Gus, the Central Park Zoo’s beloved polar bear who earned the nickname “bipolar bear” for exhibiting some neurotic quirks, was euthanized Wednesday after a tumor was judged to be inoperable. Gus was 27 years old and weighed 700 pounds. He came to New York in 1988 after being born in Toledo, Ohio. An icon to a generation of New Yorkers, he was visited by 20 million tourists in his 23 years at the zoo. He had battled health problems, though, and during an operation surgeons found a tumor near his thyroid that had caused him to suffer from loss of appetite and difficulty swallowing food. Farewell, Gus! Here are just a few of the ways we’ll miss you. Julie Larsen Maher/Wildlife Conservation Society, via AP Gus's biggest claim to fame was his swimming prowess—at one point, the bear, who was born in captivity, paddled around his enclosure in figure-eight patterns for up to 12 hours a day. Every day. The peculiar habit enchanted patrons, but it bothered zookeepers, who hired an animal behaviorist to help figure out how to give the guy a break from his neurotic routine. Eventually, with some new toys and some more challenging games at meal time, Gus stopped swimming quite as much, but he never gave up the laps for good. Michael Albans/NY Daily News, via Getty Polar bears like Gus are classified as a vulnerable species, and their Arctic habitat is increasingly threatened by climate change and hunting. There are only about 25,000 polar bears in the world, according to the Wolrd Conservation Union. Diane Bondareff/AP Gus, who died at 27, never had any offspring, but he enjoyed the company of two female companions during his time at the Central Park Zoo. Ida, his most recent, died from liver disease at age 25. This picture shows the two of them in 2006. Lily, his first companion, died in 2004. Of course, Gus also wooed zoo patrons every day. Michael Albans/NY Daily News, via Getty Now that Gus is sadly gone, 22-year-old Tundra, who lives at the Bronx Zoo, is the only cuddly white bear in New York City. According to The New York Times, Central Park may find another polar bear to live in Gus’s enclosure—or they might put a seal there instead. Frank Franklin II/AP “He was the iconic image for Central Park,” according to Jim Breheny, who runs the city’s zoos. Indeed, Gus was a big driver of ticket sales during his decades in the park. His strange swimming habits even inspired a popular book, What's Wrong With Gus? The True Story of a Big City Bear.