Uncaged! When animals escape their zoos

London Zoo on Friday called the male western lowland gorilla's escape from its enclosure a "minor incident" that posed no danger to the public. He was out of his enclosure for around an hour, ultimately subdued with a tranquilizer dart. Armed police were deployed. The zoo could not say precisely how Kumbuka got loose, but announced that an investigation was underway.

Kumbuka escaped into what the zoo described as a "non-public keeper area." According to a Buzzfeed article citing a zoo source, the ape ("a f------ psycho") had a history of acting up. Eyewitnesses had said he was aggressive and banging the glass prior to the incident. Speaking to the BBC, the zoo's curator of mammals said such behavior was common by males seeking to impress females.

Visitors and staff were locked inside zoo buildings, part of standard emergency procedure, while the case was dealt with. Some reported on their own brief taste of zoo captivity via social media. According to figures from the UK's Association of Leading Visitor Attractions (AVLA), London Zoo attracts around 1.25 million visitors per year, just enough to make the AVLA's top 25 crowd-pullers.

An orangutan in Duisburg fared worse than Kumbuka during his August 2015 breakout. By the time the zoo became aware he was on the loose and laid eyes on him, he was already climbing the outer perimeter fence. Zoo officials said it was then too late to risk a tranquilizer dart, which may not sedate large animals immediately. Female Manggali (pictured here) shared the enclosure with him.

June 2012: a broken branch offers a group of five chimpanzees a new way up and over their fence at Hannover Zoo. During their flight, they overran and injured a five-year-old girl. They were recovered without suffering any violence in the end, tempted back by calls from their keepers.

A snow leopard named Irbis, rather larger and a touch less cute than this cub from the same Wuppertal Zoo enclosure, slipped his cage this September. People were ordered indoors and staff dispatched to deal with the situation. Within around 15 minutes of the breakout, a vet located and tranquilized the endangered mammal. Between 4,000 and 7,000 snow leopards are thought to remain in the wild.

Staff at the Nandankanan Zoo in India had an odd experience with a wild male tiger in 2013. They gave him a home on discovering him lurking around the enclosure's tigress. A month later, though, he seemingly decided love wasn't quite worth captivity - jumping an 18-foot (4.6 meter) wire fence to return to a bachelor's life at large.

A raccoon at the small Tropiquaria conservation house and zoo in Somerset, southwest England, used unusually wet weather to make her escape. She was able to dig her way out with the ground softened. A search was launched, without success, but Missy eventually returned to the male in her pen of her own free will. Perhaps after realizing there were no wild raccoons in the region?

Capuchin monkeys are notoriously smart and sociable - probably why they're becoming a popular pet for the Justin Bieber's of this world. In the wild, they've been observed using rocks as tools, for instance cracking nuts. And in a Brazil zoo in 2012, they did just the same - smashing the locks in their pen and walking out the door.

A penguin at the Tokyo Sea Life Park mysteriously managed to escape his aquarium's walled and fenced enclosure in 2012. Known only as penguin 337, staff launched a frenzied search, fearing that the 1-year-old wouldn't do well in the wild after a life in captivity. They found him two months later in Tokyo Bay seemingly well-fed and healthy, and opted to leave him be.

Back in Germany, a zoo near Hanover lost porcupine Hartmut in 2014 to an open gate, in what might have been an act of sabotage. The prickly fellow showed some real wanderlust, roaming around 5 kilometers from his former home, and putting three of his sharp spines into a fireman trying to round the critter up. His tale ended, alas, under the wheels of a train.

The Opel Zoo in the western German state of Hesse lost a red panda couple for around two days back in 2008, believing that the creatures used bamboo plants to climb to freedom. They were recovered safely, as was Rusty - a young red panda in Washington D.C. who became something of an online celebrity during his brief escape foraging for food. These baby twins were brought to Berlin's zoo in 2011.

Also in 2008, Osnabrück's zoo twice lost track of a male wolf named Roy. His more dramatic second attempt, around a month after the first, involved him jumping his enclosure's borders, tearing away part of the electric fence in the process. He was recovered in the northern German city within a couple of hours though.