Researchers have discovered something completely new: leeches can leap by pulling themselves up from leaves in the lush jungles of Madagascar.
This amazing find finally settles a debate that has been going on for hundreds of years about how well bloodsuckers could jump. This behavior has been discussed for years but has never been properly documented until now.
(Photo: WikimediaCommons/ Bernard DUPONT )
How Leaping Leeches Work
Mai Fahmy, a researcher who now works at the American Museum of Natural History, saw this activity for the first time in Ranomafana National Park in Madagascar in 2017. She got a video of a leech looking for a host and then jumping off a leaf. This fantastic movie and a video from 2023 that shows similar acrobatics have been published in the journal Biotropica.
Fahmy said that even though they were in Madagascar getting leeches for blood meal analysis, they were under a lot of pressure to get another video to back up what they said in their paper. People have said that land leeches, especially the species Chtonobdella fallax, jump for a blood-filled host, and the team's results back this up.
People had thought about leeches jumping since the 14th century when traveler Ibn Battuta wrote about how Sri Lankan leeches behaved similarly. However, scientific doubt has been the norm since the middle of the 20th century and is still strong today.
Michael Tessler, an invertebrate biologist at the American Museum of Natural History and Medgar Evers College, said that very well-trained people had been telling stories about jumping leeches for hundreds of years. People didn't start studying leeches seriously until the 1800s and early 1900s. Almost every scientist who spent time with them said they couldn't jump.
Video footage shows that leeches attach their back sucker to a surface, like a leaf, coil their bodies backward, and then jump forward. Like a cobra striking, this action moves the leeches toward possible hosts.
Tessler thought the quick burst of movement could allow the leeches to land on or near prey that wasn't paying attention. This new information shows that jumping might be more common in land-dwelling leeches than was thought before.
Are leech bites deadly?
Leech bites are usually annoying and not very dangerous to your health, but sometimes they can be. There is a small chance that someone could die from a blood infection or a huge number of leech bites. For example, some troops were killed during Napoleon's march across Egypt in 1799 after drinking water that was tainted with leeches and made it hard for them to breathe.
Leeches usually feed for twenty to thirty minutes before they come off. Bite wounds can bleed for up to 10 hours and sometimes even longer. A single bite is usually not very bad, but several bites can lead to much blood loss. There have been cases like the man in Turkey who got 130 leech bites and developed anemia and heavy bleeding. The anticoagulants in leech saliva stop blood from clotting, which is very bad for your health.
Leeches can also spread sickness. Since leeches don't have an immune system to clean the food they eat, if they spit blood into a cut, it can spread infections. People have said that medicinal leeches can spread diseases like syphilis and erysipelas.
Also, leeches can enter body openings, attaching themselves inside and causing major health problems. Lice, for instance, can get into the eyes, ears, noses, throats, and even the genital and urinary systems. This can lead to signs like bleeding that doesn't make sense, fever, vomiting, and trouble breathing.
The discovery of leaping leeches in Madagascar answers a long-standing scientific question and shows how much more study is needed to understand these exciting animals' behavior and biology fully. Fahmy said there is still much to learn about leeches' biology, natural history, and habits. He said they are mysterious. The journal Biotropica released this ground-breaking study that gives us new information about the complicated world of terrestrial leeches.
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