Associated Press - November 20, 2009 1:25 AM ET

PORTLAND, Ore. (AP) - Oregon Zoo officials say Pete, an 18-year-old black bear who loved to lounge in a tractor tire, has been euthanized because of his age and debilitating arthritis.

Pete was named for Petersburg, Alaska, where he had been found orphaned as a cub in January of 1991. The bear and his tractor tire - which did double duty as a toy and security blanket - came to the Oregon Zoo in March 2007, with the opening of Black Bear Ridge.

He spent his first 16 years at Wildlife Images, near Grants Pass.

Keeper Virginia Grimley called Pete a remarkable bear, adding, "He was laid-back and brought a lot of happiness to the keepers who worked with him - and he really loved that tire."

Zoo spokesman Bill LaMarche says all 3 of the zoo's geriatric black bears have died this past year. The zoo is currently seeking to acquire three black bears from an accredited zoo in Utah. Black bears are the smallest of the three bear species native to North America, which include the grizzly and the polar bear.

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