Horsehair worm
Scientific Name: Nematomorpha
Order & Family: Order: Gordioidea; Family: Various (e.g., Gordiidae)
Size: 10 to 35 centimeters (4 to 14 inches) long, but only 1 to 3 millimeters (0.04 to 0.12 inches) wide.
Natural Habitat
Freshwater environments such as ponds, streams, puddles, and livestock troughs; often found on damp ground or nearby vegetation.
Diet & Feeding
Larvae are internal parasites of insects (such as crickets and beetles); adults do not eat as they lack a functional digestive system.
Behavior Patterns
They are known for their parasite-induced 'mind control' where they cause their insect host to seek out water. Once the host reaches water, the adult worm emerges to mate and lay eggs.
Risks & Benefits
They are harmless to humans, pets, and plants. They are beneficial to the ecosystem by helping to naturally control insect populations, particularly crickets and grasshoppers.
Identified on: 3/17/2026