Wondiwoi Tree Kangaroo
Known from one 1928 specimen. Found again in 2018 by an amateur botanist who had never seen a wild mammal discovery before
No confirmed photograph exists
Location
Wondiwoi Mountains, West Papua, Indonesia
Overview
The Wondiwoi tree kangaroo was described in 1928 from a single specimen collected by ornithologist Ernst Mayr during an expedition to the Wondiwoi Peninsula of New Guinea. For 90 years it existed only in that one museum skin — no further sightings, no photographs, no fieldwork. In 2018, Michael Smith, a retired British amateur botanist with no professional wildlife training, organised and funded his own expedition to the Wondiwoi Mountains to look for it. After days of difficult trekking through steep, high-altitude forest, he photographed a living individual. It was the first confirmed sighting of the species in 90 years, made by someone who had never previously been involved in a mammal rediscovery.
Why haven't we found it?
The Wondiwoi Mountains are steep, densely forested, and almost entirely unvisited by scientists. The single 1928 specimen was collected before modern camera technology, before helicopter access, and before systematic mammal surveys of New Guinea began in earnest. The peninsula has no road access. The fact that no professional expedition had targeted the animal in 90 years reflects how remote and difficult the terrain is, not how absent the animal was.
How it was found
- 1
Smith's 2018 photograph, reviewed by mammalogists at the Natural History Museum London, was confirmed as the Wondiwoi tree kangaroo — the first documentation since Mayr's 1928 type specimen.
- 2
The Wondiwoi Peninsula remains almost entirely intact montane forest. There are no active logging concessions and minimal settlement above 1,000 metres altitude. If the animal survived undetected for 90 years, the habitat that sustained it is largely still there.
- 3
A formal scientific expedition with camera traps and ecological survey equipment is planned for the Wondiwoi range. Population size, home range, and diet remain entirely unknown.
Things worth knowing
- 1
Tree kangaroos are the only members of the kangaroo family to have re-evolved arboreal life. Their ancestors descended from trees to become ground-dwelling kangaroos; tree kangaroos reversed that process, returning to the forest canopy over millions of years.
- 2
Ernst Mayr — who collected the 1928 type specimen — later became one of the 20th century's most influential evolutionary biologists. His New Guinea expedition was conducted before he published his landmark works on speciation. The tree kangaroo was one of hundreds of animals he documented on that trip.
- 3
Smith prepared for the 2018 expedition by studying the 90-year-old museum specimen measurements and reading every published account of tree kangaroo habitat in New Guinea. He had no prior experience with mammal field survey techniques.
- 4
New Guinea has the world's highest diversity of tree kangaroo species — 12 of the 14 known species are found there, most in isolated mountain ranges with limited overlap. The Wondiwoi Mountains are one of the most isolated ranges on the island.
- 5
The single 1928 specimen was collected at altitude in montane forest, suggesting the Wondiwoi tree kangaroo occupies a narrowly defined elevation band — limiting its total available habitat to a relatively small area of suitable forest on the peninsula.