Watch the full episode of the PBS Nature film which examines koala communication, vocalization, and social structure.

Watch the full episode of PBS Nature's Silence of the Bees, which looks at a recent phenomenon dubbed Colony Collapse Disorder (CCD).

An interview about koala communication, vocalization, and social structure with Dr. Bill Ellis, head of The University of Queensland's Koala Ecology Group.

Information about the eucalyptus leaf-eating marsupial Phascolarctos cinereus.

A fight erupts between two koalas after one of the males invades the other's territory.

A baby koala consumes his mother's pap, a secretion that will give the joey the bacteria needed to digest eucalyptus leaves.

Cracking the Koala Code explores the day-to-day dramas of an extended family of koalas, seen through the eyes of the scientists studying their every move and vocalization. Watch a preview of the film.

Two lionesses attack an unfamiliar and aggressive male who approaches their small pride. Watch a scene from the PBS Nature film The White Lions which premieres May 9, 2012.

One of the white cubs, now almost a grown lion, takes on a clan of approaching hyenas in South Africa's Kruger National Park. Watch a scene from The White Lions which premieres May 9, 2012.