To mark the festive period, presents with food inside were put into some of the enclosures at Brookfield Zoo.
According to officials, the objects help to stimulate the animals, and play an important role in boosting their mental and physical wellbeing.
A variety of food was provided, spanning from vegetables for the tortoise and raw meat and bones for the mammals.
It was based on the specific nutritional requirements of each animal.
Among the animals that received the food filled objects were the African painted dogs, a polar bear, a snow leopard and a lion.
Dating back to 1934, Brookfield zoo is home to more than 3400 animals.
It has a leading reputation in animal care and conservation.
The zoo, which is in the Chicago area, also aims to teach its visitors to look after the natural world.
