A little-known debate has persisted among scientists for "well over a century" — can leeches jump?
New video taken on the jungle floor in Madagascar, off the south-east coast of Africa, may finally provide an answer.
The footage, released alongside a study in the journal Biotropica this week, appears to show a land-dwelling leech "intentionally jumping" off a leaf.
Postdoctoral researcher at Fordham University Mai Fahmy, who co-authored the study, captured the video in Ranomafana National Park 2017.
"First, the leech takes a preliminary, short jump across a section of the leaf it is perched on," the report said.
"The leech has a clear set-up for the jump, in which its body coils back, much like a cobra preparing to strike.
"This seemingly builds up, and likely maximises, potential energy.
"It is not clear whether the leech intended to clear the edge of the leaf during the first attempt, in which case it may be a spatial miscalculation on the part of the leech."
The second jump captured in the clip, according to researchers, is "a much larger feat".
"The leech can be seen going through the same coiling back set-up, followed by a true jump or leap … the leech does not tumble.
"Essentially, it executes a graceful jump but has a seemingly hard landing."
A second video also captured by Dr Fahmy showed two leeches "briefly interacting with each other" on a leaf before one jumped to the ground.
"Our observations establish that at least two terrestrial leeches possess the musculature, coordination and inclination to execute a jump," the report said.
"We believe this is the first convincing evidence that leeches can jump and do so with visual energy expenditure (in contrast to falling from above).
"This counteracts arguments that all leeches do not jump, but simply attach to passers-by from shrubs or occasionally drop from above without any propulsion."
The peer-reviewed report also noted that, despite the video, many stories of leeches "jumping" throughout history could be a case of them going undetected until they had reached the waist or neck of the host.
Most leeches use an inchworm-like movement to travel, and latch onto objects that brush against them.
The leeches shown in the video have been identified as a type of Chtonobdella leech, a two-jawed species found across Madagascar and the South Pacific Islands.
Dr Fahmy told the New York Times that leeches could become "pretty frantic" when baited with a nearby bag of blood.
"And when there are a lot of leeches, it can be kind of overwhelming in the field to notice that you are being pursued so intensely by so many little guys," she said.
