Long, thin black worms are known as horsehair worms, and as the name implies, they resemble hair from the tail of a horse. Horsehair worms are parasitic and are usually found in ponds, pools, water troughs and other watery places.Continue Reading
The parasitic nature of horsehair worms is exhibited as the worm's larvae enters a host species, usually an insect such as a cricket, beetle or grasshopper. The worm feeds on its host until it grows into an adult. The worm exits the host at a time when the insect seeks water, which causes the host to die. The worms are usually found entangled into a ball of worms or alone. Upon leaving a host, horsetail worms are white, but soon turn a brownish black color. While the worm's parasitic nature is discomforting for some, horsetail worms do not grow inside people, birds or plants.
A long-held superstitious belief is that horsetail worms develop from a horse's tail, dropping into the water as a horse drinks from a water trough. However, this is just a myth, as the worms are naturally attracted to small bodies of water. Homeowners may find horsehair worms in pet dishes, toilets or a backyard birdbath. The worms can be removed by hand, net or flushing.Learn more about Worms