World Wildlife Fund (WWF) and its partners are taking swift action to protect critically endangered mountain gorillas after three females and one male silverback were discovered shot to death in the Democratic Republic of Congo (DRC).

The most recent census of mountain gorillas in Uganda's Bwindi Impenetrable National Park-one of only two places in the world where the rare gorillas exist-has found that the population has increased by 6 percent since the last census in 2002, according to the Uganda Wildlife Authority, the Wildlife Conservation Society, the Max Planck Institute of Anthropology and other groups that participated in the effort.