When a snake bit Lolo, one of 62 chimpanzees Humane Society International cares for in Liberia, sanctuary director and veterinarian Richard Ssuna gave him antibiotics and pain medicine hidden in rice balls. Lolo lives on one of six mangrove islands where animals were retired from research starting...

In a quiet corner of Black Beauty Ranch, on a stone plinth beneath a maple tree, there’s an oval etching of a man and a burro. The man is Cleveland Amory, author and founder of the Fund for Animals, and the burro is Friendly, one of the first animals to call the sanctuary home. The two met in 1980...