What do crabs eat?

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Crabs are a group of crustaceans belonging to the order Decapoda. This order includes some 15,000 species, including prawns and prawns..

Crabs are a fundamental part of their ecosystems, both for being great consumers and for being the favorite prey of many aquatic carnivores. In addition, as we will see, some are essential for the recycling of organic matter. But, ¿what do crabs eat exactly? We tell you about it in this AnimalWised article.

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  1. Characteristics of crabs
  2. What do crayfish eat?
  3. What do sea crabs eat?
  4. What do land crabs eat?
  5. What do aquarium crabs eat?

Characteristics of crabs

These are the main characteristics of crabs:

  • Tagmas: its body is divided into cephalothorax, which includes the head and part of the thorax, and the pleon, which is what is commonly known as "tail". However, the latter may be greatly reduced.
  • Exoskeleton: crabs are animals with exoskeletons. It is an external skeleton composed of chitin. In addition, it can have calcium carbonate and be very hard, forming a kind of shell..
  • Change: with growth, the exoskeleton "is too small ". For this reason, like the rest of arthropods, they detach from it and form a new one.
  • Legs: like all decapods, crabs they have 10 pairs of legs. In the cephalothorax they present 5 pairs. The former use them in food and the rest are locomotives, that is, they use them to walk. In the pleon they have another 5 pairs of legs that they use to swim.
  • Tweezers: these animals usually have a pair of legs turned into pincers. These have a defensive and alimentary function. They are usually smaller in females.
  • Integumentary gas exchange: crabs have gills associated with the base of their legs, although protected by the exoskeleton.
  • Gastric mill: it is the stomach of crabs. These are structures that grind and sift food. Among the characteristics of crabs, this is the most important for understanding their diet.
  • SensesCrabs have sessile compound eyes or on a movable peduncle. They also have sensitive appendages and two pairs of antennas, thanks to which they perceive their environment..
  • Oviparous reproduction: these animals reproduce by laying eggs. The female transports them and incubates them until they hatch.
  • Indirect development: a larva known as "nauplius " hatches from the egg, which has a planktonic life. This larva undergoes a process of metamorphosis until it becomes the adult that we all know.
  • Habitat benthicor: With few exceptions, crabs live on river beds or on the seabed. This feature can give us a clue as to what crabs eat..

What do crayfish eat?

We call crayfish the families Astacidae, Parastacidae and Cambaridae. These crustaceans live at the bottom of rivers and other bodies of fresh water, where they hide from predators such as mustelids..

The crayfish diet includes all kinds of organic matter present in the bed. They are omnivorous animals and can eat algae, small invertebrates, fish, and even carrion. For this reason, they are very important in the recycling of corpses that go to the bed, avoiding their accumulation..

Examples of crayfish

Here are some examples of crayfish:

  • European crayfish (Austropotamobius pallipes)
  • American red crab (Procambarus clarkii)

What do sea crabs eat?

Sea crabs are a very diverse group of crustaceans. In it we can find many types of crabs, such as hermits (Paguroidea), spiny lobsters (Palinuridae) and most of the braquiuros (Brachyura).

Responding to what sea crabs eat is not easy, since feeding these animals depends on the species, its habitat and its way of life. For this reason, we are going to divide sea crabs into several types according to their diet:

  • Carnivorous sea crabs
  • Herbivorous sea crabs
  • Omnivorous sea crabs

Carnivorous sea crabs

Carnivorous crabs are normally benthic. Thus, they feed on animals that live on the seabed, like small crustaceans and mollusks. However, it is true that some may occasionally eat seaweed..

Here are some examples of carnivorous crabs:

  • Crab (Cancer pagurus)
  • Blue Snow Crab (Chionoecetes opilio)

Herbivorous sea crabs

These marine animals mainly feed on plant leaves and shoots, both marine and coastal. These include algae, seagrass, and mangroves. However, to supplement their diet they can eat small invertebrates in very small quantities..

An example of a herbivorous sea crab is the mangrove crab (Aratus pisonii). It is a tree crab, which is why some authors consider it semi-terrestrial.

Omnivorous sea crabs

Omnivorous crabs have a very varied diet, which allows them to adapt very well to different ecosystems. Among the diet of the crabs belonging to this group we can find small invertebrates, algae and even carrion.

Some examples of omnivorous sea crabs are:

  • Blue crab (Callinectes sapidus)
  • Coconut crab (Birgus latro)

What do land crabs eat?

Land crabs are those that spend much of their life cycle out of water. However, their larvae are aquatic and the females return to the sea to spawn. In addition, they need to live in humid areas to keep their gills hydrated..

Land crabs are usually herbivorous animals. Their diet is based on fruits and leaves. However, they often feed on carrion and small invertebrates as well..

Examples of land crabs

Here are some examples of land crabs:

  • Red land crab (Gecarcinus lateralis)
  • Blue land crab (Guanhumi cardisoma)

What do aquarium crabs eat?

Crabs are animals that must live in freedom and within their ecosystem, not in an aquarium. However, for various reasons, we are sometimes forced to take care of a crab that we cannot return to its home. If this is your case and you wonder what aquarium crabs eat, we are going to give you some clues.

The diet of aquarium crabs depends on their habitat, way of life and species. The best is learn very well about their natural diet and try to imitate it. Only in this way will we guarantee its correct nutrition. If there are still doubts, it is very important to go to a professional who can advise us.

Examples of aquarium crabs

Some examples of crabs widely used in aquariums are:

  • European fiddler crab (Uca tangeri): it is a semi-terrestrial crustacean. It is omnivorous and feeds mainly on nutrient-rich sediments, such as microalgae. Marsh plants, litter and carrion can also be found in their diet..
  • Red land crab (Neosarmatium meinerti): it is a saltwater crab, arboreal in adult stage. It is also omnivorous, although it feeds mainly on mangrove leaves and shoots. It can also eat leaf litter, algae and small invertebrates.
  • Rainbow Crab (Cardisoma armatum): it is a land crab that feeds mainly on leaves, fruits, flowers, beetles and other insects.
  • Panther crabParathelphusa pantherina): it is a freshwater crustacean and therefore a generalist omnivore.

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