The incident sparked debate among biologists and primatologists on whether gorillas and other primates should be held in captivity at all.[11] Primatologist Jane Goodall said that according to the video it seemed Harambe was trying to protect the child.[26] Goodall later issued a longer explanation in an interview with the president of the International Fund for Animal Welfare, concluding that the zoo had no choice but to kill Harambe.[27] She wrote, "It was awful for the child, the parents, Harambe, the zoo, the keepers and the public. But when people come into contact with wild animals, life and death decisions sometimes have to be made."[1] Goodall said that as long as humans and wild animals are kept in close proximity in zoos, there is no way to prevent accidents from happening, but she believed that zoos "with the highest standards of care" could play an important role.[1] Zookeeper Jack Hanna strongly defended the zoo's actions as the "correct decision", noting that a tranquilizer dart might have taken five or ten minutes to take effect and could have aggravated Harambe further.[28] Primatologist Frans de Waal said he saw few options for the zoo: "A gorilla is so immensely strong that even with the best of intentions—and we are not sure that Harambe had those—the child's death was a probable outcome.”[2]