CRAB
* They live in all the world's oceans, in fresh water, and on land, are generally covered with a thick exoskeleton and have a single pair of claws.
* Many other animals with similar names – such as hermit crabs, king crabs, porcelain crabs, horseshoe crabs, and crab lice – are not true crabs.
* Crabs are generally covered with a thick exoskeleton, composed primarily of highly mineralized chitin, and armed with a single pair of chelae (claws).
* Crabs are found in all of the world's oceans, while many crabs live in fresh water and on land, particularly in tropical regions.
* Crabs vary in size from the pea crab, a few millimetres wide, to the Japanese spider crab, with a leg span of up to 4 metres (13 ft).
*About 850 species of crab are freshwater, terrestrial or semi-terrestrial species; they are found throughout the world's tropical and semi-tropical regions.
* They were previously thought to be a monophyletic group, but are now believed to represent at least two distinct lineages, one in the Old World and one in the New World.
BEHAVIOUR
*Carpilius convexus consuming Heterocentrotus trigonarius in Hawaii
Crabs typically walk sideways (a behaviour which gives us the word crabwise), because of the articulation of the legs which makes a sidelong gait more efficient. However, some crabs walk forwards or backwards, including raninids, Libinia emarginata and Mictyris platycheles. Some crabs, notably the Portunidae and Matutidae, are also capable of swimming, the Portunidae especially so as their last pair of walking legs is flattened into swimming paddles.
*Crabs are mostly active animals with complex behaviour patterns. They can communicate by drumming or waving their pincers. Crabs tend to be aggressive towards one another, and males often fight to gain access to females.
* On rocky seashores, where nearly all caves and crevices are occupied, crabs may also fight over hiding holes. Fiddler crabs dig burrows in sand or mud, which they use for resting, hiding, and mating, and to defend against intruders.
* Crabs are omnivores, feeding primarily on algae, and taking any other food, including molluscs, worms, other crustaceans, fungi, bacteria and detritus, depending on their availability and the crab species.
* For many crabs, a mixed diet of plant and animal matter results in the fastest growth and greatest fitness. However, some species are more specialised in their diets. Some eat plankton, some eat primarily shellfish like clams, and some even catch fish.
* Crabs are known to work together to provide food and protection for their family, and during mating season to find a comfortable spot for the female to release her eggs.
* They live in all the world's oceans, in fresh water, and on land, are generally covered with a thick exoskeleton and have a single pair of claws.
* Many other animals with similar names – such as hermit crabs, king crabs, porcelain crabs, horseshoe crabs, and crab lice – are not true crabs.
* Crabs are generally covered with a thick exoskeleton, composed primarily of highly mineralized chitin, and armed with a single pair of chelae (claws).
* Crabs are found in all of the world's oceans, while many crabs live in fresh water and on land, particularly in tropical regions.
* Crabs vary in size from the pea crab, a few millimetres wide, to the Japanese spider crab, with a leg span of up to 4 metres (13 ft).
*About 850 species of crab are freshwater, terrestrial or semi-terrestrial species; they are found throughout the world's tropical and semi-tropical regions.
* They were previously thought to be a monophyletic group, but are now believed to represent at least two distinct lineages, one in the Old World and one in the New World.
BEHAVIOUR
*Carpilius convexus consuming Heterocentrotus trigonarius in Hawaii
Crabs typically walk sideways (a behaviour which gives us the word crabwise), because of the articulation of the legs which makes a sidelong gait more efficient. However, some crabs walk forwards or backwards, including raninids, Libinia emarginata and Mictyris platycheles. Some crabs, notably the Portunidae and Matutidae, are also capable of swimming, the Portunidae especially so as their last pair of walking legs is flattened into swimming paddles.
*Crabs are mostly active animals with complex behaviour patterns. They can communicate by drumming or waving their pincers. Crabs tend to be aggressive towards one another, and males often fight to gain access to females.
* On rocky seashores, where nearly all caves and crevices are occupied, crabs may also fight over hiding holes. Fiddler crabs dig burrows in sand or mud, which they use for resting, hiding, and mating, and to defend against intruders.
* Crabs are omnivores, feeding primarily on algae, and taking any other food, including molluscs, worms, other crustaceans, fungi, bacteria and detritus, depending on their availability and the crab species.
* For many crabs, a mixed diet of plant and animal matter results in the fastest growth and greatest fitness. However, some species are more specialised in their diets. Some eat plankton, some eat primarily shellfish like clams, and some even catch fish.
* Crabs are known to work together to provide food and protection for their family, and during mating season to find a comfortable spot for the female to release her eggs.
No comments:
Post a Comment