Bryan McAllister’s personal reference notebook
August 1, 2026Short & citedBlog
Civic Viewpoint.
A quiet encyclopedia with a personal desk
Kept by Bryan McAllister — short guides, clear facts, and the Canadian angle when it matters.
Field Notes • Crustacean

Coconut crab

The coconut crab (*Birgus latro*) is a large terrestrial hermit crab found on tropical islands in the Indian and Pacific oceans.

Updated August 1, 20261 min readCited sources

The coconut crab is the largest living terrestrial arthropod, roaming tropical islands across the Indian and Pacific oceans. It's a giant hermit crab known for its powerful claws and ability to crack open coconuts.

What is a coconut crab?

The coconut crab (*Birgus latro*) is a terrestrial hermit crab in the family Coenobitidae. Adults can reach a leg span of about one metre and weigh up to 4.1 kilograms. Unlike juvenile hermit crabs, adults do not rely on shells for protection.

Behaviour and diet

Coconut crabs are nocturnal and omnivorous, feeding on fallen fruit, seeds, carrion, and other organic matter. They are famous for climbing trees to reach coconuts, which they crack open with their strong claws. They also scavenge near campsites, earning the nickname 'robber crab'.

Conservation status

The species is listed as Vulnerable by the IUCN. Populations face threats from hunting for food and habitat loss. The coconut crab has disappeared from parts of its former range in the Indo-Pacific, making conservation efforts important.

In short

  • Largest living terrestrial arthropod.
  • Nocturnal and omnivorous; eats coconuts and carrion.
  • Listed as Vulnerable due to hunting and habitat pressures.
  • Found on tropical islands across the Indian and Pacific oceans.
Canadian angle

Coconut crabs are not native to Canada, but they are of interest to Canadian readers through zoos, aquariums, and conservation coverage of Indo-Pacific wildlife.

Quick questions

What is a coconut crab?
A coconut crab is a large terrestrial hermit crab, scientifically named *Birgus latro*.
How big can a coconut crab get?
Adults can reach a leg span of about one metre and weigh up to about 4.1 kilograms.
Why is it called a robber crab?
It is called a robber crab because it can steal food and objects, especially around campsites and settlements.

Sources

  1. Wikipedia — https://en.wikipedia.org/wiki/Coconut_crab
    Supports: Scientific name, common names, terrestrial hermit crab classification, and size.
  2. Encyclopaedia Britannica — https://www.britannica.com/animal/robber-crab
    Supports: Common name, taxonomy, and general description as a large nocturnal land crab.
  3. World Animal Rescue Network — https://worldanimalrescuenetwork.org/wildlife-guides/coconut-crab/
    Supports: Distribution, size, and IUCN Vulnerable status.
  4. Natural History Museum — https://www.nhm.ac.uk/discover/coconut-crabs-bird-eating-giants-on-tropical-islands.html
    Supports: Largest land-dwelling arthropod status and Indo-Pacific distribution.
  5. San Francisco Zoo & Gardens — https://www.sfzoo.org/coconut-crab/
    Supports: Diet, nocturnal behaviour, tree-climbing, shell use in juveniles, and conservation pressures.
  6. Australian Geographic — https://www.australiangeographic.com.au/fact-file/fact-file-coconut-crab-birgus-latro/
    Supports: Size, lifespan, diet, and presence in the Indo-Pacific.