The wild and unlikely tale of Rubondo dates to the 1960s, when the Tanzanian National Park service turned over the keys to this densely forested Nantucket-size island in southwestern Lake Victoria to famed German zoologist and Oscar-winning documentary filmmaker Bernhard Grzimek.

Quickly seeing the deserted island’s potential as a protected habitat for endangered wildlife, Mr. Grzimek began to introduce a number of species to the island, including elephants, giraffe and gray parrots. Somewhat surprisingly, all of the newcomers established habitats on the island without upsetting its native wildlife, which includes vervet monkeys, spot-necked otters, crocodiles, hippopotamus and sitatungas (a cousin of the antelope). Read MoreRubondo