Nature
PUBLISHED
If your nightmares have been feeling a little bland and repetitive recently, don’t worry, we bring you something that’ll be sure to add a fresh smattering of terror – jumping leeches.
The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.The existence of leaping leeches has been a matter of debate since Victorian-era naturalists were kicking about, with some providing field notes of encounters with their acrobatics, whilst others said the parasitic worms had likely dropped down on them from above.
That over 100-year-old debate has now been settled by footage that researchers Mai Fahmy and Michael Tessler believe is the first conclusive evidence that at least one land-dwelling leech species can jump.
In both June 2017 and October 2023, during fieldwork in Madagascar’s Ranomafana National Park and the Ivohiboro Protected Area, Fahmy caught video footage of leeches from the Chtonobdella genus – which is widespread across the island, as well as the Seychelles, Malay Archipelago, and South Pacific Islands – “intentionally jumping off a leaf and onto the ground”.
The leeches do so in a way that the researchers compare to a spring, pulling themselves back in a way that likely maximizes potential energy before launching themselves toward the ground, keeping their bodies extended as they fly.
“Essentially, it executes a graceful jump but with a seemingly hard landing,” said Tessler in a statement.
“We do not know how often this may happen or whether these leeches use this ability to seek out hosts, but, given that we caught multiple jumps in two short recordings, this behavior may be common for this species,” said Tessler.
Given the wealth of anecdotes from a variety of regions over the years, the duo also posits that it “certainly is possible” that other jumping leech species may exist.
Though the widespread existence of jumping leeches might sound like the plot of a Sharknado-esque class of horror film, it’s not something to worry about – as the researchers mention in the study describing the finding, it’s only a small subset of species within the family of jawed land leeches that might be able to jump.
There’s also more to these spring-like bloodsuckers than meets the eye; their discovery is likely to prove significant for conservation efforts.
“If we can identify how leeches find and attach to hosts, we can better understand the results of their gut content analyses,” Fahmy explained. That can give scientists a better idea of what other kinds of animals are present in the area.
Even leeches themselves might be vulnerable. “Leeches are also often overlooked and understudied, and, as a natural part of the ecosystem, leeches themselves may be in need of conservation protection,” Fahmy added.
The study is published in Biotropica.
