Imagine strolling through a serene forest, the dappled sunlight filtering through the leaves, when suddenly, you're confronted by an unexpected acrobat–a leaping leech. A video taken by graduate student Mai Fahmy on a field trip may help resolve a long-standing debate among biologists: Can leeches jump? Fahmy, now a conservation biologist at the American Museum of Natural History and Fordham University, captured footage of Chtonobdella leeches in Madagascar performing what she interprets as jumping. This was initially dismissed as a routine observation, but it turned out to be significant evidence in a contentious debate about leech locomotion.
The debate dates back to the 1300s when Islamic traveler Ibn Battuta described “flying leeches” in Sri Lanka. Doubts arose over whether these leeches were actually leaping or just falling from trees. Defining a "jump" is challenging, notes Michael Tessler, a leech specialist, but he suggests it involves active propulsion.
The 2017 video, and a second from 2023, show the leeches exhibiting what appears to be intentional, forceful movements that could be classified as jumping. In one video, a leech coils and then leaps from a leaf to the ground, suggesting a deliberate action rather than a mere tumble. Despite skepticism from some experts who see the motion as ambiguous, others recognize it as a clear jump. While the debate over leech jumping may not be fully settled, Fahmy's video has reignited interest and provided new digital-age evidence for this centuries-old question.
Leaping leeches! Do you think the video finally proves that some leeches can jump, or are they just really good at dramatic falls? Share your thoughts with us on social media!
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