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NATURE: Cracking The Koala Code

Airs Wednesday, January 16, 2013 at 8 p.m. on KPBS TV

Credit: Courtesy of Wild Fury Pty Ltd.

Above: Koala with joey on a tree, learning to adapt to the consequences of urbanization and habitat erosion.

Loud bellows ring out from a small pocket of forest surrounded by dense suburbs and busy roads in Brisbane, Australia. It’s mating season for koalas. Their thunderous roars are difficult to reconcile with the familiar perception of them as cuddly creatures.

But it turns out their world is in fact far from cute and cuddly. Rather it is filled with social pressure, conflict, disease, overcrowding and the external stresses of living in the middle of what amounts to an alien world.

Predominantly slow-moving, energy-conserving koalas are not exactly well-equipped to handle speeding traffic and packs of dogs, or the consequences of encroaching urbanization. For a real change of pace, NATURE enters the world of urban koalas trying to adapt to life in the fast lane.

"Cracking The Koala Code" explores the day-to-day dramas of a number of urban koalas, seen through the eyes of the scientists studying their every move and vocalization.

Fascinating social dynamics include territorial displays, vicious fights, and the surprising mating strategies of traveling male koalas, rogues who truly play the field. New science even “cracks the koala communication code,” providing insights into their basic language and social structure.

“People love koalas, yet there is a great deal about them they would find surprising,” said Fred Kaufman, series executive producer and recently named recipient of International Wildlife Film Festival’s Lifetime Achievement Award. “Koalas may seem docile and sweet, but they are really quite active and can be very aggressive and loud. Viewers will get a whole new perspective after watching this film.”

Biologists Cathryn Dexter and David Black have been studying koalas in the Brisbane suburb of Petrie in an effort to understand the social interactions within an urban koala colony.

They have been tracking the movements of more than 70 koalas, monitoring their health, providing medical assistance when necessary, and compiling data they hope will be useful in creating safe passageways through high traffic areas for the animals.

Elsewhere in Queensland, biologists Bill Ellis and Sean Fitzgibbon are engaged in research sponsored by the San Diego Zoo to learn more about the koala social system, mating habits and communication.

Using 3G solar-powered mobile phones to record female koala vocalizations, and using those recordings in the field to evoke male koala responses, they have managed to decipher some of the koalas’ communications.

Their studies suggest that female koalas may be able to tell which males are bigger, and therefore more attractive, by their bellows alone.

Through DNA analysis, the team also made a most surprising discovery – that traveling males sire about 40 percent of the offspring in koala groups, despite the best efforts of the group’s resident dominant male.

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Preview: Nature: Cracking The Koala Code

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Follow individual koalas from a small social group on an Australian island to learn just how a koala manages to survive and thrive on a diet poisonous to almost all other herbivorous mammals. From the miracle of marsupial birth to tender moments of discovery between mother and newborn joey, encounters with threatening forest creatures, battles between rival males and the complex chorus of bellows and grunts that have become so important to science — join leading scientists as they unravel just what a forest needs to support a healthy population of koalas by listening to these marsupials themselves and cracking the koala code.

Cracking The Koala Code: Preparing for a Eucalyptus Diet

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Watch Preparing for a Eucalyptus Diet on PBS. See more from Nature.

A baby koala consumes his mother’s pap, a secretion that will give the joey the bacteria needed to digest eucalyptus leaves. Watch a scene from "Cracking the Koala Code."

Cracking The Koala Code: A Koala Roams the Suburbs

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Watch A Koala Roams the Suburbs on PBS. See more from Nature.

A male koala roams the Australian suburbs in search of a mate to produce offspring. Watch a scene from "Cracking the Koala Code."

Cracking The Koala Code: A Battle for Territory

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Watch A Battle for Territory on PBS. See more from Nature.

A fight erupts between two koalas after one of the males invades the other’s territory. Watch a scene from "Cracking the Koala Code."

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