Big Bend's New Bear Cubs | America's National Parks | National Geographic

NARRATOR: Nearly 6,000 feet up in the mountains, another mom has a huge challenge. A female black bear has spent the winter in a high mountain cave. She needs to teach her cubs to survive in the park. With little to no food or water for months, the stakes are high.

But they're living in a special place. Big Bend is the only national park with an entire mountain range inside its borders, the Chisos. Named for their previous inhabitants and once home to the Mescalero Apache and the Comanche tribes, the mountains are a sky island oasis. 40 square miles of peaks up to 8,000 feet loom over the hot desert below.

At the height of summer, monsoon storms can dump nearly a year's rainfall in a few months. Right now, the monsoon is a long way off, but the Chisos do something incredible. They catch the rains and store them for year-round use. Water slowly releases from deep in the mountains into precious spring-fed pools, attracting critters of all types and all colors.

The key to survival in a desert is a reliable source of water. And Mom knows exactly where to find it thanks to her mom who taught her about the hidden oases in the Chisos. It's the cubs' first visit to this magical place. Every day is a school day.

Today's lesson is all about water. They've never tasted or seen so much of it. Mom relaxes in the spring, but for the cubs, it's playtime. The fun has to come to an end eventually, but Mom has another lesson for her eager students: how to scratch that itch.

Mom shows how it's done, rubbing off her winter coat and leaving a scent behind, signaling her presence to other bears in the park. Mom made it look easy, but the cubs will need a lot more practice. For the bear family, the Chisos mountains provide water and a cool refuge.

But down below on the desert floor, life in the park has more extreme challenges.