“My children found this worm on our driveway in west Tennessee”, writes Heather in her submission regarding the dark brown, segmented worm-like organism pictured below. “Can you help me identify it? Its underside was slightly lighter colored, kind of flattened, and it had a disk-like foot structure (possibly) at one end. Thank you.” Firstly, we want to thank Heather for the fantastic photos. The good lighting and sharp details make our job so much easier, and provides a great resource for others who find similar-looking organisms and want to know what they are. Secondly, whoever’s finger is in the photo below is very lucky, because what Heather’s children found is a leech.

“I saw some of these worms in my cat’s fur, near his butt, but I’m not sure if it’s a parasite or just something from my garden”, writes Th?o in their submission regarding the black, worm-like organism pictured below. “It’s very small, like 5mm long, and very lithe. It’s a pinkish color (it looks darker in the picture). It also died (or dried out) soon after I found it, about 10-15 minutes later. We live in south east Asia, where there’s a tropical climate. Thank you for helping me.” To start with, we have to say that, whatever suggestions we make as to the worm’s identity, Th?o should take them with a grain of salt. The reason for this is that, since this worm was found on Th?o’s cat, it is possible that this is a medical situation.

“I found this in my swimming pool in Mobile, Alabama and I’m wondering if it’s a leech?”, asks Dean in his submission regarding the glossy, black, worm-like creature pictured below. Right off the bat, we have to agree with Dean that this does look like a leech. That said, when we zoomed in on the photo, we saw what looked like part of the creature’s underside, which was a lighter gray color. This made us think about slugs, and the possibility of this being one, though leeches also typically have lighter-colored undersides.

“Are these crane fly larvae, or horse-leeches?” asks Jonathan about the black, worm-like creature pictured below. “I’m in western NC. These guys are about a ¼-inch long. Closest I could find on my own research are the two stated above. Thank you for your time!” After doing some sleuthing of our own, we have always come to similar conclusions as Jonathan – this does resemble crane fly larvae somewhat (though this creature is a little darker than most crane fly larvae), and it does look like a horse leech (though not as slimy, but that could be due to drying out). In addition to these two creatures, we thought this looked like it could be a lugworm or a stick-resembling caterpillar such as the Geometer moth caterpillar.

“What is this worm?” asks this reader in his submission regarding the little, brownish worm pictured below. “Found among algae in the backyard koi pond in northern Illinois. Travels by attaching (perhaps by suction) one end and feeling around with the other. Can stretch to well over 4 times its resting length. Seeks air if submerged. Appears to be slightly flat. Was discovered clinging to hand. Found today. No discernible segmentation.” The thing that caught our eye in the excellent photo our reader sent in is the flattish part at one end of its body, which we assume to be its head. This is likely the part that it uses to “attach” itself to things and move along using, as our reader stated, “suction”. Based on this, as well as its appearance, we are inclined to say that this is likely a leech.

“I found this on our water while I was filling the tub”, states this reader in her query concerning the black worm pictured below. She is not sure if they are leeches or something else, and wants to know if it is harmful.

There is no getting around that leeches get a bad reputation, and we are sure that a couple of our readers might even have grimaced at just reading the word. However, while movies and TV represent leeches through their parasitic relationship to humans, as an entity by themselves, leeches are quite fascinating, and can even be beneficial to humans!

A reader wonders if the creature in this photograph is a dead slug. From the photo we can tell that the creature has black coloration, a smooth exterior, a shape that is bulbous at the head but thins out towards the tail, and is small compared to the $10 bill our reader exhibited for size comparison.

Glossy, black worms were found by this reader in her bed sheets. Having recently moved to Florida, our reader wonders if this is something her dog or her landlord’s cats is bringing in to her home, and hopes that we can tell her what these creatures might be.

We believe the small black organisms our reader found in her pond are either leeches or black fly larvae. Both are similar in appearance, though leeches are slightly bigger, and both are commonly found in ponds. Neither species are considered invasive and neither should damage her pond or cause any problems with the fish!

A reader’s dog accidentally transported a terrestrial flatworm into his kitchen. We are confident that this creature isn’t a threat to him or his dog.

One of our readers found a worm on his couch that we think might be a leech. This creature might have come from his dogs, so we advise him to check for more leeches and take his dogs to the vet if necessary.

We recently heard from two readers, both curious about how to get rid of leeches in cattails and in a pond, respectively. We are happy to provide some information about leech removal for our readers!

We just heard from a reader in Ghana who is interested in information about leeches. Specifically, he would like to know where and how he could sell these leeches.

A reader from South Florida just requested some information about the creatures in a photo she sent us. She thinks they are leeches, but would like us to confirm.

We recently received a photo and question from a reader. She found a creature near her flowerbeds that she thinks might be a slug or leech, and is curious if it could be harmful. The photo shows a small worm-like organism that is shiny black and doesn’t have any appendages or antenna.

A reader wrote to us about a rash her son has in response to what is believed to be a leech bite. She found what looked like a leech on her son’s PE kit after rugby practice, and it was at this time that she noticed his skin reaction, which began as a red spot, and then spread into an itchy rash that covered parts of his body, arms, and legs. The reader has already sought medical help, and her son has been prescribed antibiotics. She only wrote to us to ask if we have ever heard of this sort of skin reaction occurring in response to a leech bite, and also to determine if what she found was in fact a leech.

The annelids are a large phylum of segmented worms; consequently, annelids are commonly called simply “segmented worms.” (They are also, by the way, called “ringed worms,” as the worms’ segmented bodies often make them look like they are wrapped in small rings.) There are over 17,000 species in the annelid phylum, according to recent research, and while this is far less diverse than the phylum Nematoda, which is estimated to have approximately 1,000,000 species, the annelids are still extremely diverse relative to other species of animals.