CHICAGO (CBS) — The arctic blast is an invitation for most to stay indoors, but for some Brookfield Zoo animals, the cold weather means playtime!

(Photo: Jim Schulz/Chicago Zoological Society)

Judy, a 17-year-old Brookfield Zoo bison, doesn’t seem phased by the chilly temperatures the Chicago-area has been experiencing.

(Photo: Jim Schulz/Chicago Zoological Society)

Animal care staff gave the bison, as well as some of the other animals, holiday trees as part of the zoo’s enrichment program. The bison tossed them around and rubbed their horns on them.

(Photo: Jim Schulz/Chicago Zoological Society)

If this isn’t the visual definition of “unbothered,” we don’t know what is.

(Photo: Jim Schulz/Chicago Zoological Society)

Winter is a great time to visit the cold-hardy animals at the zoo, located in the Chicago suburb of Brookfield. In January and February, general admission is free on Sundays, Tuesdays, Thursdays and Saturdays.

(Photo: Jim Schulz/Chicago Zoological Society)

Hudson, an 11-year-old polar bear, also received a repurposed holiday tree, which was adorned with some of his favorite treats.

(Photo: Jim Schulz/Chicago Zoological Society)

Look at that face!

(Photo: Jim Schulz/Chicago Zoological Society)

Whirl, an Amur tiger at Brookfield Zoo, received upside-down holiday trees to go along with the zoo’s enrichment program.

(Photo: Jim Schulz/Chicago Zoological Society)

Whirl’s trees were decorated with bones.

(Photo: Jim Schulz/Chicago Zoological Society)

 

(Photo: Jim Schulz/Chicago Zoological Society)