Journey to the Land of Marsupials: Pouched Mammals of Australia
I finally arrived in Cairns, Australia about 30 hours of airports and airplanes after I left Newark Airport in the USA. I was traveling with a small group of teachers for a course on Australian flora and fauna. Because we crossed the International Date Line, we left Newark on a Sunday and arrived in Australia on Tuesday afternoon. Yes, one whole day just seemed to vanish below the airplane wings somewhere over the Pacific Ocean.
Australia has a long history of isolation from other continents. Australia became isolated from the rest of Gondwanaland (Pangea) around 100 million years ago and has been drifting north approximately 55 mm per year (Bennett, 2000). When Australia separated from the ancient super-continent, many marsupial species got isolated on Australia, and then diversified into many more species that fill a variety of ecological niches. As a result, there are more species of marsupials in Australia than anywhere else in the world-- about 144 species (Bennett, 2000).
Marsupials are mammals: they have fur, bear live young rather than laying eggs, feed their young with mother's milk from a nipple, and show quite a bit of parental care --sometimes for longer than a year. What makes marsupials unique among mammals is the female's pouch where the young finish their development after birth.
A young marsupial is born after only a few weeks as an embryo. It may be less than one centimeter in length and very helpless. It has large front paws that it uses to climb through the mother's fur to reach the pouch. The mother may lick a pathway through the fur to guide the hairless, pink, worm-like youngster in its long journey to the pouch. There it must attach to a nipple to receive nourishment from milk. When old enough, the "joey" leaves the pouch to explore, but returns to the pouch for safety, warmth, and food.
During a trip to Australia, it would be virtually impossible to avoid seeing any marsupials. Here are some of the marsupials I saw during my 3-week visit, and some photos you may view:
- Eastern gray kangaroo
- Tree kangaroo
- Rock wallaby
- Pretty-faced wallaby
- Common wallaby
- Red-necked pademelon
- Red-legged pademelon
- Sugar glider
- Ring tailed possum
- Common brushtail possum
- Herbert's River ringtail possum
- Coppery brushtail possum
- Tasmanian Devil
I noticed that many of the female gray kangaroos had joeys in their pouches. We fed kangaroos in Steve Irwin's (Crocodile Hunter) Australia Zoo, but we were told not to try to feed or touch joeys in pouches because the mother might try to protect her baby and so hurt us.
My favorite marsupial is probably the Koala. Here is a photo of a Eucalypt tree, the main food of koalas. Koalas smell each branch to decide if the leaves are good to eat. Eucalypt oils give the leaves of each species a characteristic odor. These oils are also toxic. Koalas have bacteria in their digestive systems to help them digest the Eucalypt leaves that are of poor nutritional quality and contain these toxic oils. They have strong incisors to snip off leaves and molars with cutting edges that slice leaves into small pieces. In this photo, my friend Karen is holding a koala, which has the thickest fur of all marsupials.
My next Australia Journal Account #2 tells about other special marsupial species I observed in the wild and at a great zoo.
Bennett, Jane. Watching Wildlife: Australia, First Edition. Lonely Planet. Sept. 2000.
Pascack Valley HS
Jackie Willis, Ph.D.
Montclair State University
Upper Montclair, NJ
Special thanks to Professional Resources in Science and Mathematics (PRISM) at Montclair State University and Dr. Jackie Willis for making these ecology trips possible and for sharing her wealth of knowledge, her expertise, and her photographs with us.