Before I begin I'm issued with this warning: "The following tour contains graphic violence, torture, drug references and death."

I'm undertaking a time-travelling tour of the Adelaide Zoo's dark history, a dramatised account of true events that took place between 1883 and 2017.

Everything is based in fact; a darkly comedic horror show of events that, save for a number of heritage buildings and a dollop of age-old charm, are in contrast to the well-respected A-class zoo of today.

Before I can pass through the gates, however, a young staff member offers me a vomit bag.

"You might need it," he explains in a solemn tone.

The skeleton of George, the cigarette-smoking orangutan, remains on display. ( ABC Radio Adelaide: Malcolm Sutton )

When bears attack

I enter the zoo and watch a keeper named RH Dorrington in 1902 routinely rattle a lifted grate that separates the brown and black bears' day-time and night-time enclosures.

It prompts the black bear to exit the daytime cage but the brown bear remains inside.

Dorrington enters the cage, where the waiting bear springs up, latches its powerful jaws onto his shoulder and rips off his arm.

He screams until zoo director Alfred Corker Minchin comes running in with other keepers to shoot the bear.

Dorrington survives but the bear finds itself stuffed and placed on display in the Museum of South Australia where it remains today.

This brown bear housed at the SA Museum ripped off a man's arm in 1902. ( ABC Radio Adelaide: Malcolm Sutton )

I go forward in time to 1920, when polar bear keeper Samuel May is cooling one of the arctic beasts with a hose from outside the cage.

May has scratch marks on his face from a previous encounter with a sun bear.

One of the two polar bears slides along the edge of the cage, feigning disinterest, before it lunges towards May, outstretches a 30-centimetre paw, and tears the man's arm off below the elbow.

"It is all up with me. I am gone," May says from his hapless frame on the ground.

Alfred Minchin is once again the first on the scene. He ties off May's arm before he's carted to the Royal Adelaide Hospital but he later dies.

A keeper was fatally attacked by a polar bear at this enclosure, pictured here in the 1930s. ( Supplied: SA Government Photographic Collection (GN13590) )

"[Polar bears] are bad tempered," Minchin explains to a band of reporters seeking answers.

"In fact, they are the most treacherous animals in the gardens and cannot be trusted.

"You know where you are with the lions and tigers, but these fellows will come and take a biscuit out of your hand one day and put their paw out on you the next."

I notice that a fellow tourer watching from alongside me, a young millennial, is looking a little pale in the face.

She's looking at the blood covering the front of the cage where May's hose is still dribbling water.

The polar bear swallows and I notice the severed arm is nowhere in sight.

The zoo was administered by three generations of the Minchin family from 1883 to 1940. ( Photo: Zoos SA )

Social elite and the destitute

We retreat to the 1884 rotunda where I'm surrounded by Adelaide's social elite who promenade about in the latest fashions and eat "delicate sandwiches".

It's Sunday and, after being open to commoners the previous day, the zoo is reserved exclusively for high society and those who helped bankroll the Zoological Society of South Australia's proudest achievement when the gates opened in 1883.

Sorry, this video has expired Zoos SA's Elaine Bensted acknowledges the zoo's dark history and how standards have changed

An elephant suddenly runs past us. We're looking at Frome Road in 1924, when a circus elephant escaped the Exhibition Grounds across the road from the zoo — land that is now occupied by the University of Adelaide.

The director's son, (Alfred) Keith Minchin, is driving along the road and collides with the elephant to send it sprawling to the ground.

Minchin coaxes the elephant back to its feet and calms it down before zookeepers arrive and lead the pachyderm onto the zoo grounds.

He tells journalists the elephant is young and was apparently only "out for mischief".

"It couldn't do much harm. At present it is safely locked up and is amusing itself by battering a bucket."

Huts occupied by homeless and unemployed people lined the banks of the Torrens. ( Supplied: State Library of SA (B5800) )

We return to the zoo during the Depression era between 1929 and 1939, when destitute people lived on the banks of the River Torrens.

Their tents are set up behind the zoo's northern boundary from where some are employed as keepers and given keys to the zoo.

But food is scarce and hungry men are tempted by the many birds and fowl inside.

We watch a man enter the zoo at night, choose a suitably plump bird from the pheasantry, take it back to the Torrens, pluck it, gut it and cook it.

We see several birds, ducks and other winged creatures get their necks broken, generating a crackle sound that causes my new millennial friend to turn even more pale.

Dozens of animals bashed and killed

We walk to 1950 and watch a fox slink into the guinea pig enclosure and proceed to crush the skulls of 38 smooth-coat guinea pigs, leaving just two alive.

We're soon thrust forward to 2002, when an anonymous assailant climbs into the children's zoo enclosure and bludgeons 16 guinea pigs before leaving with some in his pocket.

'Why?' the millennial cries.

Guinea pigs have in the past suffered from both animal and human attacks at the Adelaide Zoo. ( ABC Radio Adelaide: Malcolm Sutton )

We watch two unemployed 18-year-olds climb over the fence on the night of March 24, 1985, armed with a sheath knife and a double-bladed hunting knife.

They make their way to the children's zoo and bash and cut the throats of 64 animals, including guinea pigs, rabbits, flightless rhea chicks, turkeys and chickens, a duck and pigeon, as well as an antelope, a llama, kangaroos, sheep and goats.

We watch the teens move to the alligator enclosure where one of them beats the placid two-metre beast over the head with an iron bar.

He then climbs in and lodges the bar in the croc's eye before he pulls it onto the grass, hits it repeatedly until it's dead, before throwing the animal by its tail outside the enclosure where he disembowels it and cuts off a foot.

One of the teenagers later tells a detective:

"Some of them were running around, and the only way to stop them was to slash at them."

The slaughter in 1985 made headlines around the world. ( Supplied: National Library of Australia [Trove] )

At this stage I hear the sound of splattering fluid. I turn to see the millennial using the vomit bag as instructed, tears streaming from her eyes.

"I can't do this anymore," she says. "It's too much."

But she doesn't turn away and instead watches long enough to see the two boys sentenced by a judge — one to five years in jail, and the other for four years and four months.

We visit 2005 and the morning of June 25 when an 18-year-old tries to climb back over the main gates of the zoo after stealing some ice cream.

The youth unfortunately slips on the pointed gates, impales himself in the groin and severs an artery.

He is found dead on the footpath outside Frome Road by a police patrol just before 7:00am.

The old Adelaide Zoo entrance was made safer after the fatality. ( ABC Radio Adelaide: Malcolm Sutton )

A flight for freedom

"How about some flamingos?" I suggest to my new friend.

We watch one of them arrive at the zoo in 1953, but before having its wings clipped it flies from the zoo and escapes to the Torrens.

Zoo employees chase it along the banks as far as the Gilberton Swimming Club before giving up.

The next day, two men in a boat try to catch the flamingo but it stays well away.

Four weeks later, the bird is spotted 112 kilometres across the Gulf of Saint Vincent at Port Victoria, then at Troubridge Shoals further south on Yorke Peninsula, and then 193 kilometres back over the gulf in the Coorong National Park where it's found shot dead two years later.

The flamingo pond is no longer in operation but once housed one of the oldest of its kind in the world. ( Supplied: State Library of SA (PRG 1605/4/1) )

Still at the low-fenced flamingo enclosure, we see a blind flamingo estimated at more than 75 years old suffering from injuries after receiving a bashing in broad daylight during 2008.

The flamingo, who'd been at the zoo since the 1930s, did recover, but two youths charged over the incident later had their charges dropped because police were unable to obtain enough evidence.

Drunk elephant handlers and dismemberment

At this point, a staff member interrupts our tour with two strong glasses of South Australian gin, the offer of a fresh vomit bag, and a suggestion we check out the elephants.

We wander over to 1956 to see an elephant called Lillian in poor health due to chronic bursitis with haemorrhage.

A decision is made to shoot Lillian after closing, but unlike two previous elephants, one of which stands on display across from the brown bear at the museum, Lillian's carcass is not stuffed or studied.

She is scheduled to be boiled down at Gepps Cross.

The hardest part is getting her there, so three men are given the task of dismembering the elephant into strips five feet long and 16 inches wide, completing the gruesome task under an electric globe after closing.

Lillian offered rides for visitors to the zoo before her grisly end. ( Supplied: State Library of SA (B 12202) )

We hear somebody talking in an angry drunk voice and move to 1957 where an elephant keeper is giving commands to Lillian's replacement, Samorn, who refuses to do what she's told.

We see the same elephant laying on her side in a wallow of mud. The drunk keeper wades through the mud and stands on her side in a bizarre attempt to get her up.

The elephant ignores him, sprays herself with mud, then stands up and sends the keeper falling into the sludge.

We see another drunk elephant keeper banging on the door of the director's on-site house during 1963, trying to quit but having difficulty making sense, and we wonder what it was about elephants and alcohol at the Adelaide Zoo.

Sorry, this video has expired Elaine Bensted talks about the zoo's future

We travel to 1994 and Monarto Zoo, north of Adelaide, where animals are given large ranging habitats to roam and to where Samorn has been moved.

From the view of a silver tour bus, our attention is drawn to four elephant legs sticking up from a dried moat.

Samorn has slipped in the steep moat and is trapped upside down in the warming air.

They use a crane to pull the kicking elephant out, but moments after she's placed gently down with her legs tucked beneath her, she quietly dies.

"I'm not waiting to see what they do with her body," the millennial says, wiping away tears.

Illegal bird trade

We return to the Adelaide Zoo and 1963 as police investigators quiz the new director, William Gasking, about the activities of an import-export agent who operates from Gays Arcade in the city.

Customs documents about live bird consignments are out of whack with those of the zoo, with many extra pairs of parrots and cockatoos being added — a commercial venture for which the agent is eventually convicted.

A black bear enclosure in 1915 at the Adelaide Zoological Gardens which no longer exists. ( Supplied: State Library of SA (B 61609) )

The unlucky Gasking finds himself at the centre of another storm when in October 1963 he backs criticisms made by visiting famous naturalist Joy Adamson, who wrote the book Born Free about her experiences raising a lion cub.

She's angry at the confined quarters of some of the animals, the bear exhibits in particular, and wants the zoo relocated to a larger site in the Adelaide Hills.

Gasking agrees to the concept but later that month receives a letter from the board stating his probationary period of six months will not be made permanent.

Meerkats, squirrel monkeys and opium

The tour continues and we watch a 20-year-old man break into the zoo one night in 2004 and use a net to steal a squirrel monkey. It's found the next day at a home in Edwardstown and the man is arrested.

We watch zookeepers count meerkats in 2006 and confirm an anonymous phone tip-off that a three-month-old critter had been stolen by someone who had jumped the wall and put it in a backpack.

The meerkat is found in a shoebox later that evening in a Hackham West park.

A squirrel monkey like this one at the Adelaide Zoo was stolen but found the next day. ( ABC Radio Adelaide: Malcolm Sutton )

We watch a blue macaw fly out of the zoo during training in 2010 and get set upon by native birds as it tries to settle in parkland trees before keepers eventually entice him back into a cage.

A different blue macaw is then seen taking off during a 2015 training session and go missing. Two days later he's spotted at Prospect in North Adelaide.

When keepers arrive he flies down onto one of their hands and steps happily into his travelling cage.

Still at the aviary, we visit the 1960s, when birds were arriving at the zoo in cages with "sticky" perches.

A keeper frowns at one of the perches and pulls out a hidden plug from its end to reveal a hollow chamber.

The sticky material is the remnants of opium smuggling — the opium having been added overseas then removed at Port Adelaide by persons unknown.

Manu the macaw went missing on Boxing Day in 2015. ( Supplied: Adelaide Zoo )

Skipping past the 2014 case of a quokka that was stolen and recovered the following evening, we watch a Sumatran orangutan called Karta use a stick to short-circuit electric wires and climb onto the brick fence surrounding her enclosure.

It's Mother's Day 2009 and Karta is depressed and looking for her mate, Pusung, who recently died.

The crowd is evacuated and 15 staff members help return Karta to her cage and repair the fence.

We later learn the orangutan has lived a tragic life, having six stillborn infants since 1995.

In January 2017, after giving birth to her seventh stillborn, the grief-stricken animal gives up and passes away.

Karta fell pregnant for the last time in 2016 despite being on contraceptives. ( ABC News: Tony Hill )

It's vastly different now

Rattled and disturbed by our tour, we spend some time walking around the zoo of 2018, looking at the larger enclosures, the co-habitats, the monkey runs where primates climb rectangular columns over the heads of visitors, and the $8 million giant panda bear enclosure.

We take note of the improved security measures, contemporary occupational health and safety requirements, and the remnants of historical buildings that once housed animals in a vastly different era.

The place has changed, that's for sure, despite having a history as darkly interesting as the animals it still houses.

My millennial friend, however, is still looking a little pale.

"Drink?" I ask.

"Sounds good," she says.

This is a representation of true events and not a tour offered by the zoo. It was written with the assistance of long-time zoo volunteer Trevor Klein.