Animals at the Brookfield Zoo could be confused this week when they see the staff's uniforms, but no workers inside.
Employees at the Brookfield Zoo have been participating in the #FrozenPantsChallenge by freezing their clothing items and putting them outside the visiting areas of various animals.
Take a look at the animals' reactions below.
Photos: Chicago Zoo Workers Place Frozen Uniforms Outside Animal Spaces
The zoo said workers placed the pants and shirt combination outside animals who typically make an appearance in the cold weather such as bison, polar bears, camels, llamas and sea lions.
Chicago area's Brookfield Zoo closed Jan. 1 and announced the facility will reopen on March 1 "within state restrictions."
With the freezing temperatures across the Chicago area this week, clothing items are able to form different shapes. In order to freeze the clothing, soak the clothes and put them outside. Within about 20 minutes, the items should be solid, according to a Chicago resident.
Tour guide and author Adam Selzer, took things to another level when he decided to combine some frozen fun with dibs, freezing several pairs of pants and leaving some in shoveled parking spots in the city.
He even decided to leave a little how-to for others to join in on the fun.
"Polar vortex fun: pants with nobody inside them!" he wrote. "Soak a pair, put outside. In about 20 minutes you can form them to shape, and in another 20 they’re solid."
Chicagoans have already been mixing things up with items they're leaving in the streets this winter.