The Common Brushtail Possum is also abundant, and a nuisance to farmers and fruit growers as it has adapted too well to cleared forest land. Although they are ground feeders generally, they have a love of domestic fruits. It spends the day sleeping in tree hollows and the young are carried at first in a pouch and then on the mothers back. The Brushtail is also the major predator of the Glossy Black Cockatoo's chicks and eggs. This animal has a waddling gait if seen walking on the ground but if it goes into a tree or onto a power cable it becomes a skilled aerialist.

Koalas were introduced here in the 1930's to build a colony in the event of the extinction of the mainland Koala population. The Koala is an icon of Australia and thrived on the island with a lack of predators and an abundance of Koala preferred gum leaves, these being from the Manna, Swamp and Blue Gum. The Koala eats about 0.5 kg (1 lb.) of leaves each day.

Their numbers increased so well that the Koala was eating its way to starvation with the population of Koalas here reaching over 5000. A programme was undertaken to reduce the numbers to a sustainable population. 2500 were sterilised and 850 were relocated to mainland sites. The birth rate has slowed and the Koala is now at comfortable numbers on Kangaroo Island although monitoring of numbers will continue. They can be viewed at Hanson Bay, Cygnet River and Flinders Chase National Park.

The only endemic species to Kangaroo Island is represented by the Sooty Dunnart. A shy and small marsupial, it was found in 1969 in a mallee scrub area. Not many have been found but it has been identified as a new species and as the only endemic species to Kangaroo Island it is worthy of mention.

Monotremes

Short-nosed Echidnas are a blonder sub-species of a mainland monotreme.  These animals lay eggs and are covered in sharp spines like a porcupine. They burrow into ant and termite mounds for food and there young are hatched after incubation in a termite mound. The young are called 'puggles' and are carried by the mother in a pouch for about 50 days where they suckle from milk patches. They are then placed in a nursery burrow and the mother returns about every 6 days to suckle them for the next 6 months. They are then left to fend for themselves, as there is no interaction between adults and young after this. Echidnas are often seen walking beside roads and as they are nocturnal feeders are seen best in the early evenings but can be seen at any time of day, especially towards the western end of the Island.

15 Platypus were introduced successfully between 1928 and 1948. They remain on Kangaroo Island in the Flinders Chase Conservation Park. Safe from predators their exact numbers now are unknown. An interesting mammal that lays eggs in burrows on the sides of ponds and slow moving rivers. They eat worms and small crustaceans that live in the mud. They are expert swimmers and their movement is much like that of an otter. An unusual and secretive animal it is often referred to as the 'Duck Billed Platypus" because of its leathery bill shaped much like a ducks through which it senses the movements of worms and yabbies (shrimp-like crustaceans). It has webbed feet and a flat tail that resembles a beaver. Sitting quietly by a pond (billabong) in the Flinders Chase National Park often results in a view of these fascinating animals.

Marine Mammals

There are 6 kinds of marine mammals associated with Kangaroo Island.

The Australian Sealions are found on the South coast. Guided tours take people into the heart of the colony of about 600 seals at Seal Bay National Park. The Australian and New Zealand Fur Seals can be seen at Admirals Arch near Cape du Couedic. Commonly these animals can be seen at other coastal locations along the South Coast. The seals were nearly hunted to extinction, are now protected and increasing in numbers.