Yala National Park in Sri Lanka, one of Asia's most celebrated wildlife preserves, contains one of the world's largest concentrations of leopards.

Scientists hoping to learn more about polar bears face an exhausting challenge: spending hours searching over huge territories and enduring harsh weather.

Primatologist Chloe Cipolletta is trying to befriend a group of western lowland gorillas in order to learn more about how to protect these endangered primates.