Despite its network of enclosures, fences and security measures, Perth Zoo's animals, birds and other creatures still manage to outwit the system and surprise their keepers with their daring and inventive escape attempts.
A log of escape attempts and security breaches over the past year shows many of the zoo's 1248 inhabitants are far from dumb animals, unlike some of the human visitors to the South Perth attraction.
The escapees over the past year include a swimming lemur, a quick-footed quokka and a slippery collection of snakes, including the venomous tiger snake.
Fotsy, a black and white ruffed lemur, is housed with his mates on an island in the middle of the lake, which is designed to be a natural enclosure because lemurs, which are found in the wild in Madagascar, are usually non-swimmers.
Yet in the dead of night in November, Fotsy took a flying leap from a tree into the far side of the lake and paddled his way to the other side, enabling his escape into the public part of the zoo.
As staff arrived to open the zoo the next morning, they found Fotsy in the reception area.
"Fotsy was just over 12 months old when that happened, so was still developing his co-ordination," Deb Read, from Perth Zoo, said.
"We think he jumped from a tree and missed his landing, falling into the water.
"Water in the wild is a natural barrier so we don't have to have fences blocking the view and it makes it much more natural.
"Lemurs can't swim so when he fell in, he managed to paddle across the lake."
Jinda, a red-tailed black cockatoo, flew away from her handler last year and spent a few hours flying around South Perth before deciding that she preferred the familiar surroundings of her aviary.
Jinda's sudden and successful bid for freedom surprised her keepers because the bird was rescued from the wild at the age of 10 weeks and brought to the zoo in poor condition, missing flight feathers from her wings and tail, in March 2011.
A quokka dashed for the door and escaped when its keeper was leaving its enclosure in September but it didn't get away quickly enough and was soon recaptured.
Thieves are believed to have stolen two endangered radiated tortoises, which can grow up to 40cm long, from their enclosure last year.
The tortoises, which are found in decreasing numbers in Madagascar, are sought after in the illegal pet trade because of their beautifully-marked shells and thousands are taken from the wild every year.
The first tortoise disappeared from its enclosure in June last year, with a second going missing in September. Despite a search and review of CCTV footage, the tortoises have not yet been found.
Visitors have also been caught picking up lizards, scratching the shell of a Galapagos tortoise, chasing animals and feeding animals items like chewing gum, chicken bones and jelly lollies.