Surprise! (video)

Surprise that came in with Frog Eggs...

 With the permission of the Forest Preserve, I've been borrowing some frog eggs in order to capture time lapses of their development (a project that will be posted to the blog when complete).  Tadpoles are returned to the pond within 24 hours of hatching.  Every time I bring some eggs home though, I am amazed, once again, at the prolific variety of life supported in the pond. Even though I am bringing home just a couple of dead reeds with frog eggs on them, or a dead leaf or two from the bottom of the pond, there are always surprise guests that show up in my videos or time lapses. Case in point: I brought home a dead leaf and a small plant stem with some spring peeper eggs on them, set up my time lapse and was about to start it when I was startled by the critter above undulating through the tank.

Yes, it's a leech. This particular leech is about half an inch long when contracted and probably easily over an inch when stretched out. It has two means of locomotion: (1) It has a sucker at each end of its body -- one on the head where the mouth is located and one at the tail end. With a motion similar to an inch worm it will anchor its tail suction cup and stretch itself out and anchor the head then contract and pull the tail up to the head and do it again. (2) Its body is flattened rather like a ribbon and it can swim through the water by forming vertical waves passing through its body from front to back to propel itself forward, surprisingly fast.  The video below provides examples of both types of movement, including a slow motion segment of the undulations as it swims.

There are about 700 known species of leeches in the world, about 65 in the United States. All prey on other animals, but many are very particular, preying specifically for example on amphibians or ducks or turtles. Some specialize in eating amphibian eggs. I don't yet know which kind this one is, though my guess would be that it involves frogs or frog eggs...

Leeches will not be my favorite residents of the pond, but like everything else, they have their place and play their role. Leeches that live in ephemeral ponds spend the dry months dormant down in the mud.





I found the following resource particularly informative and with a pleasant sense of humor, I hope you enjoy it also:

https://uwm.edu/field-station/leeches-revisited/

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