Red Rock Crab Grapsus adscensionis

There are two similar species of crab called the Red Rock Crab, also called the Sally Lightfoot crab, which were not divided into two species until 1990. This species, Grapsus adscensionis, is native to tropical eastern Atlantic coasts including Ascension Island, West Africa and the Canary Islands.

The related species, Grapsus grapsus, looks similar and is native to western Atlantic coasts of South America and to Pacific coasts of Mexico, Central America and northern South America. They have similar habits and habitats. ("Graspus" is a good name for a crab with such claws.)

This colourful crab (both species) runs around on the tips of 8 of its 10 legs and is an agile climber and jumper on the rocks in inhabits. It's easy to see why it is called the Sally Lightfoot crab.

They live just around the waterline on their rocky coasts and outcrops, often with strong ocean spray. Two of the 10 legs have large front claws.

They eat algae and any other plant material and scavenged animal fragments they can find.

The adult body is some 3 inches (8cm) wide. They are very well camouflaged and seem to be able to adjust their colour to better blend in with their black, red, pink, brown or yellow volcanic rocks.

The juveniles are black with cryptic stripey markings.