Horsehair Worm
Scientific Name: Gordius sp. (or other genera in phylum Nematomorpha)
Order & Family: Order Gordioidea, Family Gordiidae
Size: Typically 4 to 14 inches (10 to 35 cm) long, but very thin (about 1 mm in diameter).
Natural Habitat
Found in freshwater environments such as streams, ponds, puddles, and domestic water troughs, often emerging near moisture.
Diet & Feeding
As larvae, they are internal parasites of insects (like crickets and beetles); as adults, they do not eat as they lack a functional digestive system.
Behavior Patterns
They exhibit a parasitic life cycle. Larvae develop inside an insect host and, when mature, manipulate the host to seek water. The worm then bursts out of the host to mate in the water.
Risks & Benefits
They are harmless to humans, pets, and livestock. They are beneficial to ecosystems as they help control populations of insects like crickets, grasshoppers, and cockroaches.
Identified on: 3/26/2026