Pereira de Souza, a retired bricklayer, has a true friend in penguin Dindim.

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For the past four years, Dindim has returned to the man who saved his life

With a tracking tag, scientists have been able to learn more about Dindim

CNN  — 

Every year, Dindim the Magellanic penguin wobbles into the backyard of a home on Provetá Beach in Ilha Grande, Brazil. Without fail, he comes back in what scientists believe is a sense of loyalty to a man who rescued him when he was at his worst.

You may be familiar with the story of the two friends that captured the hearts of many.

In May 2011, Joao Pereira de Souza, a humble, retired bricklayer, rescued the injured penguin in the state of Rio de Janeiro. The flightless bird was covered in oil and unable to move.

Pereira de Souza took him under his wing and nurtured him back to health, thoroughly cleaning oil residue on the penguin’s body and feeding him for days until he was fit enough to return to the water. Despite his attempt to set him free, the penguin returns every year to his home.

João Paulo Krajewski, a biologist and wildlife presenter at Globo TV, was the first to document the story of Dindim and the man who saved his life.

In an email to CNN, Krajewski said that after all these years, this two-legged survivor returns annually and stays on the island when other penguins of his species are breeding.

“We absolutely don’t know where Dindim goes and this remains a mystery,” he told CNN.

In March, scientists tagged the penguin to find out more about his origins and trajectory. “For the first time, we have definite proof that it is the same penguin returning to Mr. João’s house, since he came back with the tag.”

There have been a lot of misinterpretation about the life of this penguin, including the myth that Dindim is kept as a pet.

“First of all, the penguin is completely free,” Krajewski said in a Facebook post. “It sleeps in Mr. João’s backyard, which is connected to the beach and only partially fenced, since João is concerned about street dogs attacking the penguin.”

And while the idea of a penguin returning to visit every year seems surreal, Krajewski said that most Magellanic penguins are “very loyal to their partner and nesting site. They nest in the same place every year and with the same partner, he said.

“Nothing in nature is 100%, but this would be a rule for penguins, and they recognize each other by their sounds,” he said. “Dindim definitely knows where he is going when he arrives at Ilha Grande, since for four consecutive years he goes, by himself, to the very same spot on Mr. João’s backyard.”

The retiree has become part of Dindim’s family.

Krajewski says his most memorable moment covering their friendship was witnessing Dindim’s bill gently touching Pereira de Souza’s face, as if cleaning him. “This shows how close they are and how comfortable Dindim is around Mr. João,” he said.

CNN’s Amanda Jackson contributed to this report.