The coconut crab, a hermit crab that can grow up to 1 meter in length, is not only the largest terrestrial crab but also the largest terrestrial arthropod. Large, weighing up to 8 kilograms, the coconut crab's shell is hard, there are two strong and powerful giant chelae, is a master of climbing trees, especially good at climbing straight coconut trees, because they can use their strong chelae to peel off the hard shell of coconuts, in order to eat the coconut flesh and so named.
Coconut crabs live in tropical forests near the sea and return to the sea during the breeding season, where their larvae enlarge and grow. Coconut crabs inhabit areas throughout the Indian Ocean and the western Pacific Ocean.
The coconut crab is 1 meter long (from head to leg tip) and weighs 3 kilograms. The carapace and appendicular carapace are calcified and thick, with undulating wrinkles on the surface of the cephalothoracic armor and steppers. The gill area of the cephalothorax is particularly enlarged. Frontal horns triangular, eye scales small. The left cheliped is larger than the right cheliped. Abdominal dorsal and lateral armor are calcified and partially curved under the cephalothorax. Degenerate ventral limb is preserved on one side only. The chelicerae for feeding are one large and one small, and the rest of the body is symmetrical on both sides, making it a hermit crab. Because they don't need to live inside the shells that bind their bodies, adult crabs are very large in appearance and have been recorded as weighing more than seven kilograms and being nearly half a meter long, making them the largest arthropods on land.
Characterized by the body divided into cephalothorax and abdomen. Cephalothorax with developed cephalothoracic armor. The outer limb of the 2nd small jaw is well developed and forms the jaw boat lobe. The first 3 pairs of thoracic limbs are specialized as jaw feet and the last 5 pairs are steppers. Gills in several rows, attached to the base of the thoracic limbs, the lateral wall of the thorax, or the articular membrane between them. The gill area of the cephalothorax is especially enlarged, and the inner wall of the gill cavity is covered with numerous epithelial folds with tufts of blood vessels for terrestrial respiration. The frontal horns are triangular, and the eye scales are small. The first antennal stalk is elongate in all segments, and the end of the antennal whip is thick and slightly rod-shaped, with tactile function. Chelicerae are asymmetrical, the left chelicera is larger than the right chelicera, very stout and powerful, can be used to open the hard coconut shell, feeding on coconut meat. The first and second pairs of footsteps are powerful, with claw-like ends, and can be used to climb trees. The third pair of footsteps are cheliped at the end, and the fourth pair of footsteps are very small, hidden in the gill cavity under the cephalothorax. The abdominal dorsal and lateral armor are calcified, slightly asymmetrical, and partly curved under the cephalothorax. The abdominal limbs are similar to those of hermit crabs, with the degraded abdominal limbs retained on one side only, while those on the other side have disappeared completely. There is a distinct metamorphosis during development, and the newly hatched larvae are unsegmented larvae.
Red-eyed, this crab's body color varies from violet-blue to orange-red between the islands on which it survives. Studies have shown that male coconut crabs are much larger than females.
Larvae are similar to other land hermit crabs in the early stages of reproduction, growing from large-eyed larvae to juvenile crabs that also carry a conch shell that protects the abdomen within it until the abdomen develops a hardened carapace and then breaks away from the conch shell.
Coconut crabs are hermit crabs that grow on many coral islands in the tropical Pacific and Indian Oceans. While hermit crabs normally reside in the spiral shells of gastropods, so their bodies are soft and asymmetrical, the coconut crab has escaped that body-binding conch shell. It seeks out or digs burrows in places like sandy soil or tree roots, so it grows large and sturdy. The body is symmetrical except for the large and small crab pincers that prey on it.