The David Sheldrick Trust runs a sanctuary in the park that hand-rears orphaned elephant and rhinoceros calves, and later releases them back into secure sanctuaries. Orphaned and sick animals are brought to the sanctuary from all over Kenya. The sanctuary is located close to the park's main entrance. It was opened in 1963. It was set up by Daphne Sheldrick after the death of her husband David Sheldrick, the anti-poaching warden of Tsavo National Park. Nairobi National Park is sometimes called "Kifaru Ark", which means "Rhinoceros Sanctuary". It is one of Kenya's most successful rhinoceros sanctuaries, and it is one of only a few parks where visitors can be certain of seeing a black rhinoceros in its natural habitat.