Females grow to about one inch, while males grow to about half an inch.
You can find mole crabs by digging a hole in the sand at the very edge of the wash from the waves. Allow water to enter the hole, and swish it around. You should see mole crabs darting through the water before they quickly burry themselves in the sand. With the wash of the incoming waves at their back side, these crabs collect organic matter and very small creatures for food as the water rushes back down the beach over them. Sometimes on Assateague beach, you'll see fishermen gathering mole crabs for bait with meshed wire nets attached to poles.