(Portland, OR) -- One of the Oregon Zoo's oldest residents has died. A chimpanzee named Leah was 47-years-old and died in her sleep. Leah was born at the zoo in 1974 and got the attention of renowned primatologist Jane Goodall. While Leah was old for a chimpanzee, she is survived by her sister Delilah who turns 49 next month. The zoo's male chimp Jackson is 50 and troop leader Chloe is 53. Wild chimpanzees live to around 33 years of age. Zookeepers say Leah was known for her sweet demeanor.