Special in the CRR
Why Crabs Matter More Than You Think
1 March 2026
Aquatic life in the CRR is abundant thanks to our wetlands. This newsletter will celebrate the one creature children seem to love the most when it comes to water – The Crab!
We will also look at the plants that help to keep our wetlands alive and healthy.
There are approximately 19 different species of freshwater crabs in South Africa. 14 of these 19 are endemic to our Country. They come from the genus Potamonautes.
As a species they do well in a number of different aquatic environments: rivers, streams, ponds, swamp forests, and right here, in the CRR, our wetlands.
They live in tunnels which can be up to 70cm deep usually hidden under logs or rocks for protection and they feed on small organisms and waste. This means they assist in the breaking down of organic matter and the controlling of microorganism populations. They are also responsible for aerating muddy substrates. They are a food source for many different birds, mammals, fish and other invertebrates. Like all the other creatures in our wetlands, they have their own role to play in keeping the all-important balance of this critical ecosystem.
Making sure there will always be a crab population is important and the Mommy crab will release anything up to 850 live, fully formed, tiny little baby crabs into the water. These little creatures will have hatched from the eggs carried in a ‘purse’ formed by their mother’s tail. For the eggs to hatch they need warmer water and will therefore concentrate their breeding efforts during the warmer months.
They are not fans of Winter and although they don’t migrate, they will usually dig themselves into the mud or sand and enter a state of dormancy, slowing down their metabolism.
The single Spine Crab (Potamonautes unispinus) is the most likely crab to be found here. They are relatively adaptable and not considered to be under any particular threat but, like even the most hardy of creatures, urban sprawl is a constant threat to their existence, mostly through loss of habitat. That is why places like the CRR are so very important!
