The river crab pincers have hairs because river crabs feed in water, and their food is plankton in running water, so they use the hairs on their pincers to net food in running water, or to measure the current for use. Hairy crabs are omnivorous, eating everything from grass roots to rotting fish, and the fluffy hairs are similar to sound waves from bats, which help them distinguish between enemies and food.

River crab pincers have hairs because they feed in the water, and the food is plankton in the running water, so they use the hairs on the pincers to net food in the running water, or to measure the current for use. Hairy crabs are omnivorous, eating everything from grass roots to rotting fish, and the fluffy hairs are similar to sound waves from bats, which help them distinguish between enemies and food.