Newly Confirmed Jumping Leeches Are the Worst Fear You Didn't Know You Had

White men can’t jump, but terrestrial leeches can. This is present a technological fact; aft centuries of anecdotal reports, the parasites person been caught connected video leaping from leaves successful the Madagascan rainforest.

The footage was archetypal captured successful 2017 by Mai Fahmy, a researcher present astatine the American Museum of Natural History. She had a accidental brushwood with a leech extending its assemblage retired successful hunt of a host, a behaviour known arsenic “questing.” The adventurous leech was encountered successful Madagascar’s Ranomafana National Park.

Fahmy whipped retired her telephone and captured the leech inching guardant and past springing disconnected the leaf, landing with a flail oregon 2 connected the wood floor. The footage—as good arsenic a 2023 video showcasing the acrobatics—was published contiguous successful Biotropica.

“Even though I was retired successful the tract successful Madagascar collecting leeches for bloodmeal analysis, the unit was connected to effort to spot if we could get different video to enactment the assertion that we marque successful the paper,” Fahmy said. With the work of the research, the squad vindicates anecdotal grounds that the terrestrial parasites (at slightest the taxon Chtonobdella fallax) leap successful hunt of a warm, blood-filled morsel connected which to feed.

Jumping leeches adjacent got into the chronicles of celebrated 14th-century explorer Ibn Battuta, who documented the behaviour successful leeches successful Sri Lanka, indicating that the behaviour whitethorn person independently evolved successful assorted terrestrial leeches. But by the mid-20th century, the conception of jumping leeches was viewed much skeptically successful technological publications.

“A batch of the past of this fundamentally comes down to that question: ‘What precisely is simply a jump?’ For hundreds of years, determination were anecdotes from truly highly well-trained observers astir jumping leeches,” said Michael Tessler, an invertebrate zoologist astatine the American Museum of Natural History and Medger Evers College, successful a telephone telephone with Gizmodo. “It wasn’t until radical started much earnestly studying leeches, benignant of successful the 1800s, aboriginal 1900s, that astir each leech biologist who spent clip with these things said, ‘no mode they can’t jump.’”

It was nary concealed that leeches sometimes autumn onto their hosts, but the question connected the array was astir intentionality: Do the leeches expend vigor launching towards a fixed people (or simply into the air), oregon are they toppling, allowing gravity to enactment for them? Now, the video grounds documents the parasites doing the former, coiling up and past springing guardant into the unknown. The animals surely determination outwards from their leafy launchpad, and—the squad argues—perhaps somewhat upward. In different words, they jump.

Fahmy with a leech connected her face. Leeches often onshore connected their hosts from supra successful Madagascar.Photo: Mariah Donohue

Tessler said the leeches are apt jumping successful their hunt for a host. After they quest to question retired question oregon vigor from a imaginable meal, the animals whitethorn leap arsenic a benignant of leap of religion towards the host.

Fahmy has been bitten by leeches before, including astatine slightest 1 lawsuit of 1 of the parasites landing successful her eye. The leeches similar to spell for the eyes, she said. When captured, the animals’ bloodmeals tin beryllium sampled to get an knowing of the animals successful the rainforest. The leech is fundamentally a mobile environmental DNA lab.

“I’ll beryllium going backmost to Madagascar for years to come,” Fahmy said. “I’ll person my eyes connected the leeches. We cognize truthful small astir their biology, their earthy history, their behaviors. They’re afloat of mystery.”

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