Yep…Leeches! This summer, as Dr. Bronwyn Williams and I were planning our annual excursion to New England to collect crayfish for an ongoing pet project of mine, I was told Anna Phillips, Research Zoologist and Curator of Parasitic and Gummi Worms1, at the National Museum of Natural History, Smithsonian Institution, wanted to join us, because she wanted to catch leeches. Yep…leeches! Don’t they usually just catch you? Like most people, my first response was “Ew! Leeches!” All I could think about was that scene in the movie “Stand by Me” where the kid pulls a big fat leech out of his underwear. Yeah…maybe not. Truth be told, initially I wasn’t exactly thrilled by the prospect.
But, let’s back up a minute.
I’m a 50-something year old Paleontologist, who has spent the bulk of my adult life collecting fossils in dry, leech-free environments. Ticks, sure. Chiggers…itchy, but I’ve had more than my share. Leeches…hmmm? I’ve never had a leech on me, so this was going to be an interesting challenge. To prepare I managed to convince myself that the leeches we were about to sacrifice ourselves to were medicinal, so they couldn’t be all bad. Heck…they might even be good for me. Having jumped through that mental hurdle, suddenly, I was all in. Even wrote the permit application, because it turns out if you actually WANT to collect leeches (for scientific research) you need a permit… who knew?
From the moment we picked Anna up at the train station I bombarded her with questions like…How does one catch a leech? Is a menstruating woman more likely to attract leeches than say a non-menstruating woman? What about children, wouldn’t they make better leech bait? Should I pick a scab to chum the waters with a bit of blood? Because now I really, really wanted the leeches to find me attractive.
As it turns out, there are approximately 700 different species of leeches. Who knew? True leeches, in the subclass Hirudinea, can be divided into two groups, Rhynchobdellida which lack jaws but have a proboscis, and Arhynchobdellida which lack a proboscis and may or may not have jaws with teeth. There are freshwater leeches which include medicinal leeches, marine leeches, and terrestrial leeches. ACK!!! Leeches everywhere! The NMI Collection has examples of most of these. There are turtle leeches (Placobdella), snail leeches (Helobdella), insect eating leeches (Erpobdellidae), fish leeches (Piscicolidae), horse leeches (Haemopsis), etc…so many leeches, listing them makes me feel a bit like Bubba from “Forest Gump.”
We were specifically trying to catch North American medicinal leeches, Macrobdellidae, which are blood sucking leeches, but aren’t as “medicinal” as the European medicinal leeches (Hirudinidae). Blood-letting by leeches was thought to balance one’s humors, if you had a rash or fever, a bit of leech therapy was just the ticket because you had too much blood and probably a bad sense of humor. Leeches, were so commonly used in the 1800-1900’s that people actually farmed them. However, North American “medicinal” species were not as commonly used as European species. Colonists would actually send back to Europe for leeches rather than using local populations. According to Wikipedia2, in 1831 the Manchester Royal Infirmary used 50,000 leeches per year. These days, leeches are used to promote blood circulation for skin grafts and for things like finger reattachment, to treat osteoarthritis, and varicose veins.
But I digress. Our mission was just to catch leeches, lots of leeches. To do this we had to dance! Ooh! Dances with Leeches! Sure, you could bait traps with liver or some other bloody meat, but where’s the fun in that? It doesn’t matter if you have no sense of rhythm or are just generally uncoordinated like me, it’s the vibrations in the water that seem to attract the leeches. Now, I’m thinking we should’ve gotten some huge speakers and turned up the bass! “Tremors”, anyone? Also, there didn’t seem to be any particular beat the leeches preferred. You could samba, salsa or just generally flail about, then stop, and do yoga poses while trying to see if you had any leeches on you. Then dance, dance, dance! We spent about a half hour at each site.
Low flow streams and stagnant ponds were great places to practice our leech attracting dance moves. Though we never figured out the ideal leech habitat, ponds or streams with saw grass or cut grass, lily pads, shade and a scummy bottom seemed to yield more leeches. It took a bit, but I finally attracted leeches, even had one latch on between my toes and feed. Yay! Let the blood-letting begin! I never felt it attach, only noticed it when it started to itch, which leech bites sometimes do, but that doesn’t last long. Mostly, we’d see them before we felt them and could pluck them off before they started to feed, which kept the blood loss to a minimum.
Because leech catching is a ridiculous thing to do… the more the merrier. My sister, Janet, and a former student of Megan McCuller’s (NMI Unit Collections Manager), Emily Haggett, joined us for the big dance. We caught leeches at most of the sites we went to, but there were two sites that were particularly leech-laden. One was a pond where we collected medicinal leeches, turtle leeches, snail leeches and insect eating leeches. That’s a lot of leeches. By the way, what is a group of leeches called? A lecher of leeches? A bevy of blood-letters? A dispatch of de-sanguinators?
The other really good leech site (last site of our trip) was actually supposed to be a crayfish site, but when the leeches started appearing as a result of Anna and Bronwyn stirring up the crayfish, it turned into a big-old leech fest3. Even though I was apprehensive at first, I have to say, dancing with leeches was probably the most fun and entertaining thing I’ve done in a very long time. (I really should get out more…) Call me crazy, I know. But what can I say? Maybe it was the people involved. Maybe it was the blood loss making me giddy. Or maybe, just maybe, it was the leeches.
by Trish Weaver.
1 Anna Phillips is not technically the Curator of Gummi Worms, but as someone ought to be, it might as well be her. This notion comes from a conversation Anna had with Bronwyn’s seven year old nephew, who asked “do you study real worms, or Gummi worms? because Gummi worms are a real thing too.”
2I used a lot of different websites, most of which I can’t remember, to learn more about medicinal leeches and you can too. Just Google medicinal leeches and have fun.
3All leeches collected on this trip have been deposited at the Smithsonian Institution a.k.a.National Museum of Natural History (USNM), where if you were to sample the DNA within the leeches you might just find a small part of me.
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