Species Fact Profile: Koala (Phascolarctus cinereus)

                                                                        Koala

Phascolarctus cinereus (Goldfuss, 1817)

Range: Eastern and Southern Australia

Habitat: Temperate and Tropical Open Forest, Woodland

Diet: Eucalyptus Leaves

Social Grouping: Primarily solitary, but sometimes form small groups. 

Reproduction:  Breed spring and early summer.  Females usually breed alternating years, determined by availability of food.  Gestation is 33-35 days.  Single joey (sometimes twins) is 0.5 grams at birth, very poorly developed.  The joey emerges from the pouch at 6-7 months, weaned at one year.  Sexually mature at 3-4 years old.   

Lifespan: 13-18 Years

Conservation Status: IUCN Vulnerable

• Body length 60-85 centimeters, weight 4-15 kilograms.  Males are up to 50% larger than females.  Males and females can also be differentiated by their more curved noses and chest glands (visible as hairless patches).  Stocky body with powerful limbs, vestigial tail
• Fur is thicker and longer and the back, shorter on the belly.  The ears are thickly furred inside and out.  The belly is white, as is the rump, while the fur on the back is a gray or brown.  The fur is very insulating and resistant to wind and rain.
• The forepaws (“hands”) have two opposable digits to help grasp small branches.  The second and third digits of the hind-paws are fused and serve as a grooming claw.  Paws have friction ridges to assist with climbing.  A cartilaginous pad at the base of the spine keeps the animal comfortable while resting in the trees.
• Eucalyptus are of low nutritional value and high in toxicity.  Several adaptations to the diet, including specialized teeth for shredding the leaves, cheek pouches for storage,  and the production of a chemical which breaks down the toxins of eucalyptus in the liver.  Very low metabolic rate, half that of a typical mammal
• Home ranges are small and overlap heavily, but do not interact much.  Males may become territorial and dominate others, marking their territory by scent marking with their chest glands, making loud, low-frequency bellows.  Males may fight, by try to avoid it since they don’t have surplus energy
• Predators include dingoes and large pythons, while large birds of prey may take the young.  Sometimes killed by falls from trees, though often are able to recover.  Slowness leaves them vulnerable to bushfires.  Ultimate cause of death for many koalas is starvation caused by the wearing down of their teeth, which usually begins at about 6 years of age.
• Common name comes from the Aboriginal Dharug word gula meaning “no water,” which reflected the belief that the animals did not have to drink, ever.  The genus name comes from the Greek “Phaskolos arktos” for “pouch bear” and the Latin “cinereus” for “ash-colored”
• Historically hunted for their fur, leading to local extirpation.  Hunting no longer is practices, but now numbers have rebounded to the degree that population control is needed in some areas (outcry against culling, instead translocation and sterilization).  Sanctuaries for the species have been established across its range
• Primary threat it habitat loss and fragmentation.  Range has shrunk by 50%.  Koalas were the very publicized face of the 2020 bushfire crisis in Australia
• Major symbol of symbol of Australia and key component of the ecotourism industry there.  Source of popularity its teddy-bear like appearance.  Depicted in cartoons (Kwicky Koala, Noozies), mascot of sports teams, featured on coinage.  Sometimes sent on loan to foreign zoos similar to the “panda diplomacy” employed by China
• Australian Aborigines depicted the koala in Dreamtime stories, depicted in rock art.  Historically hunted it for food.  Modern Australian folklore tells of the “drop bear,” a mythologized bloodthirsty koala that drops on people from above

                    

Zookeeper's Journal:  It's hard to believe, but there was a time when no one really liked koalas.  The first European naturalists to see them found them grotesque and stupid; settlers were afraid of them and thought they might be dangerous.  I wonder what they would think of them now, when the koala is one of the most beloved species on the planet and an internationally recognizable symbol of Australia?  Today, the koala is one of the most famous “zoo animals” in the world… even if few zoos actually have one. Like most American zoo lovers, my first encounter with a koala was at the San Diego Zoo.  For a long time it was the only zoo in the world to have the species outside of Australia.  Koalas only appeared in US zoos starting int he 1920s, with their ability to thrive being directly connected to the ability of a zoo to have a good year-round supply of fresh eucalyptus.  Not surprisingly, they are mostly found in zoos in the warmer parts of the country, with San Diego still having the majority of them.  Apart from the fussy diet, koalas don't ask for much as far as exhibit animals go.  They just... sleep on a perch, which is pretty much what they do in the wild.