Crabs are a group of crustaceans belonging to the order Decapoda. This order encompasses some 15,000 species, including prawns and prawns.
Crabs are a fundamental piece 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 exactly do crabs eat? We tell you about it in this article on our site.
Characteristics of crabs
These are the main characteristics of crabs:
- Tagmas: Its body is divided into the cephalothorax, which includes the head and part of the thorax, and the pleon, which is what is commonly is known as "tail". However, the latter can be greatly reduced.
- Exoskeleton: Crabs are animals with exoskeletons. It is an external skeleton made of chitin. In addition, it may contain calcium carbonate and be very hardened, forming a kind of shell.
- Muda: With growth, the exoskeleton “outgrows them”. For this reason, like the rest of the arthropods, they detach from it and form a new one.
- Legs: like all decapods, crabs have 10 pairs of legs In the cephalothorax they present 5 pairs. The first ones use them in feeding and the rest are locomotors, that is, they use them to walk. In the pleon they have another 5 pairs of legs that they use to swim.
- Claws: Usually, these animals have a pair of legs turned into claws. These have a defensive and food function. They are usually smaller in females.
- Integumentary gas exchange: crabs have gills associated with the base of their legs, although they are protected by the exoskeleton.
- Gastric mill: it is the stomach of the crabs. These are structures that grind and sift food. Among the characteristics of crabs, this is the most important for understanding their diet.
- Senses: Crabs have sessile compound eyes or eyes on a mobile stalk. They also have sensitive appendages and two pairs of antennae, thanks to which they perceive their surroundings.
- Oviparous reproduction: These animals reproduce by laying eggs. The female transports and incubates them until they hatch.
- Indirect development: a larva known as a “nauplius” hatches from the egg and has a planktonic life. This larva undergoes a process of metamorphosis until it becomes the adult we all know.
- Benthic habitat: With few exceptions, crabs live in riverbeds or on the seabed. This feature can give us a clue about what crabs eat.
What do crayfish eat?
We call the families Astacidae, Parastacidae and Cambaridae crayfish. These crustaceans live at the bottom of rivers and other freshwater bodies, where they hide from predators such as mustelids.
Crayfish feed includes all kinds of organic matter present in the bed They are omnivorous animals and can eat algae, small invertebrates, fish and even carrion. Therefore, they are very important in the recycling of corpses that end up in 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 crabs eat?
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 brachyurans (Brachyura).
Answering what sea crabs eat is not easy, since the diet of these animals depends on the species, its habitat and its way of life. For this reason, we are going to divide the sea crabs into several types according to their diet:
- Carnivorous sea crabs
- Herbivorous crayfish
- Omnivorous crayfish
Carnivorous sea crabs
Carnivorous crabs are normally benthic. Therefore, feed on animals that live on the seafloor, such as small crustaceans and molluscs. However, it is true that some, on an occasional basis, may eat algae.
Here are some examples of carnivorous crabs:
- Crab (Cancer pagurus)
- Blue snow crab (Chionoecetes opilio)
Herbivorous crayfish
These marine animals feed mainly on leaves and shoots of plants, both marine and coastal. These include algae, seagrasses and mangroves. However, to supplement their diet they may eat small invertebrates in very small quantities.
An example of a herbivorous sea crab is the mangrove crab (Aratus pisonii). It is an arboreal crab, which is why some authors consider it to be semi-terrestrial.
Omnivorous crayfish
Omnivorous crabs have a very varied diet, which allows them to adapt very well to different ecosystems. Among the food 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 the water. However, their larvae are aquatic and the females return to the sea to spawn. They also need to live in moist areas to keep their gills hydrated.
Land crabs are usually herbivorous animals. Your 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 (Cardisoma guanhumi)
What do aquarium crabs eat?
Crabs are animals that should live freely and within their ecosystem, not in an aquarium. However, for various reasons, we are sometimes forced to care for a crab that we cannot return home. If this is your case and you wonder what aquarium crabs eat, we are going to give you some clues.
The nutrition of aquarium crabs depends on their habitat, way of life and species. The best thing to do is to Get very good information about your natural diet and try to imitate it Only in this way will we guarantee your 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): This 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 s altwater crab, arboreal in adult stage. It is also omnivorous, although it is It feeds, above all, on mangrove leaves and shoots. It can also eat leaf litter, algae and small invertebrates.
- Rainbow crab (Cardisoma armatum): is a land crab that feeds mainly on leaves, fruits, flowers, beetles and other insects.
- Panther crab (Parathelphusa pantherina): it is a freshwater crustacean and, therefore, a generalist omnivore.
