A 13-year-old boy who entered an elephant's open-air cage to feed it a mango was crushed to death on Tuesday.

Guillermo Gonzalez got past a rock wall and two metal fences to reach the 4 1/2-ton elephant, named Maia, but the animal reacted violently, stomping the teenager to death before a trainer could intervene.

"Maia understood that its territory had been invaded by a stranger, which is why the elephant trapped Guillermo with the trunk, taking him by the legs and then crushing him with one of its front feet," said Carlos Britos, a veterinarian and director of the zoo.

He described the 35-year-old elephant as docile and obedient with him and other handlers.

The elephant's caretaker, Maximo Ramos, said he has intervened with commands before to protect visitors who got to close. He said he did the same on Tuesday, after he saw the boy had passed the barriers.

"She obeyed and let go of the child, but he was already dead," he said.