A Rescued Musky Rat Kangaroo
A Rescued Musky Rat Kangaroo Photo By M.Searle

Many visitors to the Daintree Rainforest never get a glimpse of this primitive chocolate brown grey-headed daytime marsupial, but for those who do the experience is often a memorable one.

Musky Rat Kangaroos are endemic to the wet tropics living in both low and highland rainforest. All species of kangaroo belong to the macropod family. Musky Rat Kangaroos are the last surviving members of a prehistoric Gondwanan lineage of macropods (Greek for large foot) that broke away from the rest of the macropod family approx. 45 million years ago; their nearest relative became extinct in Victoria 4 million years ago during an ice age. They evolved from possum like tree dwelling ancestors and have retained some of their features to this day. Such as five toes on each foot (all other macropods have four toes) and a great toe or hallux on their hind feet. This mobile semi-opposable toe lets them climb along logs and branches a set of grooves on the pads of their feet helps them grip. They also have retained a second set of incisors allowing them to eat insects as well as plants. With blade like premolar teeth, they tear open the tough exo-skeletons of insects before the incisors tear apart the flesh. They have simple stomachs and cannot digest the structural carbohydrates in the cell walls of plants as well as other macropods that are foregut fermenters and can chew the cud. Their tails are hairless and scaly (so are their feet) and not used as a support like other kangaroos tails. Instead, they are semi- prehensile and used to wrap around leaves and sticks that are collected and carried away to become nesting materials. They do not hop like other kangaroos but have more of a gallop style of moving around using both forward and hind feet instead of only hopping using the back legs like their kangaroo cousins.

They are the smallest kangaroos in Australia approx. 23cm long in the body with a tail that is about 14cm long. Weighing around 500g full-grown. Unusually for kangaroos, they are diurnal (daytime animals) and are one of only two Australian marsupials that choose this life style, the other is the Numbat. Most others are crepuscular (active at dawn and dusk) or nocturnal. Unlike the Numbat that lives on a diet of ants and termites, Musky Rat Kangaroos prefer more variety in their diets eating fruits, fungus, seeds, lichens, flowers, insects and even the soft inner bark of some tree species. They eat at least 44 species of plants from 23 families including the flowers of the Austrobaileya vine, a very rare primitive flowering plant endemic to the Daintree region. Their feeding habits help in rainforest regeneration as they eat the seed and the kernel of the seed as well as the fruit, even picking seeds out of cassowary droppings. This ensures that plant species do not get the chance to become-localized and a greater variety of plants can exist in the rainforest. As well as destroying, they also disperse carrying large seeds too big for most birds far away and burying them for later food reserves in the cooler months. If they forget about the seeds or die before coming back for them then the seeds have been planted giving them the best chance to germinate away from the parent tree. Musky Rat Kangaroos and the Southern Cassowary are the only two animals essential to seed dispersal for many species of plants in the rainforest.

Recent fossil discoveries of Musky Rat Kangaroos have found that they have always existed in rainforest habitat, never adapting to any other eco systems like temperate rainforest or grasslands. Multiple species of Musky Rat Kangaroos existed 20 million years ago when rainforest was wide spread but today just one species in North Queensland remains.

They use their semi-prehensile tails to wrap around collect and carry leaves and sticks to build nests at the base of buttress roots or in clumps of wait-a-while. Breeding season starts in October when the male’s testes swell and enlarge dramatically in advance to the wet season making them more aggressive, shrinking again in April when the dry season starts. Gestation takes 19 days and unlike all other kangaroos there is no embryonic diapause so they do not breed continuously, instead they have a 5 month period with no breeding followed by 7 months of breeding. Females are sexually receptive with estrous cycles of 26 days and carry pouch young for 5 to 6 months from March to October so that the young leave the pouch in the wet season when fruit is abundant. They can raise 1 to 3 joeys in a single litter with the young being left behind at the nest after leaving the pouch until December and weaned by January.

Musky Rat Kangaroos live in densities of 140 – 450 individuals per kilometer squared. They have small home ranges of 2.1 hectares for males and 1.4 hectares for females with male territories overlapping females. They form small feeding groups of 2 – 3 animals at the base of trees when food is plentiful. Their life span is usually about 4 years and they fall victim to around eight predators, which are the dingo, scrub or amethystine python, grey goshawk, Rufus owl, lesser sooty owl, spotted tail quolls, domestic cats and dogs. Rainforest clearing has a major effect on population size and distribution and make the Musky Rat Kangaroo a species that is an ambassador to rainforest conservation both in Australia and around the world.

Resued Musky Rat Kangaroo view 2

Comments (1)

  1. Jasmin

    Reply

    What a fascinating & marvellous little creature! I didn’t know they were in the same category of importance as the Southern Cassowary when it comes to seed spreading/rainforest regeneration!
    I learnt a lot from this well articulated article,
    Thanks for taking the time to write it.

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