The Selous Game Reserve in the south of Tanzania is home to 60 percent of Tanzania's elephants. Among the largest undisturbed, protected areas in Africa, it has also become one of Africa’s elephant “killing fields.” Those on the front lines studying elephant behavior witness the alarming effect poaching has had on the elephants that survive. This clip from the National Geographic film Battle for the Elephants documents the disturbing changes in elephant behavior, including dramatic displays of fear and increased agitation, stress, and aggression in the presence of humans.

Scientists who study elephant behavior agree that survivors of poaching are stressed. Their fears can disrupt the elephants’ complex matriarchal social structure, reduce their success in breeding, and increase their antagonism toward humans. Elephants mourn their deceased companions, demonstrating rituals that include touching the remains and carrying the deceased elephant’s bones or tusks with them.