For more than three decades, a penguin named Mochica charmed visitors and served as an ambassador for his threatened species at the Oregon Zoo.

The flightless bird with an outsize persona — he was described as the "elder statesman" of his colony — personally greeted thousands of guests in his lifetime and was said to prefer the company of humans.

But he was one of the oldest Humboldt penguins on Earth, and his advanced years were accompanied by a decline in health.

Mochica had trouble seeing and walking. He had a mature cataract in one eye and "old-age haze" in the other, according to a statement from the zoo. He also had bilateral arthritis in his hips.

On Saturday, zoo officials decided to euthanize Mochica. He was 31.

"Mochica was the oldest male of his species in any North American zoo or aquarium, maybe the whole world," Travis Koons, who oversees the Oregon Zoo's bird populations, said in the statement.

"His remarkable longevity says a lot about both his zest for life and the quality of care he received over the years," Koons added.

He often preferred people over penguins

Hatched in 1990, Mochica — or Mo, as he was sometimes called — quickly became a people penguin. He thrived on greeting visitors to the zoo and often chose to spend time in his keepers' quarters instead of with the other birds in the penguinarium.

"It was pretty common to walk into the keeper kitchen area and find Mo 'helping' with the food prep or just hanging out with care staff there," Koons said.

As Mochica's condition worsened, zoo staff would slip an arthritis drug into his "sustainable-seafood breakfast" and organize laser-therapy sessions for him.

He survived well past his expected life expectancy

Mochica lived more than a decade past the typical, 20-year life expectancy of Humboldt penguins.

According to Guinness World Records, the oldest penguin in captivity is a female gentoo penguin named Olde who was 41 as of this April .

Now, Koons says he hopes Mochica's legacy will be the continued conservation of Humboldt penguins, of which there are only an estimated 12,000 breeding pairs left. According to the International Union for Conservation, Humboldt penguins are "vulnerable" to extinction.

The species is native to the coastline off Peru and Chile and is threatened by the overfishing of its prey, entanglement in fishing nets and the disruption of its habitat.

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