Arguably one of the fiercest animals in the world, wolverines scare off bears and can single-handedly take down moose and elk, despite being only the size of a medium dog.

Watch the newest member of San Diego Zoo's reindeer herd explore the exhibit with mom.

Meet Xiao Liwu, a giant panda born at the San Diego Zoo.

Watch the bears have a great time after waking up to 15 tons of snow.

It's a great opportunity to see the bears' natural behaviors, such as digging for hidden food.

These fierce animals are extremely well-built for cold weather.

The San Diego Zoo surprised the bears with the snow day, and they sure look like they're having a blast.

Meet Xiao Liwu, a giant panda born at the San Diego Zoo.

Watch as they dig in, roll around, and slide on the 18 tons of snow.

Watch as the younger leopard goes absolutely bonkers playing with a gourd.

See how many tons of snow are needed for the zoo to create a wintry landscape for Xiao Liwu and Bai Yun to play in.

Watch the bears have a great time after waking up to 15 tons of snow.

Watch the newest member of San Diego Zoo's reindeer herd explore the exhibit with mom.

Watch the newest member of San Diego Zoo's reindeer herd explore the exhibit with mom.

Arguably one of the fiercest animals in the world, wolverines scare off bears and can single-handedly take down moose and elk, despite being only the size of a medium dog.

Watch the newest member of San Diego Zoo's reindeer herd explore the exhibit with mom.

These aren't your typical reindeer. Watch as they experience snow for the first time.

Arguably one of the fiercest animals in the world, wolverines scare off bears and can single-handedly take down moose and elk, despite being only the size of a medium dog.

It's a great opportunity to see the bears' natural behaviors, such as digging for hidden food.

Watch the newest member of San Diego Zoo's reindeer herd explore the exhibit with mom.

The San Diego Zoo regularly provides snow for its polar bears as enrichment, but today there's a special competitive twist.

This pair of playful leopards couldn't be any more different. See what happens when they get to experience fresh snow.

It's all part of Reindeer Enrichment day at the San Diego Zoo.

Xiao Liwu is living his best life at the San Diego Zoo. Just in time for his birthday, here's a look back at some of his most memorable moments.