaker 1: they dangerous? On holstaffworks dot com written by Jesslyin Shields.
Speaker 1: Brainstuff is production of by Heart Radio in partnership withhustaffworks
Speaker 1: dot com, and it is produced by Tyler Klang. Four
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