Bennett's Tree-kangarooDendrolagus bennettianus
(de Vis, 1887)
"The relics before you, scanty as they are, seem to indicate the existence in Queensland of a species of Dendrolagus not identical with that which was found a short time ago by Dr Lumholtz..."
IF ONE SET out to reconstruct the ancestor of the living tree-kangaroos, Bennett's Tree-kangaroo would be a good place to begin, for it retains a number of characteristics that one would expect to find in such an ancestor. It possesses, as far as we know, all of the primitive characteristics in behaviour, body form and movement that characterise the long-footed group within the genus. In addition, it is the only member of the genus (with the exception of the Golden-mantled Tree-kangaroo Dendrolagus goodfellowi pulcherrimus) with contrasting colours on the shoulders and lower back. This colour pattern is common among rock-wallabies and other terrestrial kangaroos, but it is rare among tree-kangaroos. It may have been retained from a terrestrial ancestor.
Bennett's Tree-kangaroo dwells in both mountain and lowland rainforest. Occasionally, individuals are seen in sclerophyll woodland. These are usually young males which are migrating or older males which have lost their territory to a fitter rival.
It is a large species. The males, which are much larger than females, reach almost 14 kilograms in weight.
Bennett's Tree-kangaroo has a striking appearance. The black chest, belly and underside of the tail contrast with the paler back and shoulders in a reversal of the normal mammalian colour pattern. This colour reversal (belly darker than back) may provide the animal with camouflage from below. When the canopy of the tropical rainforest is viewed from below, it is seen in silhouette against a paler sky. Under these conditions, a pale animal may be more clearly visible than a dark one.
Until recently, Bennett's Tree-kangaroo remained among the least known of all tree-kangaroos. In part, this is because it inhabits a fairly small and remote region of northeast Queensland, to the south of Cooktown; and also because it is reclusive. A detailed study undertaken by Roger Martin from 1989 to the present, funded by the World Wide Fund for Nature, has rescued it from obscurity, elucidating many aspects of its biology. This study, which is reported upon extensively in this book, was completed under the most trying of circumstances.
We now know that Bennett's Tree-kangaroo subsists almost solely upon the leaves of various rainforest trees and vines. It is largely solitary and almost entirely nocturnal, spending the day hidden in a dense mass of vegetation in the rainforest canopy. Indeed, it is a highly cryptic species. It is possible for a person to be resident where it occurs at high density and yet rarely see one. I have stood under a tall tree laden with vines and epiphytes, which radio-tracking revealed was sheltering two individuals. After 20 minutes I finally made out two tails protruding from the mass of vines. Were it not for one slight movement, they would have been mistaken for vegetation.
Males are pugnacious and defend large territories which overlap those of two or three females. The territories of females do not overlap with those of other females and are smaller than the territories defended by males. Adult males will fight ferociously -- even to the point of death -- to expel intruders.
As with many other tree-kangaroos, the rate of reproduction is slow, the young spending about eight months in the pouch, then accompanying the mother for up to two years. Sexual maturity is probably reached at about two years of age for females. The age at which males reach sexual maturity is unknown.
In the past, Aborigines were major predators, and it appears that their hunting was effective enough to restrict the species to a few remote and rugged mountain summits. Since Aboriginal hunting has ceased, its range has expanded considerably. Today, large pythons and dingoes are their only significant predators. Although the total distribution of the species is small, it is relatively well protected within national parks.
page 94 - 95
Information reproduced from Tree Kangaroos: A Curious Natural History, Melbourne: Reed Books Australia.|
© Copyright by Timothy Fridtjof Flannery, Roger Martin, Alexandra Szalay. Illustrations Copyright by Peter Schouten, 1996.
HTML version produced with permission for Papuaweb, 2004.