Male adults have massive claws and legs longer than female adults. Females moult their shells during the fall so that they remain soft during mating. [2] The red tips, of course, blend in with the overall color of the crab once it has been cooked, or steamed. [1] Distribution This crab is found from Point Reyes, California to Baja California, Mexico. Distinctive are the antennae that begin between the … Female crab. The diet of juvenile and adult rock crab This event for males happens during the winter months to ensure that their shells are completely firm before the fall. Emily holding a rock crab. Look at the underside of the crab. Females have broader tails that are somewhat heart-shaped. 4.Male blue crabs have blue-colored claw tips while their female counterparts have reddish claw tips. If the abdomen is narrow, it is a male. [1] Males’ bodies grow up to 17 cm (6.5 inches) and females’ bodies up to 11 cm (4.5 inches). 2.Male crabs have a smaller, more triangular, or rocket-shaped underbelly markings compared to the female crabs’ broader or dome-like marking. 3.A female crab usually appears to have some fertilized eggs tucked in-between its body and flap. Crabs will stay in this “pre-mating embrace” until females molt, this can go on as long as two weeks. The first thing a crabber should know is how to tell a male from a female, since it is currently unlawful to keep females. Alternate Name: Pacific rock crab, California rock crab, brown rock crab or just plain rock crab. It takes rock crab shells between 2-3 months to fully harden. However, after the second year, males typi cally grow faster than females, reaching 14 cm by the seventh year in comparison to 8.9 cm for females. Identification: Rock crabs have a wide, hard shell with black-tipped pincers on claw s that are large and smooth. If the abdomen, the flap of shell that folds under from the rear end of the crab, is wide and rounded, the crab is a female. More simply, the bottom of a female crab … Female Crabs: A mature (adult) female blue crab, known as a "Sook," is identified with an inverted "U" or bell-shaped apron and red-tipped claws. Female crabs are called “hens”; male crabs are called “cocks.” Males are very narrow tails and larger claws. The offset molting cycle is the reason female crab molts appear on Oregon beaches earlier than those of males. the first two years, both female and male juvenile rock crab will grow from 1.4 to 4 cm in carapace width. After females molt, male spermatophores are deposited and the embrace often continues for protection of the newly molted female. Male crab on the left and female crab on the right—the females get to go back to the sea; the males, if big enough become dinner. Before mating commences, both male and female rock crabs moult their shell. Underside of a female rock crab—this crab will be tossed back into the ocean. [1] Life history Its life span is at least four years. Crabs, like these red rock crabs, often engage in a premating hug in which the male will wrap his claws and legs around the female. Crabs often show marked sexual dimorphism.Males often have larger claws, a tendency that is particularly pronounced in the fiddler crabs of the genus Uca ().In fiddler crabs, males have one greatly enlarged claw used for communication, particularly for attracting a mate. • Specify gender: Crab gender is easy to distinguish: male crabs (or "jimmies") have a narrow, T-shaped "apron" on the back of their shell, while female crabs ("sooks") have a wide apron. Male crab—see the narrow abdomen.