 Males of the hornyhead chub "Nocomis biguttatus", long, and of the river chub "Nocomis micropogon", long, also build mounds during the reproductive season.They start by clearing a slight depression in the substrate, which they overfill with up to 10,000 pebbles until the mounds are long (in the direction of the water current), wide, and high.Females lay their eggs among those pebbles.