A claw from a lady crab.
A claw from a lady crab.
Irene H. Stuckey, courtesy of R.I. Natural History Survey

Lady Crab (Ovalipes ocellatus)

Alternate common names: Calico Crab, Sand Crab.
Color: White to yellowish grey, with reddish purple mottled spots over body and claws.
Size: 2 to 4 inches wide, 1 to 2 inches from front to back.
Habitat: Throughout the Bay, on sandy or muddy bottoms, often in shallow waters.
Seasonal appearance: All year.

Description

The lady crab is a brightly colored, aggressive, swimming crab. In the water and under direct sunlight, this crab's coloring appears iridescent. The species is called the lady crab because of the beautiful color patterns on the shell, although there are male lady crabs as well as females. The sharp, powerful pinchers are whitish in color with purple-spotted tips and jagged teeth. The last pair of legs are modified into paddles and are adapted for swimming. Three sharp points are present between the eye sockets of the lady crab, as well as five sharp points along the carapace that turn toward the eye sockets. The number of points along the carapace helps to distinguish this crab from the similar-looking blue crab. The tail of this crab is tucked underneath the body and lies against the abdomen. The tail of the female lady crab is shaped like a rounded triangle, while the tail of the male is pointed and narrow.

Drawing of a lady crab.
Drawing of a lady crab.
Courtesy: Save The Bay

Life History and Behavior

Female crabs use their tails to cover their eggs. Young crabs hatch in the early summer months, beginning their lives as zooplankton, and they settle to the bottom by early fall.

Lady crabs are known for their aggressive disposition and sharp claws. This crab is often seen partially buried in sand with only its eyestalks protruding. The lady crab will dart out of its hiding place using its powerful paddles to swim after its prey. Like most other crabs, lady crabs are scavengers, eating both dead and live fish, crabs, and other invertebrates. They can rapidly consume small clams and prey upon hard clams. Oyster toadfish, tautog, striped bass, American lobsters, and other crabs prey upon lady crabs.

Special Notes


Adapted from The Uncommon Guide to Common Life on Narragansett Bay. Save The Bay, 1998.