Mangrove Tree Crab (Aratus Pisonii)

The Mangrove Tree Crab (Aratus pisonii) is a semi-terrestrial crab species found in the mangrove swamps of Dominica, particularly along the Atlantic Ocean and Caribbean-facing coastline. Recognised for its greenish-brown carapace and agile climbing legs, this crab spends much of its life in the prop roots and branches of mangrove trees. Unlike other Land Crabs, it is uniquely adapted to arboreal life, descending to the forest floor and intertidal zone to forage. Its distribution contributes to mangrove ecology and shoreline resilience.

Ecological and Cultural Significance

This crab is a contributor in Dominica’s Biodiversity, feeding primarily on mangrove leaves but also scavenging insects and algae. Its behavior helps recycle nutrients, maintaining the productivity of the island’s marine ecosystems. The species forms part of the diet of fish and birds, linking it to broader food webs signalling more intensified efforts for marine conservation in Dominica. While not commonly harvested, it represents the resilience of wildlife in habitats that protect against coastal erosion and storm surges.

Sightings and Best Viewing Areas

Visitors exploring the Waitukubuli National Trail segments near Castle Bruce or canoeing through Indian River will often spot Mangrove Tree Crabs scurrying among branches. They are most active during daylight, unlike many  other land crabs, making them easy to observe during eco-tours. For travelers interested in Nature Walks thgrough mangrove wetlands at Londonderry and Portsmouth are prime viewing sites where this species thrives.