The decision to shoot and kill a 17-year-old silverback gorilla after a three-year-old boy fell into its enclosure has been intensely scrutinized and questioned as to whether it was the right thing to do.

According to Greg Tarry, associate director of Canada’s Accredited Zoos and Aquariums, and Jack Hanna, director emeritus of the Columbus Zoo and Aquarium, the Cincinnati Zoo made the right call.

The four-year-old boy fell three metres into the moat surrounding the gorilla enclosure. Harambe immediately approached the boy and at one point dragged him through the shallow water.

Zoo staff were able to get the two females who shared the enclosure with Harambe to leave with a whistled code, but Harambe wouldn’t budge. According to Hanna, this could have confused Harambe further, seeing his family leave the enclosure.

“They had spent almost 10 minutes trying to separate the gorilla from the child and it was obvious that the gorilla was not going to let go of the child,” Tarry told CTV.

He also said that there was likely a very small opportunity to shoot the gorilla without harming the child. In the absence of any alternative, he said, zoo officials did what they had to.

Thane Maynard, Cincinnati Zoo director, applauded his staff for making a difficult, but in his opinion right, decision. He acknowledged the fact that lowland gorillas are extremely endangered animals, but said that this story had the proper ending.

Many critics have suggested using a tranquilizer instead of a bullet to subdue the gorilla. Zoo officials said that a tranquilizer could not only anger the gorilla, but would be too slow to subdue the nearly 200 kg primate, taking approximately five to 10 minutes to work.

Tarry agreed, saying that people often have a misconstrued view of tranquilizers from movies and TV shows and that tranquilizing was not a realistic option.

“Tranquilizer guns are not exactly that accurate and so, if you were to fire a dart with enough immobilizing agent to knock down a 400 pound gorilla and you knock down the child, you would kill the child,” he said.

Hanna seconded these thoughts, saying that although questions about tranquilizers are a valid, the child would not have survived the incident had zoo staff used one.

“Let’s say the tranquilizer hit him in the bottom or wherever it hit him, you think he’s going to sit there? He’s going to jerk the child. The child could be in pieces in a matter of seconds,” said Hanna.

Comparisons have also been drawn between this incident and two others involving children falling into gorilla enclosures. Binti Jua, a female gorilla at the Brookfield Zoo in Illinois, and Jambo, a male gorilla at the Jersey Zoo on the Channel Islands, both protected the children who fell into their enclosures and neither the gorillas nor the children were harmed.

However, according to both Tarry and Hanna, the situations are completely different. The atmosphere around Harambe was very loud, with both the child and onlookers screaming while the other two situations have involved quiet children, one unconscious. Tarry says that behaviour likely confused Harambe who was already in a distressing situation.

Hanna added that while zoo keepers were able to enter Binti Jua’s enclosure and remove the child from her arms, they were only able to do so because she was female and she was raised by humans at the Columbus Zoo, something that is no longer done.

“If you think about the role of a silverback gorilla, their role is to protect their females and to protect their territory,” Tarry said. “When this totally unknown drops right into the middle of their territory, I’m sure that he didn’t know what to do.”

The dead giveaway for Hanna, in this situation, was when Harambe grabbed the boy by the arm. To him, this showed the gorilla’s anger and confusion at the situation and was what ultimately left the zoo staff without another choice.

“The point is, it’s human life and animal – correct? The gorilla was going to do damage,” Hanna said.

Gorillas have been known as gentle giants, especially in comparison to other animals such as lions and tigers, but at the strength and speed that they have, dangerous has to be considered.

“I think that the idea that a gorilla would intentionally to try to kill somebody is probably not valid,” Tarry said, “but an animal that size with that amount of strength … they could kill them whether they meant to or not.”

The Cincinnati Zoo’s gorilla enclosure remains closed indefinitely.