There are not a huge number of ways to become famous as a polar bear. Gus somehow managed to do it by behaving like a perfectly ordinary New Yorker: he was neurotic. He became the Neurotic Polar Bear.

To be sure, it was his own particular neurosis. Back in the mid-1990s, he began swimming obsessively for hours through his watery habitat in the Central Park Zoo, as if prepping for the Polar Bear Olympics, something he had never done back in his hometown, Toledo, Ohio. The world took notice. Expensive therapy was ordered. Improvement occurred. A furry white celebrity was born.

Long the popular face of the zoo, even as his lap swimming became less obsessive, Gus began exhibiting a loss of appetite in recent days. He was having trouble chewing. Zoo veterinarians hoped it might be just a bad toothache. But when they examined him on Tuesday afternoon, they found a large inoperable tumor in his thyroid region and decided to euthanize him.

Gus was 27. (The Association of Zoos and Aquariums puts the median life expectancy for a male polar bear living in a zoo at 20.7 years.) He came to New York in 1988, three years after being born at the zoo in Toledo. His parents, Nanook and Snowball, died in 1996. Nanook was from the Bronx and was sent to Toledo for breeding, with the expectation that a cub would go to New York.