The dense rainforest of Madagascar, known for its unique wildlife, has revealed yet another secret. During two separate expeditions, scientists captured astonishing footage of leeches defying gravity with acrobatic leaps.
These aren’t just leeches. They belong to the genus Chtonobdella, a group known for their usual sluggish crawl. But these creatures have been filmed coiling their bodies like tightly wound springs before launching themselves into the air, soaring with unexpected grace.
Drs. Mai Fahmy and Michael Tessler from the American Museum of Natural History, Fordham University, and City University of New York Medgar Evers College, published footage in Biotropica providing the first evidence of these jumping leeches.1
This behavior is not entirely new to the animal kingdom, as other worm-like invertebrates have been known to jump. But it has never been definitively documented in leeches. For years, tales of leaping leeches were whispered among naturalists and dismissed as mere folklore. Back in 1881, renowned biologist Ernst Haeckel described observing this surprising ability in leeches during his visit to Sri Lanka: they could not only crawl but also “spring to reach their victim.”2
Now, with undeniable video evidence, the myth has become a reality.
What do leeches have to do with humans? Well, leeches are blood sucking parasites that attach to unwary passers-by. They bite and deliver an anti-clotting agent that allows them to feast on their host over several days. Leeches can be problematic, they can carry viruses (like HIV and hepatitis B) and bacteria, sometimes spreading infections to humans.3 It’s not all bad though, leeches have been a tool in traditional western medicine dating back to antiquity. Doctors would use leeches to remove excess pooled blood, treat bruising and to perform bloodletting. In modern times, similar to maggots, some doctors have found that (farmed, clean) leeches are a great tool to help post operative bruising. Typically, leech bites can happen while bathing or drinking unfiltered water or while swimming in contaminated water, but now they latch on by jumping from trees.3
So if you’re planning a trip to Madagascar, you might want to pack an umbrella.
Jumping with the leeches
The star of these videos is the Chtonobdella fallax, a common Madagascan leech. Researchers Fahmy and Tessler captured footage of the leeches coiling their bodies before launching themselves into the air, reminiscent of a backbending cobra or a spring being released.
This remarkable behavior, a stark contrast to the leeches’ typical slow, inching movements, has never before been scientifically recorded. The footage reveals the leeches soaring through the air with their bodies fully extended before landing, a sight that has stunned and intrigued the scientific community.
“Essentially, it executes a graceful jump but with a seemingly hard landing,” says Dr. Tessler in a recent press release.
The frequency and purpose of their aerial acrobatics remain a mystery. Do they use these jumps to ambush unsuspecting hosts? Or perhaps to escape predators? The scientists speculate that, given the number of observed jumps, this behavior could be a regular part of their repertoire.
“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.
This revelation opens a new chapter in our understanding of leech behavior and has significant implications for conservation efforts. Leeches, often seen as nothing more than blood-sucking parasites, play a crucial role in studying biodiversity. The contents of their stomachs provide a snapshot of the animals they’ve fed on, giving scientists valuable information about the ecosystem. Understanding how leeches find and attach to their hosts could enhance the accuracy of these studies.
More than just research tools, leeches are an integral part of Madagascar’s delicate ecological balance. By shedding light on their fascinating behaviors, scientists hope to ensure these creatures, often overlooked and misunderstood, receive the conservation attention they deserve.
References
- Fahmy, M. and Tessler, M. (2024) ‘A jumping terrestrial leech from Madagascar’, Biotropica [Preprint]. doi:10.1111/btp.13340.
- A visit to ceylon (2000) A Visit to Ceylon, by Ernst Haeckel, Chapter 6. Available at: http://www.biolib.de/haeckel/ceylon_e/chapter_06.html (Accessed: 22 June 2024).
- Conley K, Jamal Z, Juergens AL. Leech Bite. [Updated 2023 Jul 24]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK518971/#
