Bears are some of the most powerful and adaptable animals on Earth. Found in forests, mountains, and even icy tundras, these mighty mammals thrive in many different habitats. Their thick fur keeps them warm, while their sharp claws help them climb trees and catch food. Some bears, like the grizzly, can run surprisingly fast—up to 35 miles per hour! When winter comes, many bears enter a deep sleep called hibernation to conserve energy.