One of college football’s biggest — and to some, greatest — mascots is hanging up her harness. She just loves the job too much to keep going.

Ralphie V, the 1,200-pound buffalo at the University of Colorado, is retiring after 12 seasons of leading the Buffaloes’ football team onto Folsom Field and performing other celebratory bovine tasks.

Whereas past Ralphies have slowed down with age, Ralphie V has gotten faster and stronger, which worried some.

“She has been so excited to run that she was actually running too fast, which created safety concerns for her and her handlers,” the university said in a news release.

She will spend the rest of her days — buffalo can live for more than 20 years, and Ralphie V is 13 — on a secret ranch near the university campus in Boulder. Her handlers keep her location confidential so fans don’t flock to the site — or, worse, so opposing fans don’t try to harass or kidnap her.

Ralphie V began her mascot tenure as a yearling in 2007. She weighed 450 pounds, less than half of her current weight. Immediately, one thing was clear: She loved to run.

“Her personality is very fun and energetic,” said John Graves, the university’s Ralphie program manager and her trainer. “She really, really loves to run on game day.”

That’s not always the case with buffalo, Graves said. They’re huge, and running expends a lot of energy. And in the wild or in large pastures in captivity, they don’t have much to run from. A running buffalo, he said, is a buffalo at play.

Over the years, Ralphie V has gotten more and more hyped up about leading the Buffaloes onto the field at the beginning of the game and out of the locker room to start the second half.

She picks up on the cues from her handlers and will hunch down and surge out of her pen as the public-address announcer bellows, “Here comes Ralphie!” followed by, “and the Colorado Golden Buffaloes!”

She almost knows, Graves said, that she’s the main attraction, not the football team.

“She knows that she’s a queen, and she knows that everyone in the stadium is looking down on her and filming her,” he said.

Running with her are 16 “Ralphie Handlers,” students who volunteer to care for the mascot. Five of them sprint around the field with her, holding guide ropes to help her steer and slow down. The rest spread out across the field and keep her path clear of debris — and humans. It’s a physical job; handlers train and practice five days a week, and they earn a varsity letter from the athletic department.

But Ralphie V started giving them trouble midway through this season.

Graves had to keep her from running at the Buffaloes’ past two home games, against Southern California and Stanford, because she was too riled up and not responding properly to handlers. That’s when he and school officials knew that, after 12 seasons, it was time to find a new mascot. She will attend her final football game Nov. 23 against Washington but only in her pen. She will not run on the field.

Graves has already started considering Ralphie VI. He’s looking for a female buffalo roughly a year old. (Ralphies are always female; male buffaloes grow to weigh up to 2,000 pounds and can exhibit more aggressive behavior.) He takes special care to evaluate the animals’ joints and how it behaves around people.

He’s not necessarily looking for a slower Ralphie, he said, but it wouldn’t hurt. The five handlers on the guide ropes can maintain control without too much trouble. He’s mainly looking for consistency. Ralphie IV lumbered around the field in more of a jog, he said, and later into more of a parade. Ralphie V liked to sprint her route.

“We look for the one who wants to do the job, the one that’s comfortable with humans,” Graves said. “Whether they are fast, slow or in between, that’s for them to tell us.”

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