African forest elephants have an extremely slow birth rate, putting them under greater pressure from poaching, research suggests. The forest elephant population has crashed by more than 60% since 2002, with the species now inhabiting less than a quarter of its potential range of the Congo basin in Africa. The research found that not only does it take more than 20 years for female forest elephants to begin reproducing, but they also give birth only once every five to six years.