The zoo said zookeepers and veterinary staff made the "difficult decision" to put down mountain lion Sierra earlier this week ...

Zoo staff made the difficult choice to euthanize one of the zoo’s two female mountain lions, Sierra, earlier in the week.

The Cheyenne Mountain Zoo is opening its gates to canine companions for a series of special "Dog Days" this spring, offering ...

Colorado Supreme Court struck down a conservation group's lawsuit after they tried to sue using a rule only applicable to ...

From L.A. to San Diego to the Bronx, we rank the 20 largest zoos in the United States that you'll definitely want to see in ...