The Woodland Park Zoo has bid farewell to Goodwyn, its only male elk.

The 20-year-old was euthanized in July due to a significant decline in his health and quality of life, according to the zoo. The life expectancy for elk in human care is between 18 and 22 years, and 16 years in the wild, the zoo said.

Goodwyn was a Rocky Mountain elk, one of the two subspecies of elk in Washington state. Rocky Mountain elk primarily live on the east side of the Cascade Range, and Roosevelt elk primarily live west of the mountain divide.

Tim Storms, director of animal health at the zoo, said in a news release that the elk had been losing weight and mobility for several months, a common symptom for aging animals. During a complete exam in March, staff members found signs of arthritis in multiple joints, including his knees, and prescribed him medication.

The elk, born at Pueblo Zoo in Colorado, moved to Woodland Park Zoo in 2011. He never had any offspring, but leaves behind three female herdmates: Buttons, Lily and Willow. The zoo said it hopes to get a young male elk in the near future.

“I’ll always remember Goodwyn’s handsome face waiting for me at the fence every day to feed him his favorite ‘elk cookies,'” said zoo animal keeper Karen McRea in a news release.

McRea added that Goodwyn was sweet, good-natured and “a little goofy sometimes.”