(CNN) Zookeepers shot and killed a rare gorilla on Saturday after a 3-year-old boy slipped into its enclosure at the Cincinnati Zoo, triggering outcry over how the situation was handled. 
 
 If they had to do it again, they would respond the same way, the zoo's director said Monday. 
 
 Cincinnati Zoo Director Thane Maynard said he stands by the decision to kill 17-year-old silverback Harambe to save the child. The boy went under a rail, through wires and over a moat wall to get into the enclosure, according to the zoo. Footage shot by a witness shows Harambe dragging the child through the water as the clamor of the crowd grows louder. 
 
 Zookeepers shot the 450-pound gorilla with a rifle, rather than tranquilizing him. The brief encounter sparked widespread Internet outrage over the decision to shoot Harambe and whether the child's parents were to blame for failing to look after him. 
 
 But those second-guessing the call "don't understand silverback gorillas," Maynard said in a news conference. And, they were not there when it was time to make the crucial decision. 
 
 "That child's life was in danger. People who question that don't understand you can't take a risk with a silverback gorilla -- this is a dangerous animal," he said. "Looking back, we'd make the same decision. The child is safe." 
 
 Tranquilizer darts can take 10-15 minutes to work -- @iamjeffcorwin weighs in on gorilla killed at Cincinnati zoo https://t.co/ctCTN3QRaB — New Day (@NewDay) May 30, 2016 
 
 'We made a difficult call' 
 
 The family was visiting the zoo on Saturday when the boy slipped away and entered the enclosure. Kimberley Ann Perkins O'Connor, who captured part of the incident on her phone, told CNN she overheard the boy joking to his mother about going into the water. Then, suddenly, there he was, being dragged by Harambe. 
 
 The unidentified boy was taken to Children's Hospital and released Saturday evening. The family thanked the zoo in a statement through a public relations firm: 
 
 "We are so thankful to the Lord that our child is safe. He is home and doing just 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. We hope that you will respect our privacy at this time." 
 
 Some suggested the boy's parents should be held criminally responsible for the incident. An online petition seeking "Justice for Harambe" earned more than 100,000 signatures in less than 48 hours. 
 
 "This beautiful gorilla lost his life because the boy's parents did not keep a closer watch on the child," the petition states. 
 
 If you leave your kid in a car you go to jail, if you let your kid fall into a Gorilla Enclosure u should too! #TeamDl — DL Hughley (@RealDLHughley) May 30, 2016 
 
 It seems that some gorillas make better parents than some people. — Ricky Gervais (@rickygervais) May 29, 2016 
 
 Cincinnati Police Lt. Stephen Saunders said he is "not aware of any intention to charge the mother" or "the parents" at this time. 
 
 Maynard refused to point fingers at the child's family. 
 
 "We had a very difficult situation and we made a difficult call at the end. I'm not here to point fingers about fault," he said. 
 
 "We live in the real world, we make real decisions. People and kids can climb over barriers. We work hard to make sure this zoo is safe. People can climb over barriers, that's what happened." 
 
 Well-wishers left flowers by the gorilla statue at the Cincinnati Zoo. 
 
 He also defended the enclosure barriers, saying the zoo has been inspected by both the USDA and the Association of Zoos and Aquariums. He compared the scenario to a locked car that burglars find their way into if they try hard enough. 
 
 He also pointed out this was the first breach of the exhibit in 38 years of existence. 
 
 "The barriers are safe. They exceed any required protocols. The trouble with barriers, whatever the barrier is, some people get past it," he said. "The zoo is not negligent." 
 
 Questions over lethal shot 
 
 Western lowland gorillas are critically endangered in the wild, numbering fewer than 175,000, according to the zoo. An additional 765 gorillas dwell in zoos worldwide. 
 
 At first, it looked like Harambe was trying to help the boy, O'Connor said. The gorilla stood him up and pulled up his pants. However, as the crowd's clamors grew, Harambe tossed the boy into a corner of the moat and stood over him, O'Connor said. As the crowd's cries grew, the video shows Harambe grabbing the boy by the foot, dragged him through the water and out of the moat atop the habitat, O'Connor said. 
 
 JUST WATCHED Gorilla drags 4-year-old in shocking video Replay More Videos ... MUST WATCH Gorilla drags 4-year-old in shocking video 02:51 
 
 Moments later, Harambe was put down, a decision that left many wondering if the zoo was too quick to shoot. 
 
 Ian Redmond, chairman of The Gorilla Organization, said zookeepers had other options. 
 
 "When gorilla or other apes have things they shouldn't have, keepers will negotiate with them, bring food, their favorite treats, pineapple or some kind of fruit that they don't know and negotiate with them," he told CNN. 
 
 "I don't know if that was tried or people thought there was too much danger but it does seem very unfortunate that a lethal shot was required." 
 
 Maynard has said that tranquilizers may not have taken effect in time to save the boy while the dart might have agitated the animal, worsening the situation. Animal expert Jeff Corwin agreed that tranquilizers may have taken too long. 
 
 "... In some situations, depending on what the medication is, it can take upward to 10 to 15 minutes," Corwin said. "It may take multiple shots." 
 
 Many pointed out that a human life was at stake -- especially that of a child -- and that's more important than that of a gorilla. 
 
 @CNN it was the best decision that guaranteed the safety of the kid. You really want to risk a human life for a gorilla ? Stop it. — Danny (@Judge_No_1) May 30, 2016 
 
 Similar incidents, different endings 
 
 Although it was the first incident of its kind at Cincinnati Zoo's Gorilla World exhibit since it opened in 1978, similar cases have occurred with very different outcomes. 
 
 In 1986, a 5-year-old boy named Levan Merritt tumbled into the gorilla enclosure at Jersey Zoo in the United Kingdom. Video filmed by a bystander showed Levan lying on the ground, bleeding from the head and unconscious. 
 
 The footage shows Jambo, a male gorilla, approaching the boy as if to check on him, extending a hand to stroke his back. When Merritt comes to, wailing, Jambo, seemingly startled by the cries, sets off in a different direction. Zookeepers immediately move in to save the boy. 
 
 A decade later, a 3-year-old boy fell nearly 20 feet into the gorilla enclosure at the Brookfield Zoo in Chicago. 
 
 This time, a female gorilla named Binti Jua picked up the unconscious boy, while carrying her own infant on her back, and guarded him from other gorillas. 
 
 In an incredible show of maternal care, Binti took him right to a door so that zookeepers could retrieve him. 
 
 PETA: Captivity not acceptable 
 
 Although gorillas are known to be unpredictable -- not always the gentle giants the world saw in these two cases -- the animal advocacy group People for the Ethical Treatment of Animals said the larger concept of zoos is the root of the problem. 
 
 The animal rights organization said on Twitter the tragic episode was the latest proof that "even under the 'best' circumstances ... captivity is never acceptable for gorillas or other primates." 
 
 Others pointed out that in the end, the odds were stacked against the gorilla. 
 
 Humans imprison gorilla. Human enters gorilla prison. Gorilla gets shot dead for being near human. Humanity is a disease. — daniel (@13forests) May 30, 2016 
 
 Maynard said the zoo plans to reopen the exhibit to the public after a thorough assessment. 
 
 "The exhibit will be completely safe when it reopens." ||||| Buy Photo Cincinnati Zoo and Botanical Garden (Photo: The Enquirer/Cameron Knight)Buy Photo 
 
 Updated Friday, 9 a.m.: Hamilton County Prosecutor Joseph Deters will hold press conference to discuss the Harambe zoo incident Monday at 1 p.m. 
 
 Earlier report: Police have wrapped up their investigation without recommending charges against the mother of a 3-year-old boy who witnesses said fell into the gorilla exhibit at the Cincinnati Zoo, according to a source close to the investigation. 
 
 Hamilton County Prosecutor Joe Deters said in an interview that the Cincinnati Police Department asked his office to look at the investigation, and he agreed. He expects that review will happen Thursday, with a possible determination made by Friday. 
 
 “I will read everything and decide what we’re doing,” Deters said. 
 
 Since Saturday, police had been looking at whether the boy's mother, 32-year-old Michelle Gregg, could be held criminally responsible for what happened. Gregg's name was included in an unredacted police report obtained Wednesday by The Enquirer. 
 
 A 911 call Gregg made Saturday afternoon as 450-pound gorilla Harambe dragged her son through a shallow moat was one of several released Wednesday. 
 
 “He’s dragging my son,” a panicked Gregg told a dispatcher. “I can’t watch this… I can’t watch.” 
 
 The boy suffered minor injuries. The 17-year-old silverback gorilla was shot and killed, zoo officials said, to ensure the boy’s safety. 
 
 During the 50-second call, Gregg told her son repeatedly to remain calm. At one point, she said the male gorilla was “standing over” her son. 
 
 “Be calm,” she shouted to her son. “Be calm. Be calm.” 
 
 Another caller, an unidentified woman, can be heard urging others at the scene to “try and calm down” and "be quiet," to avoid agitating the gorilla. 
 
 “He slammed the baby into the wall,” the woman told a dispatcher. Moments later, she added: “He’s taking the baby into the cave… He’s dragging him from one end to the other. Oh my, God… He’s flinging the child around.” 
 
 The call ended after Cincinnati firefighters arrived. 
 
 The entire incident lasted less than 10 minutes. The first 911 call was made at 3:52 p.m., according to police dispatch records. 
 
 The boy suffered “a concussion and a few scrapes,” Gregg said in a Facebook post. He was treated and released Saturday night from Cincinnati Children's Hospital Medical Center. A statement released Wednesday said he was further examined by his family doctor and "is still doing well." 
 
 The Gregg family's statement said: "We are thankful to the Cincinnati Zoo for their actions taken to protect our child. We are also very appreciative for the expressions of concern and support that have been sent to us. Some have offered money to the family, which we do not want and will not accept. 
 
 "If anyone wishes to make a gift, we recommend a donation to the Cincinnati Zoo in Harambe’s name.” 
 
 Mother works at early childhood education center 
 
 The family is continuing to decline all interview or meeting requests, family spokeswoman Gail Myers said. 
 
 Gregg is employed as site manager of Little Blossoms Academy in College Hill. It is one of four early childhood education centers for children ages 3 to 5 that are operated by Cincinnati Union Bethel, a longstanding Cincinnati social service agency. 
 
 Vehr Communications sent The Enquirer a statement printed on Little Blossoms Academy letterhead. 
 
 “The tragic event that happened at the Cincinnati Zoo over the holiday weekend hit very close to home for Little Blossoms Academy. The child who made his way into the gorilla enclosure is the son of our site manager. She is at home with her son as he recovers from his injuries. 
 
 “The Little Blossoms Academy family is thankful that the child is safe. And, with the rest of the world, we are mourning the loss of the Cincinnati Zoo’s beloved silverback. 
 
 The education center asked that "both the media and the public respect our learning environment and the privacy of our staff and families." 
 
 White House Press Secretary Josh Earnest was asked about the incident Wednesday while on Air Force One. 
 
 He said he’s not aware of any official White House position. He acknowledged that many around the country have own personal opinion about “what can only be described as a tragedy.” 
 
 He said it’s not clear to him there’s any federal role in response to the incident. 
 
 The U.S. Department of Agriculture is conducting an investigation regarding the safety and operation of the zoo. 
 
 Hamilton County commissioners Wednesday said they will ask their appointees to the zoo board to conduct an investigation into the gorilla's death. 
 
 Family spokesperson Gail Myers said there are no plans to purse a lawsuit against the zoo. 
 
 'Hurry, the gorillas are out. My God.' 
 
 The 911 calls do not shed light on why the boy apparently climbed over a 3-foot barrier and then went through several feet of thick bushes before dropping about 15 feet into the moat. 
 
 In one 911 call, a woman who went to the exhibit with her young children started to cry. 
 
 "Hurry," she said. "The gorillas are out. My God." 
 
 Two female gorillas in the exhibit responded to calls of zookeepers to go into an inside area. The male did not. 
 
 The woman told the dispatcher she left the exhibit "to get my children away." 
 
 Enquirer Reporters Dan Horn and Amir Samarghandi contributed. 
 
 Read or Share this story: http://cin.ci/1sLYOm8 ||||| A 3-year-old boy fell into an endangered gorilla's enclosure at the Cincinnati Zoo on May 28, and a witness captured the scene as onlookers shouted for help. The gorilla, a 17-year-old named Harambe, was shot by zoo staff in order for rescuers to reach the boy. (Kimberley O'Connor/ViralHog) 
 
 The young boy wanted a better view of the silverback gorilla living at the Cincinnati Zoo. 
 
 On Saturday morning, the zoo housed 11 western lowland gorillas. By Saturday evening, the population of the zoo’s Gorilla World had been reduced to 10. 
 
 As he struggled to find a good vantage point, the boy, whose name has not been released, tumbled into a moat surrounding the enclosure. A 17-year-old, 400-pound silverback ape named Harambe grabbed the child, dragging him through the concrete moat. To save the boy from further harm, a staff member fatally shot the ape. 
 
 
 
 The gorilla Harambe, in an undated photo. (Cincinnati Zoo & Botanical Garden via Getty Images) 
 
 [‘Shooting an endangered animal is worse than murder’: Grief over gorilla’s death turns to outrage] 
 
 “The gorilla could have killed him if he wanted to,” Derek Spielman, a wildlife pathologist and conservation biologist at the University of Sydney, told The Washington Post in a phone interview. 
 
 The child survived his encounter with the great ape. 
 
 In the aftermath of the event, The Washington Post reported, critics of Harambe’s shooting called for “justice” on social media. (Spielman added that, had this happened in Australia, he believes zoo officials would have attempted to tranquilize the ape first, only turning to lethal weaponry if the darts were ineffective.) 
 
 The Cincinnati Zoo defended its actions. “The Zoo security team’s quick response saved the child’s life,” said the director, Thane Maynard, in a statement on Saturday. “We are all devastated that this tragic accident resulted in the death of a critically-endangered gorilla.” 
 
 Much of the wrath of social media focused on the mother of the child for letting the 4-year-old get away. But the handling of animals in captivity came under fire as well, along with the idea of them being in captivity at all. 
 
 Harambe’s death comes at a time when zoos and circuses are overturning long-standing traditions, in part due to increased scrutiny following “Blackfish,” the 2013 documentary on the killer whale that fatally attacked trainers at SeaWorld. In what commentators have attributed to the so-called “Blackfish” effect, SeaWorld’s stock price plunged, its attendance decreased and the aquarium terminated its breeding program. In early May, elephants performed at a Ringling Bros. and Barnum and Bailey Circus for the last time, ending a legacy of live pachyderm entertainment that had lasted for 145 years. 
 
 Some advocates see events like “Blackfish” as signs that zoos need to rethink captivity. In March 2014, the Scientific American editorial board called for an end to captive elephant and orca whale breeding, citing the animals’ immense sizes, need for large swathes of habitat and their intelligence. 
 
 “We have to change direction, hit the brakes,” Ed Stewart, a founder of the Performing Animals Welfare Society, told the Christian Science Monitor. “We need to change the way we’re doing things.” 
 
 In the aftermath of Harambe’s death, the People for the Ethical Treatment of Animals opined that gorillas have “complex needs,” which zoos “cannot even begin to meet.” 
 
 [‘It could have been very bad’: Gorilla killed after boy falls into Cincinnati zoo exhibit] 
 
 “Yet again,” PETA primatologist Julia Gallucci said in a statement on Sunday, “captivity has taken an animal’s life.” 
 
 How well gorillas fare in zoological captivity is not, perhaps, so clear-cut as the issue of elephants or orcas. There have been have been accidents involving captive gorillas prior to Harambe: In 2005, a Lincoln Park zoo intern was bitten by a gorilla; in 2015, a gorilla rushed the viewing window at an Omaha zoo, finding viral fame in the fractured glass; a month later, a female gorilla died at the Melbourne Zoo after another gorilla attacked her. 
 
 But no gorilla has achieved the notoriety of Tilikum, the orca at the center of “Blackfish” who was involved with the deaths of three trainers. In fact, a captive gorilla named Jambo once protectively stood watch over a boy who had fallen into the ape exhibit at the Jersey Zoo, as the University of Salford’s Robert John Young, an animal behavior expert who studies captivity, pointed out to The Washington Post in an interview. 
 
 “Gorillas are very different from killer whales,” Young told The Post. Recreating a sufficient habitat for orcas — which can cross 60 miles in a day — would be exorbitantly expensive, he said. Gorillas, on the other hand, are in a “much more manageable situation.” Young cites the Philadelphia Zoo, which now allows its gorillas to roam through a 200-foot-long series of walkways and enclosures, as a leader in providing apes with mentally stimulating conditions. “The concept of zoos is changing quite readily.” 
 
 Still, captivity does not treat all gorillas equally. Captive gorillas frequently suffer from cardiac disease, with the National Zoo reporting in 2011 that 30 apes take heart medication. They can be emotionally distressed as well. Laurel Braitman’s book “Animal Madness” recounts the story of Tom, a gorilla sent to a new zoo because he was a genetic match with its inhabitants. There, he shed a third of his body mass after his new ape companions began to assail him. Upon encountering his old human caretakers, according to Braitman, the gorilla began to cry. 
 
 Supporters of keeping gorillas captive note that many belong to species survival programs, in which animals are bred in captivity in the hopes of reintroduction in the wild. Two dozen scimitar-horned oryx were released in Chad in May, for instance, after years of breeding in zoos. Harambe was part of the Gorilla Species Survival Plan (SSP), which was formed in 1988 to preserve a healthy genetic stock of gorillas. 
 
 “This is a huge loss for the Zoo family,” Cincinnati Zoo’s Maynard said, “and the gorilla population worldwide.” 
 
 For gorillas, the situation in the wild can be dire. The International Union for the Conservation of Nature considers the 175,000 or so western lowland gorillas to be critically endangered, facing habitat loss, hunting and the spread of the Ebola virus. 
 
 Unlike the oryx, there are no immediate plans to release captive gorillas. For captive breeding programs to be successful, the wild habitat must first be preserved. “A minority of SSP populations actually participates in reintroduction, but the majority of SSP programs, like the Gorilla SSP, exist solely to create a sustainable captive population,” the Cincinnati Zoo notes on its website. 
 
 It is very possible, Spielman said, that gorillas in the species survival program will have to remain in captivity for at least another hundred years. “Whatever zoos can do,” he said, “is dwarfed by the problems facing biological diversity.” 
 
 Though species survival programs are popularly imagined as an ark, Young argues they are more like car insurance. “You’re hoping that you’ll never need it,” he said. 
 
 “But if we do ruin the planet, at least we’ve got this insurance policy.” ||||| CLOSE How a 3-year-old boy dropped into the Gorilla World exhibit at the Cincinnati Zoo & Botanical Garden. The Enquirer/Mike Nyerges 
 
 Jack Hanna attends Safe Kids Day at Smashbox Studios on April 24, 2016 in Culver City, Calif. (Photo: Jason LaVeris, FilmMagic) 
 
 Celebrity zookeeper Jack Hanna, a Knoxville native and director emeritus of the Columbus Zoo and Aquarium, defended the actions of officials at the Cincinnati Zoo and Botanical Gardens after they shot to death a critically endangered gorilla out of concern for a 4-year-old boy who got into the animal's enclosure Saturday afternoon. 
 
 However, Hanna wasn't ready to defend the mother of the child who slipped away from her supervision. 
 
 Speaking to"CBS This Morning on Monday Hanna said, "I agree 1,000 %" with the Cincinnati Zoo's officials to take out the gorilla before he harmed the unnamed child who had gone under a railing, through wires and over a wall before falling 10-15 feet into a moat in the gorilla's enclosure. 
 
 The 17-year-old, 450-pound western lowland gorilla named Harambe, grabbed the boy and pulled him through the water, keeping the child close as onlookers screamed. The boy was treated at the Cincinnati Children's Hospital Medical Center and later released, and his family says he is doing fine. 
 
 A widely circulated video of the event has left many wondering if lethal force was necessary; some have interpreted the gorilla's actions as more protective than dangerous. 
 
 Hanna has no doubts, however: "They made the correct decision," he told CBS, adding that a shot from a tranquilizer gun might take 5 to 10 minutes to take effect, and it was clear to Hanna that Harambe was already alarmed by the situation and a tranquilizer shot would have aggravated him further. 
 
 "A human being is alive today because of the decision the Cincinnati Zoo made," he said. 
 
 Hanna also defended the safety of zoos in general: "We'd be at the very top of safety (compared to other types of attractions)," however, "We can only do so much (to assure safety) … What do we do? … We can't protect everything all the time." 
 
 Then as a warning to parents, Hanna said, "You always have to watch children." 
 
 About the mother of the boy, he said, "I guess maybe she was doing something else (instead of keeping an eye on her son). I don't know. I wasn't there." 
 
 In an earlier statement, Cincinnati Zoo director Thane Maynard attempted to justify the zoo's actions. "It could have been very bad," he said. 
 
 Many of those following the story online think the killing of Harambe was already "very bad," and a petition, called Justice For Harambe, had already logged more than 210,000 supporters as of dinner time Monday. 
 
 Hanna, 69, is one of the world's most celebrated zookeepers. After growing up in Knoxville, he served as the general curator of the Municipal Zoo in Knoxville in the early 1970s, he was part-owner of Pet Kingdom on Kingston Pike, and he kept a menagerie of wild animals at his Cedar Bluff Road home that he called "Hanna's Ark." 
 
 In July of 1972, a lioness at his home, Daisy, mauled a three-year-old boy who put his hand through a fence. The lioness severed the boy's arm just above the elbow. 
 
 Hanna and his family moved to Florida in the mid-1970s, and he took a job with the Central Florida Zoo in Sanford. He eventually took a position at the Columbus Zoo in 1978. 
 
 Nicknamed "Jungle Jack," the charismatic Hanna has made many media appearances over the decades — notably on talk shows hosted by Johnny Carson and David Letterman — and hosted several of his own syndicated shows, including "Jack Hanna's Into the Wild" and "Jack Hanna's Wild Countdown." 
 
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– Did the gorilla have to die? The Cincinnati Zoo is facing an angry backlash for shooting Harambe, an endangered gorilla, dead after a 4-year-old boy fell in its enclosure Saturday, CNN reports. Protesters who accuse the zoo of using excessive force gathered outside the zoo Sunday and the #JusticeforHarambe movement has started a petition to have the boy's parents investigated for negligence. The zoo, however, says that while it is devastated by the death of the male western lowland gorilla, the boy was in imminent danger and tranquilizers would not have worked quickly enough. A witness says that after the boy fell 15 feet into in the enclosure, the gorilla seemed protective at first, but he became agitated as visitors screaming and started dragging the boy through a moat. A witness tells CNN that to get into the enclosure when his mother was distracted, the boy had to "climb under something, through some bushes and then into the moat." He was released from a hospital on Saturday night and his parents issued a statement thanking the zoo and saying the boy is "doing just fine," the Cincinnati Enquirer reports. "We know that this was a very difficult decision for them, and that they are grieving the loss of their gorilla," they said. The BBC notes that a similar incident in Britain in 1986 had a happier ending. When a 5-year-old boy fell into a gorilla enclosure on the island of Jersey and fractured his skull, a male silverback named Jambo stood guard, stroking the boy and keeping other gorillas away until he was rescued.