The Lujan Zoo is known for having very tame animals, many believe they sedate them but the zoo insists they are calm due to good training and being constantly fed. They raise their animals from when they are born and teach them to have no interest in eating people.
It opened in 1994, and since then, there have been no reports of attacks.
When they first opened, they only had lions, monkeys, two donkeys, two ponies, a llama, a deer and a few peacocks. Their list of animals has since grown immensely, including bears, tigers, and elephants. They have 50 African lions, 20 Bengal tigers, 12 mountain lions and 50 different species of South American monkeys.
Zoo director Jorge Semino said they raise the animals to have constant contact with humans, with the larger cats getting the most attention.
Trainers start working with cubs once they're born and begin lowering violent instincts associated with competing for food. They ensure the babies are able to access their mothers for nursing and that food is distributed equally.
As the animals grow, the trainers use vocal commands to teach them the difference between human hands and the meat they feed them.
They also incorporate dogs into the mix, allowing the big cats to watch the canines interacting kindly and obediently with humans. The trainers believe the dogs act as an example for the wild animals to follow.
"The only way to raise them from when they are babies and educate them with love, affection and respect, and they will return the same," Semino said.
A biologist who works with the zoo, Juan Jose Bianchini, said, "the early learning causes the animals to lose their aggressiveness in a total and irreversible way. They learn to live with other species and lose their aggressive drives which are primarily related to the competition for food."
Many of the animals the zoo has were kept illegally as house pets. They were given to the zoo after being mistreated and undernourished. It is not uncommon for people in Buenos Aires to keep exotic animals as pets, since they are near the Brazilian rain forest. But many of these pet owners get tired of taking care of them, so they give them to the zoos.
While some believe the zoo is an amazing way to get closer to nature, some believe they are exploiting the animals by teaching them to behave in abnormal ways.
The Born Free Foundation is asking authorities to investigate the zoo, saying that "no one wants to see animals forced to behave in ways which are abnormal and degrading to them, and no one wants to see Lujan Zoo (or any zoo) putting its visitors at risk."
Martha Gutierrez, president of the Association for the Defence of the Rights of Animals, said the zoo is sending the wrong message to the public.
"I think it gives a terrible message to the public about the relationship between animals and people. These are wild animals, and are not meant to be under our control," she said.
Semino said he has nothing against the animal rights groups but said the zoo is actually protecting these animals.
"We know that this is not the ideal place for an animal to live, but many zoos, including ours, give protection to animals that were abandoned or born in captivity. An animal born in captivity and who has spent many years in contact with humans can not be released into the wild. They don't know how to survive on their own," he said.
The zoo welcomes people of all ages, and children under age 12 are admitted at a lower cost.