Jounior Observer | Sunday Observer.lk

The two animals we introduce today are members of the Macropodidae family and are native to Australia. Macropods are marsupials and include kangaroos, wallabies, tree kangaroos and quokkas. The term macropods comes from the Greek word for `long foot’ and is appropriate as most members have very long, narrow hindfeet with a distinctive arrangement of toes. Macropods vary in size.

The quokka (Setonix brachyurus), a small macropod which is the size of a large domestic cat, is the only member of the genus Setonix. It is found in South West and Western Australia and is a protected species in the islands, where it’s found in large numbers.

In fact, Rottnest Island, which is 10 kilometres away from Perth, the capital of Western Australia, has been so named after these animals. It is recorded that a Dutch explorer named Dirk Hartog who was sailing past the island saw these small creatures and thought they were rats, because they strongly resemble rats.

So, the island was called the Rat’s Nest island and later became known as Rotten Nest island. This too had eventually been changed to Rottnest, as the island is known presently.

Let’s check out this animal’s appearance to understand why the Dutch explorer mistook these little creatures for rats!

The quokka as we explained earlier is no bigger than a cat with a head to body length of 40-54 cm. The tail is about 25-30 cm and is considered to be rather short for a macropod. There isn’t much hair on the tail like that of a rat and perhaps this contributed greatly to give the Dutch explorer the impression that these animals were large rats.

The quokka has a rounded body which gives it a stocky appearance, a flat face, short broad head, rounded ears covered with fur, long hind legs (about 10 cm long), which are covered with stiff hair and a snout. It weighs about 2.5 to 5 kg. Its fur is coarse and grizzled brown on top, fading into buff colour on the underside. Dark stripes are visible on the forehead.

The quokka is a herbivorous and nocturnal animal like the other members of the Macropodinae family. Its diet comprises grasses, sedges and succulent foliage. When necessary it also eats fruits, nuts and small insects, on the ground or on trees found in the long grass or shrublands of the temperate climate it lives in.

Fact file on Macropods

* Macropods are herbivorous; some are browsers, but most are grazers. Teeth are equipped for cropping and grinding up fibrous plants.
* Macropods have specialised digestive systems.
* The ancestor of all kangaroos is believed to be a small arboreal marsupial which looked like the present day possum of Australia.
* Kangaroos (Macropodidae) grow to varying sizes, but all have small heads. The grey giant kangaroo (Macropus giganteus) grows to a length of three metres while the red giant kangaroo (Macropus rufus) is slightly bigger.
* The wallaroo (Macropus robustus) is a medium sized kangaroo which is also called the mountain kangaroo. It lives in eastern Australia in the hills. In times of drought, it digs to depths of about a metre in search of water.
* Tree kangaroos are solitary animals, except during the breeding period. They sleep 60 per cent of the day .

It can climb trees like tree kangaroos. The quokka moves like a kangaroo in long and short hops. Being sociable and gregarious animals, the quokkas are found converging in large groups, numbering 100 to 150 adults at waterholes and places where food is available in plenty. Even though like all living creatures the quokka too needs water, the animal can survive without it for days because it has a special ability to recycle a certain amount of its waste product. The quokka is active at night, but sleeps during the day in the shelter of dense vegetation.

After a gestation (pregnancy) period of four weeks, the quokka gives birth to a single baby which is called a joey. It lives in the mother’s pouch (all marsupials have such pouches) and suckles mother’s milk for about 26-30 weeks. After this time period passes, the joey leaves the protection of the pouch, but continues to suckle for another eight to 10 weeks.

The males which are larger than the females are called boomers and the females of quokkas are known as fliers. The current population in Rottnest Island is estimated at around 10,000.

The tree kangaroo, the other member of the Macropodidae family introduced today is found in the rain forests of Papua New Guinea and nearby islands and far northern Queensland, usually in mountainous areas.

Unlike the world’s most well-known marsupial, the Australian Kangaroo, the tree kangaroo is well adapted to an arboreal life with stronger forelimbs for climbing, short and wide feet, sharper claws on all feet and rubbery soles for better grip. While orthodox kangaroos cannot move its feet independently (one at a time) the tree kangaroo can do so. The tree kangaroo has massive hindlegs and an exceptionally long tail which it uses as a rudder, for balance though it’s not prehensile. (has no gripping ability)

The tree kangaroo is a large, heavy bodied marsupial with a weight of about 23 lbs and a head to body length of 26 inches. Its tail is long and cylindrical and equal to its head to body length generally. The tree kangaroo’s ears are short and round (not long like the big grey kangaroo we know). Its soft fur coat is short and grey coloured on the back and lighter on the underside (belly area). Its nose, toes and the tip of the tail are black.

The tree kangaroo is rather slow and clumsy in its movements on the ground; it moves at walking pace and hops rather awkwardly, leaning its body far too forward, balancing on the tail. However, it is bold and agile on trees. It’s an expert leaper and downward leaps up to nine metres (29.5 ft) from one tree to another have been recorded by researchers. It has the exceptional ability to jump to the ground from heights of about 18 metres (59.0 ft) or more without getting hurt.

The tree kangaroo eats mostly leaves and fruits, but when available, it also eats grains, flowers, sap, bark, eggs and young birds. Its teeth are adapted for tearing leaves and its large stomach functions as a fermentation vat, somewhat like in eutherian ruminant herbivores, though the arrangement of the stomach is different. This means the bacteria in the stomach breaks down the fibrous grass it eats.

The female gives birth to a single young (joey) after a gestation period of 39 to 46 days (longest of any marsupial). The joey attaches itself to a nipple in the pouch (which contains four mammae) and suckles for 90-100 days. At 250 days, the joey is big enough to peek out of the pouch, and by 300 days it leaves the pouch for the first time. But, it takes another 50 days or so before the joey leaves the pouch permanently to survive outside.

There are about 10 to 12 species of tree kangaroos and some of these are the grizzled tree kangaroo, Lumholtz’s tree kangaroo, golden mantled tree kangaroo, Bennett’s tree kangaroo and the lowlands tree kangaroo.

Only two species (Bennett’s tree kangaroo and Lumholtz’s tree kangaroo are found in Australia).Tree kangaroos are threatened by the loss of their natural habitat-rainforests, and many programmes are under way to protect them. Its lifespan in captivity is said to be around 14 years.