One of the 22 crabs on WAnimals

Malacostracans · Decapoda · Coenobitidae

Coconut Crab

Birgus latro

Vulnerable

It faces a high risk of extinction in the wild over the medium term. See full glossary

The coconut crab is a decapod crustacean of the family Coenobitidae, the only one in its genus; it is the heaviest land arthropod known. The coconut crab is a hermit crab whose characteristic ability is to open coconuts with its powerful claws in order to feed on their contents.

Weight

up to 4 kg

Size

20 cm – 40 cm

Lifespan

60 years

Diet

Omnivore

Combines animal and plant food depending on availability.

Activity

Nocturnal

Active mainly at night.

Social structure

Solitary

Lives and hunts alone, joining others only to breed.

Sighting difficulty

Moderate

Fun facts

  • récordIt is the largest land arthropod in the world, and will climb trees to cut coconuts loose with its powerful claws before dropping them to break on the ground.
  • Its claws exert one of the highest gripping forces measured in the animal kingdom, enough to crack open a coconut.
  • It is so adapted to life on land that it drowns if submerged: it breathes with branchiostegal lungs that it has to keep moist.
  • Its larvae are marine: the females come down to the shore to release them, and the young spend their first weeks at sea, in a borrowed shell, before coming ashore for good.
  • It is the largest land arthropod in the world: up to a metre across the legs and about 4 kg.
  • Its claw is the strongest measured in a land animal: up to some 3,300 newtons in the biggest specimens, a force that far exceeds the bite of most vertebrates and lets it open coconuts.
  • It is a hermit crab that gave up the shell. When young it occupies snail shells like any hermit crab, but as it grows it hardens its own abdomen and does without them for good.
  • It cannot swim: as an adult it breathes with branchiostegal lungs, rudimentary lungs, and it drowns if submerged. The only exception is the female, who goes down to the shore to release her eggs into the sea.
  • Its sense of smell is extraordinary and works in air, not in water: it has remodelled its olfactory organs into a design closer to that of insects, and it detects rotting fruit and carrion from kilometres away.
  • It can live sixty years and takes about five to mature, which makes it very vulnerable to overexploitation; it is listed as Vulnerable.
  • It has been suspected for decades of being the cause of the disappearance of Amelia Earhart's remains on the island of Nikumaroro, though that is only a hypothesis.

Life cycle & biology

Skeleton type
Invertebrate - chitin exoskeleton (crustacean)
Habitat & environment
Coastal forest and scrub on Indo-Pacific islands and atolls
Sexual maturity
5 years

Sources consulted: https://es.wikipedia.org/wiki/Birgus_latro

Related species

Other species in the catalogue with the most in common with Coconut Crab — same habitat, park, country, tags or family.

How to help

The coconut crab is classified as vulnerable. Organizations such as UICN, WWF y Wildlife Conservation Society work specifically on its conservation and that of its habitat; looking into their programs is a good starting point if you want to get involved.

It's documented in 10 real protected areas — part of why protecting these places matters for its conservation.

Keep exploring

Based on what we already know about coconut crab.

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