Black mambas (Dendroaspis polylepis) are Africa's longest, most famous venomous snakes. Despite their fearsome reputation, these misunderstood snakes are vital players in their ecosystems. They keep rodent populations in check and, in turn, help to protect crops and limit disease spread. The species ranges widely across sub-Saharan Africa, from Senegal to Somalia and south into South Africa. They can adapt to many environments.