In the dim light of 5:10 a.m., a golfer hit practice balls on the Townsville Golf Club, his face so screened by the receeding darkness that I was unable to ascertain if he was young or old. Beneath the crowns of two tall gum trees at the edge of the club lawns, avian whitewash spattered the bitumen path on which I walked, the concentration of droppings far denser than I’d ever seen it before under those favoured roosting trees. When I looked up into the open canopies of the eucalypts, I spotted the pale, curved-beak lumps of white ibises and the smaller but more numerous shapes of little black cormorants that were solid black against smoky grey sky. After I passed by, the cormorants lifted into the sky and flew in well-spaced formation, as though they were a squadron of fighter jets on lazy maneuvers.
I walked in the Ross River Parkway for an hour, refreshed by wind that jiggled fringed palm leaves beneath a sky blanketed with cloud, and serenaded by the songs of lorikeets, magpies, and nutmeg mannikins. The rising sun infused lilac clouds with pink-gold light and gilded the broad crowns of mango trees. When I retraced my steps, it had already begun burning off the cloud. In this country, that golden orb rules.
Koala, Billabong Sanctuary, Townsville, Queensland (© Vilis Nams)
In the sphere of Australian wildlife, certain animals may be said to ‘rule.’ One of these is definitely the koala, that cute, tree-dwelling marsupial whose appearance makes you want to pat and cuddle it, a response that may be triggered by the fact that the koala shares similiar body proportions – big head, short limbs, medium-sized body – to those of a human baby.1 In his book Koala: Origins of an Icon, Stephen Jackson includes the following quote taken from a travel memoir written by T. Wood and published in 1934: “He keeps his little round eyes fixed on yours, blinking solemnly; and all you can do is wriggle with delight at your discovery that in this disillusioned grown-up world you have met the most lovable toy of your childhood come to life.”2
In February, when Vilis and I visited Billabong Sanctuary just outside of Townsville, the koalas enthralled us. None were asleep, which was in itself unusual, since koalas sleep for around 20 hours each day.3 The alertness we observed was likely due to anticipation of feeding time, since the koalas’ caretakers soon arrived with bundles of fresh-cut eucalyptus branches placed in cans partially filled with water to hydrate the gum branches. The koalas nimbly plucked leaves from the branches with their forepaws, which, unlike our hands, possess not one but two opposable thumbs side by side and three fingers opposite them.4 As well, despite their plump, lumpy bodies, the koalas moved surprisingly quickly along branches to position themselves to feed. This was in early morning.
Koala, The Forts Track, Magnetic Island, Queensland (© Vilis Nams)
In contrast, the two koalas Vilis and I observed in the wild in gum trees alongside The Forts Track on Magnetic Island, offshore from Townsville, during late afternoon in early Ausgust were notably lethargic. The first – which was perhaps roused from its sleep by the excitement I emanated at finally spotting a wild koala – stared down at us blearily from squinty eyes, gave one hind leg a good stretch, and then slowly pulled itself hand over hand higher into the ironbark, where it began to feed. The second koala was a snoozing lump on a tree branch overhanging the trail, the ground beneath it littered with cellulose-filled droppings.
In my reading, I learned of an intriguing triangle of facets of a koala’s life. First, there’s the significant amount of time spent sleeping each day, as noted above. Second, a koala possesses a small brain with few convolutions on its surface.5 And third, the leaves of eucalypts possess little nutritional value and several metabolic toxins.6 So, how are these related? Because gum leaves yield so little nutritional energy, and because koalas must spend part of the energy they do obtain from the leaves to remove leaf toxins from their systems, they have an extremely tight energy budget for daily activities.7 Sleep is a low-energy activity, so they do a lot of it.7 On the other hand, high-functioning brain activity consumes huge amounts of energy. Tim Flannery of the Australian Museum suggested that the koala’s small and simplified brain may be an adaptation which reduces energy demands within an environment dominated by food sources that supply little energy and require energy to detoxify.8
While on the topic of foods, I will mention that I (and undoubtedly many others) were wrong in thinking that koalas consume the leaves of only a few species of Eucalyptus. In fact, throughout their entire geographic range, koalas eat the leaves of more than 30 gums species and in some areas eat to some extent the leaves of other trees, such as she-oaks and paperbarks.9 However, within each of the states they inhabit (Queensland, New South Wales, Victoria, South Australia), koalas are indeed selective, preferring the leaves of only 3-6 gum species.9
Koalas are such intriguing creatures. They may live into their teens.10 The males growl and bellow to other males, which is thought to be a means of spacing, and fight both in trees and on the ground during breeding season.11 After young koalas leave their mother’s pouch at around 9 months of age, they become velcro-kids and cling to her back until fully weaned and independent.12 Koalas rarely drink water, which may be how their appellation was derived, since in several Aboriginal languages the words used to name these animals means ‘no drink.’ 13
Koalas are such Aussie icons, it’s hard to believe they came close to extinction.14 For tens of thousands of years before Europeans arrived on this continent, koalas had few animal predators, but were hunted by Aboriginal peoples.15 With the decimation of the Aboriginal population by Europeans in the late 18th and early 19th centuries, koala populations were no longer kept in check and began to increase markedly.15 Settlers started hunting koalas in the mid-1850’s, and eventually koala pelts became hot items in international fur trade circles.15 Millions of koalas were killed as a result,15 until public outrage across the nation following the last open season on koalas in 1927 led to the complete protection of the species.16
Now Australian koala populations face other hazards – loss of habitat, disease, bushfires, dog attacks, vehicle strikes, and perhaps most distressing, overpopulation in habitats with limited food sources and no predation, leading to starvation.17 Wildlife managers face tough decisions with regard to both conserving and managing koala populations, but the take-home message is that if Australians want to ensure the survival of their beloved koalas, they must ensure the survival of the eucalypt forests in which koalas live.18
References:
1. Roger Martin and Kathrine Handasyde. The Koala: Natural history, conservation and management. 1999. University of New South Wales Press, p. 3.
2. T. Wood. Cobbers: A personal record of a journey from Essex in England, to Australia, made in the years 1930, 1931, and 1932. Oxford University Press, London, p. 147. Quoted in: Stephen Jackson. Koala: Origins of an Icon. 2007. Allen & Unwin, Crows Nest, New South Wales, p. 47.
3. Martin and Handesyde, p. 39.
4. Jackson, p. 16.
5. Martin and Handesyde, p. 52; 6. Ibid, p. 44; 7. Ibid, p. 44-45; 8. Ibid, p.53; 9. Ibid, pp. 40-42; 10. Ibid, p. 69; 11. Ibid, p. 56, Plate 7; 12. Ibid, Plate 10.
13. Jackson, p. 36; 14. Ibid, pp. xi-xii.
15. Martin and Handesyde, pp. 21-23; 16. Ibid, p. 24.
17. Martin and Handesyde, pp. 25-27; Jackson, p. xii.
18. Jackson, p. xii.
