The killing of an endangered gorilla after a toddler entered its closure at the Cincinnati Zoo this past weekend has prompted outrage among animal rights activists, with one New York group calling for the closure of all zoos.

Kate Riviello president of the animal advocacy group No Kill New York, Inc. started a petition after the 17-year-old silverback gorilla named Harambe was fatally shot on Saturday by zoo officials to save the child.

The endangered animal was killed after a 3-year-old child slipped into its enclosure at the zoo. On cellphone video, it appeared Harambe was initially gentle with the child but began dragging him out of the moat when the crowd's screams seemed to get the gorilla agitated. At that point, zoo officials made the decision to shoot Harambe and resuced the boy unhurt.

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In New York City, the Bronx Zoo is the only zoo that is home to gorillas — in its Congo Gorilla Forest Exhibit — including a male silverback named Ernie. Visitors can watch these animals behind a glass. According to the zoo’s website, any visitors under the age of 17 must be accompanied by a chaperone and visitors are asked to stay on public paths at all times.

The Bronx Zoo did not respond to multiple requests for comments as of press time.

According to the petition — which has garnered over 4,500 signatures — supporters call for the United States Department of Agriculture (USDA) to fire the Cincinnati Zoo’s director, Thane Maynard, and shut down the zoo permanently for allegedly violating the Animal Welfare Act.

“That fault barrier that was penetrated by a [3-year-old] child is the cause of this tragedy,” Riviello said.

A spokeswoman for the USDA said the agency has not opened an investigation, but it will look into "whether there were any Animal Welfare Act noncompliances that contributed.”

Cincinnati police are investigating what happened at the zoo and after reviewing what occurred, according to CNN, authorities will determine if any charges are warranted. It was not clear whether the review will look into the zoo or the young boy’s mother.

Along with calling for the closure of the Cincinnati zoo, the petition also urges for the closing of all zoos and emphasizes the need to give endangered species a sanctuary environment rather than putting them in a place “dangerous to the animals and the public.”

“Tell the USDA to end the cruel and inhumane spectacle that is a ‘zoo,’” wrote Riviello on the petition’s page.

For Dr. Aldemaro Romero, incoming dean of the Weissman School of Art and Science at Baruch College, the first thing to examine is what zoo officials did before deciding to fatally shoot the gorilla.

He added that most zoos tend to have protocols for such situations, such as attempting to distract the animal to take attention away from the child.

“If they did that, and that didn’t work, then I think that the decision they made is a good one because we are talking about a human life here,” Romero said. “You have to make a decision in a split second.”

Romero, a biologist with expertise in animal behavior and conservation biology, said that from watching the video, he could tell that the gorilla was really curious about the young boy and might have thought of him as a small primate.

However,  it is hard to predict how the more than 400-pound gorilla might have acted or what it could have done to the boy if it was hit with a tranqualizer dart to knock it out.

Romero, a father of two, said that one of the big issues in this case is the parent or guardianb's responsibility. The mother, he said, needed to be more attentive because young children tend to think of wild animals as being like people because of what they see in cartoons or movies.

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“[Parents] need to be more responsible,” he said. “ You wonder why she didn’t keep a good eye on her child. Even if you walk on the street, you have to keep an eye on the children.”

When asked about the petition calling for the closing of all zoos, Romero said that this has been an issue going on for decade, and that zoos have become more active in education and preserving endangered species.

“I am not the type of person that is 100 percent against zoos, but I feel sad for the animals,” Romero said. “It is sad to see them living in those conditions.”