Como Park Zoo announced on Monday the death of its 25-year-old male Plains zebra, Ulysses.

The St. Paul zoo says Ulysses died overnight Sunday into Monday. They do not yet know the cause of his death, but a necropsy will be conducted to learn more. The life span of a Plains zebra is up to 25 years, according to the zoo's website.

"If you've been to Como in the last 20 years, you've probably met Ulysses," Como Zoo said in a social media post. "He roamed between both African Hoofstock habitats and made friends with whatever species he was living with at the time, whether it was giraffe, tortoise, or ostrich. Zookeepers often joked that he was the 'surrogate weird uncle' to many giraffe calves over the years."

Ulysses was born on April 13, 2000, at the Cleveland Metroparks Zoo before being moved to the Como Zoo in January 2002.

Zoo officials say Ulysses weighed around 550 pounds and sired 10 offspring. He had been the second-oldest male Plains zebra in the Association of Zoos and Aquariums population.

Last month, Como Zoo welcomed two new Hartmann's Mountain zebras, 7-year-old Khomas and his 1-year-old son Keanu, to the zebra yard. Introductions between them and Ulysses went well, the zoo said shortly after the pair arrived.