Tammar Wallabies at the ZooHigh on Kangaroos
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At first glance they look like roly-poly teddy bears—but with long tails and strange, fleshy noses. They can climb trees and drop more than 65 feet to the ground without being hurt. It's said that when you meet one species, Dendrolagus mbaiso, in the forest it waves its arms and whistles at you. These may sound like creatures plucked from fantasy, but in fact they are real…kangaroos.
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| A juvenile Matschie's tree kangaroo held by scientist Lisa Dabek. (TKCP) |
Tree kangaroos, that is.
Although they were discovered by scientists more than 180 years ago, surprisingly little remains known about them today—primarily because most live in the remote, inaccessible highland cloud forests of New Guinea. For millennia tree kangaroos flourished in the island's interior labyrinth of mountains. But now these extraordinary animals are on the verge of extinction because of the very predators who can also save them: humans.
Return to the Trees
Until recently, many of New Guinea's mammals were little-known. Most of what we know about tree kangaroos has been gleaned since the 1970s, and as each new species is discovered, a fascinating portrait of these animals has been slowly emerging.
Scientists think all kangaroos and their smaller cousins, wallabies, first evolved about 55 million years ago from tree-dwelling Australian marsupials that looked like possums. In time, some of these marsupials apparently found life was safer (and the food better) back up in the trees. Over millions of years they reversed the typical land-kangaroo physique, evolving shorter hind feet and longer, stronger arms, eventually becoming the marsupial equivalent of monkeys: tree kangaroos.
Australia collided with Asia about 15 million years ago, pushing up a northern mountain range that later became New Guinea. When rising seas flooded its lowlands, New Guinea became an island, permanently isolated from Australia. The wide range of habitats on its craggy landscape gave rise to an array of plants and animals, including tree kangaroos, whose evolutionary path continues to amaze scientists. "The very concept of such an animal seems ludicrous," wrote biological anthropologist Colin Groves of Australia's National University in a scientific paper in 1982. "That such a fundamentally terrestrial animal as a kangaroo should not only take to the trees, but undergo there a successful radiation into several species, seems against all common sense."
Of the 12 known species of tree kangaroo, ten are found exclusively in New Guinea, and the other two live only in northern Australia. They form two distinctive lineages: the lowland "long-footed" group, with generally smaller heads, larger size, and broad, kangaroo-like feet that indicate they may be the most archaic species; and the highly arboreal, "short-footed" line of New Guinea's highlands. Some have even lost the ability to hop.
Most of New Guinea's tree kangaroos live high in its chilly, mountain cloud forests, where vegetation is abundant and predators rare. They are the island's largest mammal—some species weigh up to 45 pounds—and apart from a few mainly terrestrial species, they spend time high in the trees resting and browsing on tender leaves, fruits, flowers, and the occasional bird's egg. To avoid predators like the New Guinea harpy eagle (Harpyopsis novaeguineae), most tree kangaroos can drop straight from the treetops to the ground without serious injury thanks to their thick, strong bones.
Until the 19th century, New Guinea's tree kangaroos were known only to local clans, whose Melanesian ancestors arrived about 45,000 years ago. Highland tribal folklore often tells of furry shape-shifters of the forest that played tricks on the disrespectful.
Protein in New Guinea was often scarce, and for most clans tree kangaroos were a staple food. In 1840 zoologist Salomon Müller, who had collected tree kangaroo specimens on western New Guinea's coast, named their genus Dendrolagus, which is Greek for tree hares—not because of their appearance, but because they tasted like succulent hare.
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| Matschie's tree kangaroo. (Jessie Cohen/NZP) |
In those days, going to New Guinea entailed a lengthy and often dangerous journey, so some Victorian naturalists "discovered" new tree kangaroo species from skins bought in Europe's fur or feather markets. In the early 20th century, the flamboyantly eccentric English aristocrat Lord Walter Rothschild hired traders to bring him specimens of several tree kangaroo species, including a reddish variety from northeastern New Guinea that he and a colleague named D. matschiei in 1907.
Because so few zoologists actually went to New Guinea, most of what they knew about tree kangaroos until recently was the color of the kangaroos' fur and the shape of their bones. When Tim Flannery, then an Australian graduate student, began compiling the first field guide to New Guinea mammals in the 1980s, he was shocked to discover how little real data were available. So, he resolved to find out for himself, and ventured into the remote wilderness of that mysterious island.
Flannery's Discoveries
Feverish with scrub typhus in 1985, Flannery was being carried to a mission hospital on the north coast of New Guinea when he noticed something unusual. In his 1996 memoir Throwim Way Leg, Flannery wrote that through his delirium, he became "intrigued by a black claw which one of my bearers was wearing on a string around his neck. When we arrived at the mission I somehow managed to buy the necklace from him." That claw turned out to be a clue to a previously undescribed species of tree kangaroo, known to the Olo people of the Torricelli Mountains as Tenkile.
Three years later Flannery, now a scientist for the Australian Museum in Sydney, returned to northern New Guinea, following Olo hunters deep into the Torricellis, looking for rumored species like Tenkile. After weeks of searching, his efforts were rewarded when hunters returned to camp carrying a strange, black tree kangaroo. As Flannery examined the animal he later dubbed D. scottae, the hunters told him that when they caught an adult male, everyone in the village knew immediately because of the Tenkile's pungent, lingering odor, which is unlike any other tree kangaroos'.
For more than a decade Flannery explored the highland forests of New Guinea, discovering some 30 new mammals. He described four new tree kangaroo species, providing some of the first insights into their biology and inspiring a new generation of scientists to seek out and protect New Guinea's mammal species from extinction.
The discovery Flannery considers his greatest occurred in 1994 on the glacier-bound Jaya Peak in far western New Guinea. Unlike independent Papua New Guinea, which covers the island's eastern half, Indonesian-ruled West Papua was at the time less explored by scientists. Camping about 10,000 feet up in one of Jaya Peak's chilly rainforests, Flannery was told stories by local Moni tribesmen about Dingiso, the little furry "men of the forest" that when confronted would sit up, whistle, and raise their paws in greeting. To Flannery this sounded like a typical kangaroo threat-display, but the Moni believed these creatures were ancestor spirits who recognized them, and they never hunted them.
This bit of unwitting conservation may have saved some of the last populations of this species, because while Dingiso were common in Moni lands, they were completely hunted out in the neighboring Dani people's territory. In fact, overhunting may be the greatest threat to all tree kangaroos in New Guinea, as villagers venture into more-remote mountain forests to feed their growing populations.
This problem was on Flannery's mind when a Dani hunter brought him that first beautiful, black-and-white specimen of Dingiso. Flannery gave the species the name mbaiso, the Moni word for "forbidden animal," hoping to deter other clans from wiping it out.
The Dani said Dingiso was rarely seen in trees, and Flannery suspectedit was largely terrestrial, yet another twist in the up-and-down evolution of these amazing marsupials. Dingiso also seemed unafraid of humans. "When the hunters find it, they offer it some choice leaves and it approaches them," Flannery wrote in Throwim Way Leg. "Then they simply slip a noose around its head and lead it away." If a large mammal like Dingiso could remain totally unknown to science for so long, Flannery noted, who knows what other new species might still lurk in New Guinea's remote forests?
Matschie's Tree Kangaroo
Lisa Dabek's first encounters with live tree kangaroos weren't in the depths of a tropical forest, but at zoos here in the U.S. In 1987, she was a graduate student specializing in marine mammals, but after studying the mothering behavior of D. matschiei with Judie Steenberg, a keeper at Seattle's Woodland Park Zoo, Dabek became so enthralled that she made tree kangaroos the focus of her career.
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| Lisa Dabek with a Matschie's tree kangaroo. (TKCP) |
Five years later, she did pioneering research on matschiei reproductive biology at the Smithsonian National Zoo's Conservation and Research Center in Front Royal, Virginia, helping curator Larry Collins design the first breeding program for what was then the largest collection of tree kangaroos in North America. It was a life-changing experience. "Our research became the bedrock of my entire career," Dabek explains. "It made everything I've done since then possible, and probably saved Matschie's tree kangaroo from extinction." Further inspiration came when she met Flannery at an Australian tree kangaroo conference in 1994. His intrepid example prompted Dabek to defy prevailing notions that studying these elusive animals would be too expensive and hazardous.
In 1996, she founded the first-ever Tree Kangaroo Conservation Program (TKCP) with support from 16 North American zoos, and launched the first field studies of D. matschiei, deep in the scientific terra incognita of Papua New Guinea's northeastern Huon Peninsula. For nearly five weeks, she and a graduate student explored the central forests of this hulking, 650-mile ridge of jagged limestone, the only place where matschiei has been found. But all she discovered were clawed tree trunks and thousands of little green tree-kangaroo droppings.
Then one day, while following some local Yupno hunters through the dense, mossy forests around the Huon's Finnisterre Mountains, Dabek's luck changed. When the hunters' dogs began barking at something high in a tree, she peered up and saw the creature the Yupno called Klapgaman: a stout, red animal with a soft pink nose and furry ears. "It looked like a big stuffed animal," Dabek recalls. "I watched that tree kangaroo for nearly an hour, and then didn't see another one for seven years. But they were worth the wait."
Now, as Director of Conservation for the Woodland Park Zoo, Dabek oversees the support of more than 30 different international endangered species projects and leads one of New Guinea's most successful conservation efforts. Like other tree kangaroos, once-abundant D. matschiei are so overhunted that they are found only in high alpine forests, the territory of the Yupno and other clans for millennia. Because of this, Dabek realized the only way to create a no-hunting zone where the species could be protected and studied was to make local clans firm partners of her project. The TKCP is negotiating an agreement with 26 clans to set aside about 312 square miles of tree kangaroo forest, creating a vast conservation area where landowners are the wildlife stewards, and poaching is punishable by law. Once approved by Papua New Guinea's government, these lands will become the island's first official conservation area.
Every year Dabek and her team hike nine hours into the rain-soaked highlands of Wasaunon, her primary field site in the protected area, and home to a flourishing array of rare, native wildlife. The scientists, led by graduate student Gabriel Porolak, often spend months 10,000 feet above sea level in these lush, mossy forests, gathering pioneering data on a local population of matschiei. They found that like most tree kangaroos, matschiei are predominantly vegetarians, getting their deep rusty color from acidic tannins in their diet. While matschiei are largely solitary animals, far-ranging males keep close track of the females in their area, which are receptive to mating for just two days every two months.
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| An adult Matschie's tree kangaroo with its young. (Jessie Cohen/NZP) |
So far, Porolak has fitted 13 Wasaunon 'roos with radiocollars, using global positioning system satellite data to figure out their natural range—vital for designing a conservation area. It's lots of long hours and tough, soggy conditions, but Dabek is in her element. "This is really intense work,"she says. "It really challenges you on so many different levels: You're hacking through the brush. You're radiotracking—and radiotracking a strong male is a real challenge—and it's all new to science!"
The Most Beautiful Kangaroo
The Olo people of the Torricelli Mountains had a legend of a forest creature called the Weiman or Weimanke, an animal with a very pale face. Exploring the Foja Mountains of western Papua in the 1980s, Pulitzer prize-winning author and scientist Jared Diamond reported glimpsing a striking, white-faced tree kangaroo, but couldn't snap a photo before it vanished. Nearly a decade later and hundreds of miles to the east, Tim Flannery was exploring Mount Sapau in the Torricellis when one of his colleagues returned to camp carrying two spectacularly colored Weiman: Their ears were rimmed in white, their shoulder fur was lustrous gold, their backs were deep burgundy, and white rings swirled down their long tails. Flannery named the species D. goodfellowi pulcherrimus—"most beautiful" in Latin—and described them as a subspecies of Goodfellow's tree kangaroo. But no one could prove this family link, because he only found two animals.
Then, in December 2005, an international team of scientists was allowed to explore the Foja Mountains, its helicopter landing in a realm of animals thought to be exceedingly rare or even extinct. Lush, wet, and cold, it was prime tree kangaroo territory, and early one morning Kristofer Helgen, the team's mammalogist and a scientist at the Smithsonian's National Museum of Natural History, awoke to his trackers excitedly showing him a large Weiman they'd caught—the first one found by scientists outside the Torricellis, and proof that Weiman weren't as endangered as they had feared. The Weiman is now classified as D. pulcherrimus and its common name is the golden-mantled tree kangaroo.
About the same time, Australian zoologist Jim Thomas was visiting the scattered villages of Sandaun Province, in the Torricelli Mountains. He and his wife Jean had run the Tenkile Conservation Alliance for two years, hoping to do for the Tenkile what Lisa Dabek had achieved for D. matschiei. Working on a shoestring budget from a tin-roofed bush house, the Thomases successfully negotiated a two-year hunting moratorium among 12 villages in Tenkile territory, encouraging locals to raise domestic rabbits for meat instead of hunting 'roos.
When he arrived in the Nunsi community village in December 2005, hunters presented Thomas with a squirming baby male D. pulcherrimus—the first living one any scientist had ever studied. Now about two, "Nunsi" is a cuddly ambassador for his species, helping the Thomases broker a Weiman hunting ban in March 2006 in eastern Sandaun where the species is thought to live. Advised by the TKCP, Thomas wants to begin radiocollaring both species, to fill in some of the scientific blanks about these elusive animals. But raising the necessary funds could take years.
It's an important fact about New Guinea's tree kangaroos: They don't give their secrets away easily. Those who want to learn must stay for the long haul, which apparently suits Jim and Jean Thomas just fine. "You could say this is a dream come true," Jim says, "but basically I just didn't give up—and when you are committed to real conservation, you can't."
—John Tidwell is a freelance journalist who lives in Silver Spring, Maryland.
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