In the past month, there’s been a surge of zoo-related violence and injury in the news. A flamingo was stoned and kicked to death in Prague. A white rhino in a Paris zoo was killed, its horn sawed off. El Salvador’s prized hippopotamus, “Gustavito,” died of wounds after he was violently attacked, and a crocodile at a Tunis zoo died after it was stoned by visitors.

The incidents have again raised questions for animal rights activists and zoos alike about what’s being done to keep zoo animals safe.

“I think it’s a reflection that there are some human beings who still see animals as things,” Brittany Peet, director of captive animal law enforcement for PETA, told the NewsHour. Peet argued these international events, as well as the death of Harambe the gorilla at the Cincinnati Zoo in May 2016, highlight that “we simply can’t adequately provide for animals in captivity.”

Certainly, there are many that disagree. Many people argue zoos are necessary for education and exposure to animals they otherwise would not see. But here at NewsHour, the recent incidents made us wonder: How are U.S. zoos keeping animals safe?

The Association of Zoos & Aquariums requires a comprehensive, eight-month accreditation process for its member zoological facilities — considered the gold standard of zoo safety and welfare. The association includes 215 accredited zoos, aquariums, nature and science centers that care for a combined 750,000 animals, and spend $160 million on conservation annually. AZA-accredited zoos undergo four drills every year to maintain safety protocols and must report any incidents or injuries to the Accreditation Commission.

Animal rights group Born Free, which maintains a database of reported animal incidences at both AZA-accredited and non-accredited zoos and animal facilities, reported 146 “animal incidents” in the past year at AZA-accredited facilities in the U.S. Most involved minor injuries or euthanizing sick or aging animals. Another 118 animal deaths occurred at AZA-accredited locations, with 10 happening due to human error, including the gorilla Harambe’s death at the Cincinnati Zoo.

Ron Kagan, the director and chief executive officer of the Detroit Zoological Society, said in an email to the NewsHour that “none of us talk about specifics of our security protocols,” but “clearly everyone is revisiting the issue,” as they did after Harambe’s death.

An inspection after that incident revealed a barrier separating the gorilla exhibit was not up to standard. In response, the zoo replaced the barrier and added three surveillance cameras, a local Cincinnati station reported. After the poaching incident in France, local police have helped step up security. Zoos have also added features like moats and additional meshing to put more space between the animals and visitors.

SeaWorld, though not a zoo, terminated its breeding program and orca shows after widespread scrutiny, which Roberts said represents a step forward for animals in captivity.

“We’re constantly looking at making our institutions as safe for people and as good for animals as they can possibly be,” Dennis Kelly, director of the Smithsonian’s National Zoo and Conservation Biology Institute, told the Diane Rehm Show last year.

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But Born Free USA CEO Adam Roberts, who has been an animal advocate for 26 years, told the NewsHour that “when we keep these wild, dangerous animals in city centers around the world, it’s not surprising that there’s violent conflict. And sometimes that affects people, sometimes it’s the animals.”

Born Free hopes to rid the world of illegal animal facilities and trade. While Born Free eventually wants to shut down zoos entirely, the AZA’s long-term goal is instead to have all zoos accredited.

Animal television host Jack Hanna, the director emeritus of the AZA-accredited Columbus Zoo, believes “zoos and aquariums are the ark” for animal conservation. For Hanna, zoos are a place to save wild animals from poaching, increased human population and loss of habitat. “What is the wild now?” he asked. Hanna believes the terms ‘wild’ and ‘captivity’ should change to ‘natural habitat’ and ‘human care’ in zoos.

“Today, we’ve evolved from menageries to centers of conservation,” Hanna said, nothing he supports the new forms of animal breeding, conservation and education at modern zoos.

Zoos have always existed to some degree. Roberts says facilities should act as a sanctuary to animals instead of outlets for breeding or purchasing exotic animals.

“Zoos are oftentimes the only connection that people will ever have to wildlife,” Vernon said. “If they didn’t exist, people would not have the opportunity to see and elephant or a lion or a tiger up close, let alone a whale shark or sea otter, or even killer whales.”

Roberts says as sanctuaries, zoos can educate visitors on animal violence and illegal trading to help prevent these situations from occurring in the future.

“If you’re going to try and keep these animals in captivity, you have to really meet a high bar, a high threshold of animal care and human safety before anyone can come into those facilities,” Roberts said.