Big Hand Crab

Heterozius rotundifrons

The Big Hand Crab, Heterozius rotundifrons, is a small crab species endemic to New Zealand. It is distinguished by its relatively small size, with a carapace width reaching up to 25 millimetres. This species is known for its distinctive defensive behavior; when threatened, it extends all its limbs, including its chelipeds, and remains immobile for several minutes. This unique stance is a notable characteristic that divers can observe during encounters. The Big Hand Crab inhabits coastal waters, typically found at depths shallower than 40 meters, with most occurrences noted at less than 10 meters. Divers may encounter the Big Hand Crab on temperate reefs and rocky reefs around New Zealand. Observing its defensive behavior can be an interesting experience, as the crab remains motionless with its limbs fully extended.