The Wondiwoi Tree Kangaroo — Rediscovered After 90 Years in the Misty Forests of New Guinea

Imagine thinking a species is lost forever — vanished from the wild, known only by an old specimen in a museum. Such was the case for the Wondiwoi tree kangaroo (Dendrolagus mayri). First documented in 1928 in the Wondiwoi Mountains of West Papua, Indonesia, this arboreal marsupial then disappeared from scientific observation for nearly ninety years. In 2018, a surprising rediscovery challenged the assumption of its extinction and underscored the resilience of life in remote, difficult-to-access habitats.

In this post, we dig into the full story: its discovery, the long silence, the 2018 sighting, its biology, conservation status, and what the rediscovery teaches us about biodiversity loss and hope.

The First Discovery — Ernst Mayr’s 1928 Specimen
Why the Wondiwoi Tree Kangaroo Vanished from Records
The 2018 Rediscovery: Who, Where, How
Biology & Behavior of Dendrolagus mayri
Threats and Conservation Status
What Rediscovery Means for Conservation
How You Can Help & Why It Matters
Conclusion

1. The First Discovery — Ernst Mayr’s 1928 Specimen

The Wondiwoi tree kangaroo was first described in 1928 by evolutionary biologist Ernst Mayr, based on a single adult male specimen. It was collected in the Wondiwoi Peninsula, West Papua. (National Geographic)
That specimen was later described formally by Lord Rothschild and Guy Dollman in 1933 and illustrated in a 1936 monograph of the genus Dendrolagus. (Wikipedia)
The specimen’s habitat was a mossy montane forest at about 1600 meters above sea level. Its physical traits included a blackish undercoat frost-tipped with yellow hairs, reddish limbs and rump, and an almost white tail. Its weight was about 9.25 kg for the only known male specimen. (Smithsonian Magazine)

2. Why the Wondiwoi Tree Kangaroo Vanished from Records

Several factors contributed to its long absence from scientific verification:

Remote, difficult terrain. The Wondiwoi Mountains are rugged, clothed with dense bamboo thickets, steep slopes, and generally hard to traverse. Many local hunters and even scientists seldom venture above certain altitudes (often around 1,300–1,500 meters) where the forest becomes very thick. (National Geographic)
Sparse human presence and lack of surveys. Because of accessibility issues and lack of infrastructure, there were very few systematic biological surveys targeting this species. (National Geographic)
Misidentification. Some tree kangaroos of similar appearance (e.g. “dorianus type”) inhabit nearby regions, adding confusion. Without clear photographic or physical evidence, sightings remained anecdotal. (National Geographic)

Because of these reasons, scientists and conservationists gradually considered D. mayri either “extinct” or “critically endangered, possibly extinct.” (Re:wild)

3. The 2018 Rediscovery: Who, Where, How

The breakthrough came in July 2018, thanks to an expedition led by British amateur botanist Michael Smith. Here’s how it unfolded:

Purpose of the trip. Smith was originally trekking in the Wondiwoi Mountains in search of rare orchids and Vireya rhododendrons. He heard local stories or hints about a mysterious tree kangaroo in 2017, which inspired a more directed search in 2018. (National Geographic)
Team and location. He traveled with four Papuan porters, a local hunter, and Norman Terok, a student at the University of Papua in Manokwari. Their target zone: high-altitude montane forest (around 1,600 meters and up) in the rugged Wondiwoi range. (National Geographic)
Signs of presence. Claw marks on tree trunks, animal droppings (scat), and a “foxy” scent were found. These clues helped confirm the possibility of tree kangaroo activity well before visual confirmation. (National Geographic)
The sighting. On the final day of fieldwork, at about 30 meters above ground in the canopy, Smith spotted an animal peeking out behind leaves. He managed to photograph it — the first confirmed images of a live Wondiwoi tree kangaroo in the wild. (National Geographic)
Expert confirmation. Smith consulted several marsupial experts (e.g., Mark Eldridge from the Australian Museum; Roger Martin of James Cook University) to verify that the photos matched with the original specimen in terms of coat pattern, coloration, and other morphological features. They concluded with high confidence that it was indeed D. mayri. (National Geographic)

This discovery was not just exciting — it changed the narrative from “possibly extinct” to “critically endangered, but still surviving.” (Re:wild)

4. Biology & Behavior of Dendrolagus mayri

Although much remains unknown, researchers have pieced together several traits and habits of this cryptic marsupial:

Feature	What Is Known
Physical Appearance	Blackish base fur with yellow/silver frosted tips; reddish limbs and rump; almost white tail. Males weigh about 9.25 kg (the only specimen). (Smithsonian Magazine)
Habitat & Elevation	Mossy montane forests; elevation ~1,500-1,700m, with official type specimen collected at ~1,600m. Dense bamboo undergrowth at higher slopes. (National Geographic)
Diet	Not well documented; likely similar to other tree kangaroos: leaves, fruits, flowers. Possibly occasional ground feeding. (tenkile.com)
Behavior	Arboreal; strong forelimbs and claws for climbing; solitary; rarely seen. Makes marks on trunks, leaves droppings in the trees and ground; scent marks. (National Geographic)

Because only one animal had been scientifically observed until 2018, many aspects — lifespan, reproduction, territoriality — remain a mystery.

5. Threats and Conservation Status

Threats

Habitat Disturbance & Deforestation
Logging, mining (including mica extraction), and expansion of plantations (e.g., palm oil) threaten forest cover in New Guinea, including remote montane regions like Wondiwoi. (National Geographic)
Hunting
Even though the tree kangaroo’s high-altitude habitats are less accessible, some local hunting does occur in the lower slopes. The inaccessibility of habitat provides some protection. (National Geographic)
Small Population & Isolation
Given that D. mayri was known from only one specimen for decades, its population is almost certainly very small. Limited range and few individuals make it vulnerable to stochastic events (disease, climate change) and genetic issues. (Re:wild)
Mining Pressure
The Wondiwoi Peninsula is known to contain mineral resources (mica, etc.), and mining operations or proposals pose risks to habitat. (tenkile.com)

Conservation Status

According to the IUCN Red List, Dendrolagus mayri is classified as Critically Endangered (Possibly Extinct). (Re:wild)
Re:wild (an organization tracking lost species) included the Wondiwoi tree kangaroo in their "25 Most Wanted Lost Species" list. Its rediscovery in 2018 shifted focus toward conservation rather than presumed extinction. (Re:wild)

6. What Rediscovery Means for Conservation

The rediscovery of D. mayri offers multiple valuable lessons and opportunities:

Hope for lost species. Not all species presumed extinct are gone — in remote or undersurveyed habitats, some persist unnoticed. This underscores the importance of field work, even by non-professionals and citizen scientists. (National Geographic)
Need for habitat protection. With confirmation that D. mayri still exists, efforts to protect its habitat — especially the montane forests of the Wondiwoi range — become urgent. Protected areas or conservation zoning could help. (National Geographic)
Baseline data and scientific research. The rediscovery invites further investigation: population surveys; DNA sampling (e.g., from scat or tissue); ecological studies to understand diet, breeding, home range; threat mapping. (National Geographic)
Conservation awareness among locals and globally. This story provides an opportunity to engage local communities in conservation, raise awareness internationally, and perhaps secure funding. It also highlights that local knowledge (e.g., hunters, guides) can contribute clues even if casual or anecdotal.

7. How You Can Help & Why It Matters

Even though you may be far from West Papua, there are ways to support species like the Wondiwoi tree kangaroo and broader conservation causes:

Support nonprofits working in lost-species and habitat conservation (e.g. Re:wild, WWF, or organizations active in New Guinea).
Spread awareness. Sharing verified stories, scientific findings, and conservation news helps build public support.
Contribute to citizen science or funding drives, especially those focused on remote biodiversity.
Advocate for policy: supporting protections for high-elevation forests, sustainable mining practices, and international conservation agreements.
Respect indigenous/local community involvement. Engaging and supporting communities living near these habitats is critical — they are often the stewards of the land.

8. Conclusion

The story of the Wondiwoi tree kangaroo reminds us that disappearance isn’t always forever. After being known only from one specimen collected nearly a century ago, this elusive marsupial resurfaced in the dense, misty montane forests of the Wondiwoi Mountains in 2018. The rediscovery of Dendrolagus mayri emphasizes both the resilience of life in remote ecosystems and the urgency of preserving those ecosystems.

We still know very little about the Wondiwoi tree kangaroo — its population size, range, reproductive habits, or how best to protect it. But thanks to that single photograph and the footprints, droppings, and scratches high in the trees, scientists now have a lifeline, a chance to learn, and the possibility of securing its survival.

Call-to-Action

What do you think about stories like this — species escaping extinction, rediscovered in remote corners of Earth? Let me know in the comments below. If you found this post inspiring, share it so more people hear about Dendrolagus mayri. Want more insights into rare, endangered, or “lost” species? Follow this blog and check out our related articles on:

Rediscovered species around the world
In-depth species profiles (tree kangaroos, etc.)
Conservation efforts in New Guinea and Southeast Asia

Let’s keep the conversation going — together, we can support hope for species once thought lost.

Citations / Sources

John Pickrell. “Rare Tree Kangaroo Reappears After Vanishing for 90 Years,” National Geographic, Sept. 25, 2018. (National Geographic)
“Elusive Tree Kangaroo Spotted for First Time in 90 Years,” Smithsonian Magazine. (Smithsonian Magazine)
Re:wild. “Wondiwoi Tree Kangaroo,” Lost Species / Rediscovery summary. (Re:wild)
Tenkile Conservation Alliance, species information. (tenkile.com)
IUCN Red List entry for Dendrolagus mayri. (Wikipedia)

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Thursday, October 16, 2025

Rediscovery of the Wondiwoi Tree Kangaroo: Species “Extinct” for 90 Years Returns