On a recent hike to some of the beautiful waterfalls on Mountainlands Nature Reserve, we came across these two crabs in a small tributary. They drew our attention as we usually see them scurrying away to hide under rocks in the streams, but these two were engaged in what seemed like a tussle. 
When we returned a few hours later things have changed: the tussle resulted in a pre-mating embrace where the male crab has wrapped his claws and legs around the female. Once they have mated the female will carry the eggs under her broad tail from where they will emerge as fully formed, small crabs.
Potamonautes sidneyi (common name: Natal River Crab or Sidney’s River Crab) is a freshwater crab in the Potamonautidae family. It is a widely distributed species that occurs in the eastern part of South Africa. On Mountainlands they are an important prey item for river otters and water mongooses.
