A pregnant female chimpanzee at a zoo in Switzerland has adopted her sick sister’s baby, caring for the vulnerable infant under the watchful eyes of zookeepers, even after the birth of her own baby. On Oct. 13, Basel Zoo, a nonprofit in the city of Basel, Switzerland, shared heartwarming footage of the adoptive mom with two young charges on Facebook. “Chimpanzee female, Kitoko, is currently fostering two young animals at the same time,” the zoo explained in a separate post. “She adopted the son of her sister, Fifi, who couldn’t take care of her newborn due to health reasons.” Touching photos show Kitoko with her baby boy, Sabaki, and baby niece, Sangala, hugging, playing, and nursing together. A healthy baby, Sangala was born on June 26 to 28-year-old Fifi. All seemed fine until Fifi deferred to other members of the chimp group “unusually early,” the zoo explained in a news release. In …