|Bottom view of crab shows the difference in abdominal width (area) between males (left, narrow) and females (right, wide).||Female crab showing the wide carapace.
Photo by Christian Fischer through Wiki Commons
|Adult crab indicting the hairy claws, notch between the eyes, and the four spines along the carapace.|
Adult mitten crabs are easy to identify because their claws appear to have distinctive thick fur that looks like mittens, a trait for which they are named. The main identifying characteristics are:
- One of very few crabs in North America found in freshwater.
- Adults and juveniles (>1 inch) have furry white-tipped claws that are equal in size. Juveniles with a carapace length less than one inch may not have hair on their claws but those over one inch will have hair.
- Light brown to olive green body (carapace) that is 3 to 4 inches wide in adults. The carapace is smooth and round and has a 4 lateral spines (behind each eye), although the forth spine may be small.
- There is a U-shaped notch in the carapace between the crab’s eyes.
- This crab has four sharp-tipped walking legs and a claw on each side, but lacks a modified swimming leg or paddle (such as those on blue crabs). The legs are over twice the length of the carapace.