Earthworms: Oligochaeta

Physical characteristics: The river worm has a dark brown body 4.7 to 7.8 inches (120 to 200 millimeters) in length. It has small pairs of lengthwise grooves underneath the body.

Geographic range: The river worm is found in the Central United States, including Iowa, Illinois, Missouri, Kansas, and Nebraska.

Habitat: River worms live in fine soils washed up along river banks and beneath stands of silver maples.

Diet: They burrow through leaf litter and just below the soil surface, eating detritus buried in river mud.

River worms live in fine soils washed up along river banks and beneath stands of silver maples. (Illustration by Bruce Worden. Reproduced by permission.)

Behavior and reproduction: Nothing has been written about their behavior. River worms have both male and female reproductive organs.

River worms and people: River worms are collected and sold for fish bait. This species is more tolerant of summer heat than other bait species.

Conservation status: This species is not considered endangered or threatened. However, exotic species brought in as fish bait have become established along some rivers and streams, crowding out the river worm. ∎