Sheila Siddle's life was changed forever one fateful day in 1983 when a local game ranger brought a battered, malnourished chimpanzee to the door of her cattle ranch in central Zambia and asked her to do whatever possible to save it. As Sheila and her husband nursed it back to health, they treated the young chimp they would name Pal as if he were a human infant – feeding him medicine and bottled milk, sharing their bed with him at night, and carrying him on their backs until he regained the strength to survive on his own.

From these humble beginnings Sheila and David Siddle would go on to launch the Chimfunshi Wildlife Orphanage, an internationally acclaimed animal refuge that has grown to become the home for more than eighty chimps, one disarmingly domesticated hippopotamus named Billy, and a variety of other endangered animals. Currently the largest primate sanctuary in the world, Chimfunshi has been honored by the United Nations Environmental Programme as one of the Global 500 and called by Jane Goodall "the most wonderful place on earth." In My Family Tree is the uplifting story behind one woman's transformation from a grandmother on the brink of retirement to an international animal-rights activist – and the unforgettable chimpanzees she has come to know and love along the way.