The Cheyenne Mountain Zoo closed Thursday after a gas leak was discovered in the early morning, the zoo's website said.
Zoo staff found discovered the gas leak around 5:30 a.m. and shut off heat to the buildings for gas line repairs, the zoo said.
Since heat will not be running in the buildings, the zoo will be closed to the public Thursday but plans to reopen by 9 a.m. Friday.
The zoo staff and animals are safe as alternative heat sources were being used during the shutdown to keep the animals and staff comfortable, the zoo said.
Automatic refunds were given to ticket holders who paid in advance. The refunds will be processed with a few business days. All money will be returned through the original format which ticket holders used to pay, the zoo said.
Those who missed out Thursday can visit the zoo website to purchase new tickets.