The director of the zoo where a 4-year-old boy fell into a moat that housed a silverback gorilla Saturday said he stands by the decision to kill the 400-pound animal.

“We stand by our decision, and we’d make the same call today,” Thane Maynard, director of the Cincinnati Zoo and Botanical Garden, said at a press conference Monday. He added that people who second-guess the decision “engage in Monday-morning quarterbacking and do not understand primate biology.”

His remarks came as animal rights groups were expressing outrage over the killing of the 17-year-old gorilla.

The silverback gorilla, named Harambe, was “clearly agitated and clearly disoriented” and “acting erratically” Maynard said when the zoo’s dangerous-animal response team was called in to kill the primate.

Video of the incident shows the boy being dragged by Harambe. The boy was being dragged around and his head was hitting the concrete, Maynard said.

 

Witness Kim O'Connor told WLWT-TV she heard the boy say he wanted to get in the water with the gorillas. She said the boy's mother was with several other young children.

"The mother's like, 'No, you're not. No, you're not,'" O'Connor said.

 

O'Connor shared video she and her family recorded of the boy and Harambe. The two appear in a corner of the exhibit while cries of "Somebody call the zoo!" and "Mommy's right here!" could be heard.

After the child fell into the area that houses the primates, the zoo’s gorilla trainers gave the animals a special signal that calls them back inside. Maynard said while the female gorillas responded to the call, Harambe was distracted by the events and did not respond.

Maynard said that officials did not take killing Harambe lightly and that his death was “a big loss” for the gorilla’s trainers and the entire zoo family.

The boy, who has not been identified, fell into the moat where Harambe lived with his gorilla family.

Maynard stressed that the boy was in danger, and said that you cannot take a chance with a silverback. Maynard told a story of seeing Harambe crush a coconut with one hand. In detailing the primate’s massive structure, he said Harambe’s arms were similar to human beings’ legs.

“We lost an incredible, magnificent animal that is important to our program,” Maynard said.

Since the gorilla's death, the hashtag #JusticeForHarambe is trending on Twitter and a petition has been launched calling for "the parents to be held accountable for the lack of supervision and negligence that caused Harambe to lose his life.”

"This beautiful gorilla lost his life because the boy's parents did not keep a closer watch on the child," the change.org petition reads.

The boy's family released a statement Sunday that the boy was home and doing fine.

"We extend our heartfelt thanks for the quick action by the Cincinnati Zoo staff. We know that this was a very difficult decision for them, and that they are grieving the loss of their gorilla," the family said.

Lt. Steve Saunders, a Cincinnati police spokesman, said there are no plans to charge the parents.