Monkeys climb up a wooden box containing an electric heater on Dec. 6 at the Chengdu Zoo in Chengdu, Southwest China’s Sichuan province.

Penguins at the Chengdu Zoo gather around a heater.

A ring-tailed lemur looks at a heat lamp Saturday from its cage at Qingdao Forest Wildlife World in Qingdao, East China’s Shandong province.

A lizard inches closer to a heater in its enclosure on Saturday.

A turtle rests under a heat lamp on Dec. 6 at the Chengdu Zoo.

Ring-tailed lemurs cuddle together next to a heater at the Beijing Zoo on Nov. 30.

A hippo bathes in a warm spa tank on Dec. 6 at the Beijing Zoo.