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.
DeWetsWild 
Very interesting Dries. I realise that I have not ever given the lifecycle of crabs much thought!
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I only know the bare minimum about it, Carol, and most of what I know dates back to high school biology in the 1990’s!
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Still standing you in good stead!
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Interesting post, as usual. it seems they are well adapted to their environment.
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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.
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Re-generating a limb is quite an achievement.
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Wouldn’t it be wonderful if we could do the same with pancreases…
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It would be wonderful, Dries.
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What an interesting deviation from your usual interesting fare – I haven’t seen a crab in far too long!
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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.
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I agree with Lois. Do people consume these crabs?
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Not much meat on these, Hien, and they’d be very. very difficult to catch, so I don’t think becoming a seafood dish to humans are much of a risk.
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I do not know much of crabs even when I’ve seen them in many places. Good post, D. 🙂
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I think it is fascinating to learn about the invertebrates, H.J. I’m really enjoying it every chance I get.
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They really look like some sort of prehistoric creature, don’t they? But so interesting. Hope your weekend’s been good so far.
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We’re having a lovely weekend, thanks Janet, and I hope you can say the same?
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I can, although it’s been quite hot–106F. But next week we’re looking at some 111 days, so I’ll enjoy these! 🙂
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Kind of a pretty crab, isn’t it?
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I agree, Lois!
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