The rainforested areas of Australia and New Guinea are home to a little known, rarely seen and largely understudied creature, the tree-kangaroo.  Kangaroos are not the first creatures that spring to mind when contemplating tree-dwelling mammals.  Most people's idea of macropods is of large, bouncy animals soaring across red-soil plains, but tree kangaroos have very successfully made their living in the canopy.  Indeed, they represent a respectable 16 species and sub-species of about 73 species of macropods, nearly 22%.

Tree-kangaroos were first discovered in 1826, when Dutch scientists on a mission to collect natural history specimens landed at Lobo, on the NW coat of New Guinea and acquired 4 live specimens of an as yet unknown mammal, with the intention of shipping them back to Europe.  Unfortunately, particularly for the tree-kangaroos collected, misfortune intervened.  Malaria struck the ship and the scientists on board fell gravely ill.  The ship's officer immediately had the animals killed and turned into a nourishing dish to aid the invalids, based on a Dutch dish called hazenpeper, or peppered hare.  This interesting side note in scientific history is how tree-kangaroos acquired their scientific name of Dendrolagos, or tree-hare (Martin, 2005).

Figure 1. Dendrolagus inustus, the grizzled tree-kangaroo.  This was the first species
of tree-kangaroo discovered by Western science.  It was also probably the
first to be eaten by Westerners.  Source: jumbhoanimal.blogspot.com

Australia possesses two of the 16 species of tree-kangaroo, Bennett's and Lumholtz's, restricted to the rainforests and vine thickets of far north Queensland.  The first discovery of this genus made in Australia was in 1872.  William Hann was commissioned by the Queensland government to explore the mineral potential of Cape York Peninsula.  Hann's Aboriginal guide, Jerry, had mentioned the existence of a tree-climbing kangaroo, a story which Hann scarcely believed.  Scratches on trees were found, however, followed by a complete skeleton.  This, the first hard evidence of tree-kangaroos in Australia, was collected by the party but subsequently lost (Martin, 2005).

Figure 2. Lithograph of Bennett's tree kangaroo by Joseph Smit, published in the
 Proceedings of the Zoological Sociey of London, 1894.  Source: Wikimedia Commons 

Tree-kangaroos are a cryptic animal, as anyone who has spent time looking for them will wearily tell you, and the latest discovery by Western science of a new species, D. mbaiso, known by locals as Dingiso, was made in 1992, in West Papua's Central Highlands, an amazing find for a relatively large mammal (Martin, 2005).   This little explored and largely inaccessible country may yet produce new species, an excitingly tantalising prospect.





                                    Table 1. Tree kangaroo taxonomy.  Adapted from Flannery et al. (1996)

Dendrolagus bennettianus		Bennett’s tree-kangaroo
Dendrolagus lumholtzi		Lumholtz’s tree-kangaroo
Dendrolagus inustus	D. i. inustus	Grizzled tree-kangaroo
	D. i. finschi	Finsch's tree-kangaroo
Dendrolagus ursinus		Vogelkopt tree-kangaroo
Dendrolagus goodfellowi	D. g. goodfellowi	Goodfellow's tree-kangaroo
	D. g. buergersi	Timboyok
	D. g. pulcherrimus	Golden-mantled tree-kangaroo
Dendrolagus matchiei		Matschie's tree-kangaroo
Dendrolagus spadix		Loland tree-kangaroo
Dendrolagus dorianus	D. d. dorianus	Doria's tree-kangaroo
	D. d. mayri	Wondiwoi tree-kangaroo
	D. d. notatus	Ifola
	D. d. stellarum	Seri's tree-kangaroo
Dendrolagus scottae		Tenkile
Dendrolagus mbaiso		Dingiso

References:

Flannery, T. F. et al. Tree Kangaroos. Port Melbourne, Vic.: Reed, 1996. Print.

Martin, R., and Simpson, S. Tree-Kangaroos Of Australia And New Guinea. Collingwood, VIC: CSIRO Pub., 2005. Print.


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