Crab from the navel, crab yellow, crab legs, crab paste and other aspects to distinguish male and female.

Bellybutton: Watching the bellybutton is the best way to judge the male and female crabs, because the bellybutton of male crabs is more pointed and triangular, while the belly of female crabs is rounded and shaped as round or oval, and in addition, the eight legs of male crabs are long and fluffy, while the female crabs are only the front two crab legs long and fluffy.

Crab yolk: crabs have orange-red grains of hard crab yolk, crab yolk is the female crab, crab yolk is the ovary and egg cells of the crab. Generally around the ninth month of the lunar calendar, the female crab gonads are mature, the crab meat is the most plump. The male crabs are not.

Crab feet: female crabs crab feet only two legs in front of the growth of fine velvet, while male crabs are different, their eight legs have dense velvet.

Crab paste: the male and female crabs can also be judged by the crab paste, because the crab paste is the male crab's parasympathetic gland and its secretion, which is in the form of semi-transparent jelly, greenish-white in color, and when the male crab matures, the parasympathetic gland is abnormally developed, which will push up the crab shell.

Life of crabs

Most species of crabs are omnivorous. For example, in the intertidal zone of the phase hand crab ingests both plant carrion and eat animal carcasses and small animals. There is also a considerable portion of the crab for carnivorous, such as the pike crab can prey on fish, shrimp and mollusks and so on. A few crabs, such as window crabs, scrape or filter-feeding algae and organic debris. The hard, well-developed jaws of crabs can cut and bite food, and the jaw feet and small jaws can help tear food and deliver it to the mouth.

Food enters the stomach through a short esophagus. The cardia of the stomach is lined with small bone fragments and ridges that form the gastric mill, and is fed with digestive juices secreted by the hepatopancreas, where the food entering the stomach is ground and digested and then passes into the pylorus. The inner wall of the pylorus also has longitudinal ridges of cuticle and many fine prickly hairs, which can filter and clean the food.