The largest crab is the Giant Killer Crab.

The largest crab in the world is known as the Giant Killer Crab, which can reach a length of four point two meters and a weight of about forty pounds, making it the largest crab in the world. The scientific name of the killer crab is called the giant crabs, because they usually mainly eat corpses for a living, so it is also known as necrophagous crabs.

Because of people's exaggeration as well as rumors, it became the killer crab. People are also expected to break out in a cold sweat when they hear this title.

But going to the whole point is actually not so aggressive, but although their power is not a threat to humans, but can make the sea sharks scared. They would use their crab legs to chase down prey, and then use their hard pincers to stab the sharks.

Morphological features

The giant crabs weigh 16 to 20 kilograms, with an average length of 3 meters, and an open span of up to 4.2 meters. The body has a very sensitive vibration organ, can distinguish the moving objects on the surface of the sea, and this crab in the water activities are exceptionally flexible and agile.

The giant crabs body shape is pike-shaped, pointed at both ends, 10 crab claws both long and sharp, especially the pair of chelae like steel pincers, very strong and powerful, all the claws unfolded, can cover a range of 3 meters in diameter.

The giant crabs belong to the short-tailed lower order, although also known as the crab, but with the short-tailed suborder in the real crab is different. The body of the crab is divided into a cephalothorax and an abdomen. The dorsal surface of the cephalothorax is covered with cephalothoracic armor, and the frontal area is centrally covered with the first and second pairs of antennae, with stalked compound eyes on the outside. The mouthparts consist of 1 pair of large jaws, 2 pairs of small jaws and 3 pairs of jaw feet.

The cephalothorax is flanked by 5 pairs of thoracic pedipalps. The abdomen is reduced, flattened, and curved over the ventral surface of the cephalothorax. Male abdomen is narrow and long, mostly triangular, with only the first two pairs of appendages deformed into copulatory apparatus; female abdomen is broad, with one pair of double-branched appendages on each of segments 2-5, densely covered with bristles for holding eggs.

The Japanese giant spider crab is not the heaviest, but it is the most famous arthropod. The calcified carapace is only about 37 centimeters long, but when stretched, a chelicerae can be nearly 4 meters long in addition to the body. The dorsal armor is subrounded and pear-shaped. The head is narrower, with the cephalothoracic armor more than 40 centimeters wide, and the head tends to be wider in females, although the abdomen is slightly smaller than in males.

Spines and thick, short nodules (growths) cover the carapace, and the color of the shell ranges from dull orange to light brown. They have a very mysterious coloration and are unable to change color for life. The dorsal armor extension on the head is shaped as two elongated spines that protrude partially from the middle of each eye. The anterior part of the muzzle forms a spur.

The growth of the carapace tends to continue throughout adulthood, but the walking claws and chelicerae greatly extend the growth period. Spider crabs are well known for having long, thin feet that resemble armor at the cephalothorax, and feet that are also orange, but covered with speckled and mottled orange and white. The giant crabs simply walk in an inward curved and raised position.

These assist the creature in picking up or grasping objects while climbing, while preventing rolling off. Adult males have chelae that are much longer than any of the walking legs, with the left and right chelae having equal dimensions. Females have chelae that are shorter than the other walking legs. Their legs are long but fragile. One study reported that nearly three-quarters of all mitten crabs are missing at least one limb.

This is because, with long limbs, the body that joins them to the organism is less secure and can be easily dislodged due to hostiles and fishing nets hanging on.