Crabs are animals of the crustacean species, which are found on the beaches of practically all the countries of the world, river banks, and cliffs, thanks to their great capacity to adapt to any climate. They are hermits by nature, so they prefer to live alone inside rocks or on the banks of rivers or seas.
They are not very good swimmers, so they alternate their stay between the water and the beaches. In the water, the crab moves along the bottom. When it is on land, it moves more easily, knowing cases in which some species have even been able to climb on palm trees.
The body of crabs is covered by a bony shell or exoskeleton, which protects them from attack by predators, which periodically molt or change. Some species take advantage of this change to reproduce since the female at this time is physically softer. Sperm can be stored by the female for a long time, until she decides when is the opportunity to fertilize the eggs, being able to lay 200 thousand eggs.
They have 5 pairs of legs, of which the front 2 are pincers or pincers that help them to hunt their food. Their way of moving is very particular and even funny since they do not do it in a straight line but totally sideways.
The eating habits of crabs are varied and on occasions, they have had to be modified due to the high degree of pollution that exists in the seas and rivers where they live.
As they are mainly carnivorous crustaceans, the feeding preference is based on the taste for fish, other smaller crustaceans, and dead animals, which they find at the water’s edge. With its small legs, it likes to capture algae and other types of organic matter, so its diet is also omnivorous.
The way they use to get their food is through their strong pincers with which they are able to catch their prey and chop them, as they do with animals that are already dead. Once they manage to catch their prey, their pincers function as lethal cages from which it is very difficult to escape once they fall into them.
Despite being hermits, they can share their food with other crabs, particularly the female with whom they are going to mate.
When they are newborns and are released by the female in the form of eggs in the water, they become larvae that move floating thanks to the currents that help them move. At this time, they must feed themselves; however, in many species, the larvae manage to feed on the remains of the yolk of hatched eggs. In this way, they subsist until they are able to capture their prey by themselves.
The digestive system of these crustaceans is made up of a straight tube that works like a grinder, breaking up the food they eat.