Natal Rock Crab

Grapsus tenuicrustatus

The Natal Rock Crab occurs along the tropical coastlines of the Indian and Pacific Oceans, stretching from South Africa to Polynesia and Hawaii.

Adults Natal Rock Crabs are carnivorous and live in the intertidal zone on rocky shores where they scavenge for food, living or dead. While they may occur in large numbers on the rocks, these crabs are actually quite solitary and any “social” interaction with others of their kind revolves only around mating. They’re very fast and agile and not even heavy pounding by the surf will easily dislodge them from the rocks.

Natal Rock Crabs breed throughout the year and males in their breeding prime are distinguished by their bright colours. Females carry their eggs in a “purse” beneath their bodies and drop their larvae, numbering up to 100, into calm water when they hatch, about 3 weeks after being fertilised. The larvae are free-swimming in shallow offshore waters and feed on phytoplankton, moving back to the rocks when they metamorphose into miniature adult form. Adults have a carapace up to 8cm wide. They grow continuously throughout their lives, molting as they go, and can regenerate lost limbs.

19 thoughts on “Natal Rock Crab

    1. de Wets Wild Post author

      Thank you, John, and quite well adapted indeed – seeing them manoeuvre through the rocks and in and under the waves you’d have difficulty not to understand how well they fit in their niche.

      Liked by 1 person

      Reply
    1. de Wets Wild Post author

      Thank you, Anne – I find that our invertebrate fauna are poorly represented in reference works (that would suit my budget, perhaps) so I feel I know far too little about most of them.

      Liked by 1 person

      Reply

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