Bluffton Today -

Tasmanian marsupials and monotremes: Observing some of Australia's most iconic species

  • Courtesy of Dr. Barry E. Wright A pair of Eastern Grey kangaroos feeding.
  • Courtesy of Dr. Barry E. Wright Wombats are the world's largest burrowing animals.
  • Courtesy of Dr. Barry E. Wright A sign at Angelsea Golf Club tells visitors they cannot access the course to view kangaroos.
  • Courtesy of Dr. Barry E. Wright Koalas are Australia's only climbing marsupials.
  • Courtesy of Dr. Barry E. Wright Tasmanian devils are designed to generate the strongest bite per body mass of any mammal predator.
  • Courtesy of Dr. Barry E. Wright A rare white Bennetts wallaby.

Waters of the Pacific Ocean and animal endemism are defining characteristics of the island nations of Oceania. According to the World Wildlife Fund, fully 84 percent of its mammals, 45 percent of its birds and 89 percent of its fish species can be found only in the Commonwealth of Australia.

As lifelong nature enthusiasts and experienced volunteers in wildlife conservation programs, we were pleased while in the state of Victoria to have the opportunity to begin observing two of their iconic species, marsupials and monotremes.

Like all mammals, marsupials and monotremes are warm blooded vertebrates who nurse their young with milk and have hair or fur on their bodies. Unlike placental mammals who nourish their babies through the specialized organ in the mothers’ wombs for extended periods of time until their birth in an advanced state, marsupials gestate their babies for a short 5-6 week period. Because these offspring are born in a fetal state, the newborns are essentially helpless and, after crawling into their mother’s pouch and latching onto a teat, will require nursing and nurturing within the pouch for 12-16 months to complete their post natal development.

Best known of the 300 recognized marsupial species are opossums, kangaroos, koalas, Tasmanian devils, wallabies, and wombats. Monotremes are the most primitive of all living mammals. These animals, like reptiles and birds, reproduce by laying and brooding eggs instead of by live birth. Mothers have mammary glands but no nipples so after a three week gestation, the newborns lick milk off her fur and mature in a temporary maternal pouch. Duck billed platypus and four kinds of spiny anteaters are the only two remaining varieties of living monotremes.

Aussies’ friendliness and senses of humor are legendary. When a tourist in Melbourne approached a local and asked, “Will I be able to see kangaroos on Bourke Street?” our friend replied, “Depends on how much you’ve been drinking, Mate.” In a country whose land area makes the sixth largest in the world but whose 22 million people rank as the 53rd most populous nation, one doesn’t have to travel far from urban centers to spot any of the estimated 40 million resident kangaroos.

About an hour down the Great Ocean Road from Melbourne, for example, is the coastal village of Angelsea where a mob of some 50 to 100 Eastern Grey kangaroos happily live at and around the local golf club. Of the 47 species of kangaroos, Eastern Greys are one of the largest varieties and, on average, stand 6 feet tall and weigh 150 pounds. All kangaroos are herbivores who graze and swallow without chewing to later regurgitate the cud and then eat it. Roos move forward by 30-foot long hops at rates of speeds averaging 40 miles per hour. After extensive study, zoologists have determined that kangaroos are not territorial, rarely vocalize unless reassuring joeys or mates and fight only for mating rights.

Separated from the southern mainland by Bass Strait, Tasmania is the most southern island state of Australia. Its relative isolation has resulted in its having spectacular unspoiled natural beauty and rugged wilderness. Tasmania is renowned for outdoor experiences such as bushwalking, rock climbing and rappelling, snorkeling through kelp forests along the underwater trail, sea kayaking and skydiving.

Because of our interest in observing indigenous animals in their native habitats, we headed to northwest Tasmania’s Tarkine Wilderness to enjoy a multi-day bushwalk Tassie-style. The Tarkine has unique and highly diverse ecosystems which contain the largest intact tract of temperate rainforest in the southern hemisphere, several species of eucalyptus forests, coastal heathland, button grass plains, dolerite rock cliffs and wild beaches.

We’d traveled only a short time with our local guide through open eucalypt woodland when we heard sounds best described as crosses between snores, snorts and belching coming from overhead . We looked up and there, securely wrapped around a eucalyptus branch, was the unmistakable pear shaped grey furry body of a koala bear.

Koalas are often described as bears because their big black nose and round ears reminded early settlers of teddy bears, but they are, in fact, Australia’s only climbing marsupials. Tassie koalas are about 30 inches long and 30 pounds and after storing excess unchewed eucalyptus leaves in their cheek pouches, they spend up to 18 hours a day resting alone or in loose colonies high up in trees. When they descend to ground to change trees or to consume pebbles to aid their digestion, koalas move using a kick-like form similar to that used by rabbits.

As we moved through heathland and coastal scrub early on a cold and overcast day, we came across a usually nocturnal wombat warming himself on a towel remnant left on the river bank. At an average 40 inches long and 70 pounds, wombats are the world’s largest burrowing animals and the second largest marsupials after kangaroos. Like carnivorous North American badgers, herbivorous wombats are short, stocky animals which use their muscular front legs and sharp claws to dig extensive underground networks of burrows.

Unlike other members of their class, however, these marsupials feed almost exclusively on sedge and bark so the two incisors in their upper jaw continue to grow longer throughout their lives. While most marsupial pouches open upward at the top, koalas and wombats have the anatomical adaptation of pouches which open downward toward the hind legs.

Carnivorous marsupials are among the most successive hunting animals and Tasmania is the last remaining home to four of the largest carnivorous marsupials in the world. The most famous animal of Tasmania, of course, is the Tasmanian Devil, whose piercing screech has to be one of the scariest sounds ever heard. With their thick head and neck and jaws which open a full 80 degrees, devils are designed to generate the strongest bite per body mass of any mammal predator. Devils are, technically, crepuscular, but by using the whiskers on their faces and heads they can successfully locate food in the dark.

Similarly, while they are adapted to easily detect motion, they have difficulty seeing stationary objects. Despite their average size being about 2 feet long and 15-20 pounds and their propensity for attacking food with uncommon ferocity, Tasmanian devils are opportunistic hunters and prefer to eat carrion than running down fleeing game. Once satiated, these marsupials become lethargic and waddle slowly back to their dens in dry caves.

Despite having some amazing evolutionary adaptations such as their black and white flash pattern of fur, devils have low genetic diversity. These carnivores are considered to be critically endangered as a result of their increasing death rates from a highly contagious transmissible cancer known as Devil Facial Tumor Disease. Eastern quolls, which our guide quipped resemble a cross between a cat and an opossum, are the closest relative to devils and they too are so critically endangered that the naturalist hadn’t seen one in the past six months.

Wallabies are the smallest members of the kangaroo family and usually stand about 2 feet tall and weigh about 40 pounds. Throughout Tasmania their home ranges overlap with the devils’. While we were traversing some open bushland in a rocky area, we spotted a rare white Bennetts wallaby. While not genetically true albinos, white furred wallabies’ coloring mean they lack natural camouflage so to protect against predation, they tend to congregate when grazing. Other varieties of this species are classified by the habitat and wallabies are one of the most commonly seen marsupial on the island.

With its duck bill, beaver tail and otter body with webbed hand and feet, platypuses have been described as the ultimate animals designed by a committee. Electroreception is the biologic ability to detect natural electric fields. This sensory adaptation by which to locate objects and food is well known in dolphins, fish and amphibians, but platypuses are the only group of land mammals known to have evolved as electroreceptive.

Using their sensitive bills, these semiaquatic carnivores hunt shrimp and crawfish underwater for up to 10 minutes at each effort to eat their daily food requirement of 20 percent of their body weight. Male platypuses are also one of the rare venomous mammals. Delivered via a defensive strike of the ankle spur, platypus venom is not lethal to humans but it is sufficiently potent to cause men severe pain and incapacitation for months. Platypuses are highly specialized, delicate and shy animals who are also endangered so we were lucky to have a glimpse of one swimming at dusk.

To travel in any wilderness is a privilege and we are indebted to our Tasmanian host environmentalists who allowed us to experience their biosphere. As our guide said: “The best ‘Leave No Trace’ travelers are those who arrive prepared to cope with sudden changes in conditions, respect our land and give our wildlife space. If you come to Tasmania to be awed by the honor of our observing animals’ behavior and if you are willing to back off at the first sign of their awareness of humans or signs of stress, you will always be welcome.”

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