From wiki:
Birgus latro, is the largest land-living arthropod in the world, and is probably at the upper limit of how big terrestrial animals with exoskeletons can become in today's atmosphere.
Cannot swim, drowns in water.
Has lungs.
Has gills, for breathing in water. Does not use the gills, just an evolutionary throwback (In your face, creationists!)
As most crabs live in the water, they have specialized organs called aesthetascs on their antennae to determine both the concentration and the direction of a smell. However, as coconut crabs live on the land, the aesthetascs on their antennae differ significantly from those of other crabs and look more like the smelling organs of insects, called sensilia. While insects and the coconut crab originate from different evolutionary paths, the same need to detect smells in the air led to the development of remarkably similar organs, making it an example of convergent evolution.
The coconut crab climbs trees to eat coconuts or fruit.
The coconut crab, especially if it is not yet fully grown, is also sold as a pet, for example, in Tokyo.The cage must be strong enough that the animal cannot use its powerful claws to escape. Should a coconut crab pinch a person, it will not only cause pain, but is unlikely to release its grip.
While the coconut crab itself is not innately poisonous, it may become so depending on its diet, and cases of coconut crab poisoning have occurred.
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