Where have all the lutungs gone? Mystery monkeys fast disappearing

Sixteen species of lutung — agile, adorable monkeys — range through the canopy of Asia’s rainforests, but all of these distant human relatives are threatened by us.

When I mentioned to some friends that I was writing a piece for Mongabay about langurs, their perplexed reactions were similar: “I thought you were an environmental journalist?” they said. “Why are you writing about long, tedious passages of fiction? Are you that into Henry James?”

When I assured them that rather than longueurs I was writing about langurs, an Old World family of monkeys, included within the lutung genus — animals facing daunting environmental challenges — I drew blank responses.

And in researching this story, I began to understand that is exactly why these animals are in trouble: For all the noble public enthusiasm regarding the preservation of the great apes — the chimpanzees, bonobos, gorillas and orangutans — these smaller versions of our fellow primates lie mostly outside our global environmental consciousness.

But as I’ve learned, these little monkeys, classified among the so-called “lesser apes”, have suffered as much from human encroachment, and are as much in need of our immediate aid, as are our larger, closer primate kin.

So, what’s a langur, or a lutung?

The taxonomy of these creatures is a bit confusing, as befits — or perhaps contributes to — their obscurity.

All Old World monkeys belong to the Family Cercopithecidae. The Subfamily Colobinae contains the langur or “leaf monkey” grouping, in which is included the Genus Trachypithecus, the lutungs. This genus in turn contains sixteen species endemic to two distinct ranges, one in south central and Southeast Asia (northeast India, southern China, Taiwan, Borneo, Thailand, Java and Bali), and the other confined to the southern tip of India and parts of Sri Lanka.

Across their diverse ranges, the lutungs share similarities: they’re lithe and slender, with long non-prehensile tails, agile feet and hands that allow them to leap from branch-to-branch in their preferred rainforest canopy habitats. And they are diurnal species, spending the daylight hours plucking leaves and fruit to satisfy their strictly herbivorous diets.

Lutungs’ wide-eyed, bare faces — hooded with lustrous hair of black, white, orange or gray — present an arsenal of facial expressions troublingly similar to our own: emoting what we would recognize as surprise, fear, pleasure and amazement.

These little monkeys live in social units that we call harems, wherein the dominant male mates with several females and the young are raised communally (for lutungs, at least, it really does take a village).

Life in the canopy has not been good to lutungs of late. Of the sixteen species, the Red List of the International Union for the Conservation of Nature (IUCN) assesses four as Vulnerable (the Javan, Nilgiri, Laotian and Capped langurs); two as Near Threatened (the Silvery lutung and Dusky leaf-monkey); seven as Endangered (François’s langur, Gee’s Golden langur, the Indochinese langur, the Hatinh langur, Phayre’s leaf-monkey, Shortridge’s langur and the Purple-faced langur); and two as Critically Endangered — the Delacour’s and White-headed langurs, are balanced on the edge of the abyss. The Tenasserim lutung has insufficient data for a conservation assessment, but as all of these species are known to be declining in numbers, some alarmingly so, it’s a safe bet that this species is doing poorly as well.

Phayre’s leaf monkey (Trachypithecus phayrei) an Endangered species of lutung found in Southeast Asia. Photo by tontantravel: Attribution-ShareAlike 2.0 Generic Phayre’s leaf monkey (Trachypithecus phayrei) an Endangered species of lutung found in Southeast Asia. Photo by tontantravel: Attribution-ShareAlike 2.0 Generic
Liz Bennett is Vice President for Species Conservation with the Wildlife Conservation Society, and one of the world’s few experts on this generally unfamiliar group of monkeys. In an interview with Mongabay, Dr. Bennett said that she “grew up on the edge of London and was always fascinated by wildlife, learning about animals from a young age by going to the London Zoo, watching David Attenborough nature programs on TV, and doing nature walks in the local forest.”

The plight of endangered species led her to study primates in the field for her doctorate from Cambridge. She focused on the ecology of Banded langurs — close relatives to Trachypithecus species — in Malaysia.

I asked Dr. Bennett the central question: what are the chances that this human generation will witness the extinction of a lutung species in the wild?

“Many genera of primates are highly vulnerable to extinction, due to their being relatively large, often conspicuous and, most importantly, having very slow reproductive rates compared to many other species,” she responded. The status of “Trachyithecus species has changed very significantly in recent years, and continues to do so. This places it high up on the genera of concern.”

Her reply was all too familiar; these arboreal animals are threatened by the usual long list of human-caused disruptions afflicting the natural world: “In all places, the species face two primary threats: loss and fragmentation of habitat, and hunting. Habitat loss is for many reasons, including expansion of industry and housing, local agriculture, and especially large-scale industrial agriculture such as oil palm [production]. Fragmentation is by roads, including logging roads. Both potentially form barriers between groups of animals, but more, provide access to hunters. Hunting is for food, pets and traditional medicines.”

“Hunting” here means criminal poaching, as IUCN Red Listed lutung species live in Asian countries that are all signatories to CITES (the Convention on International Trade of Wild Flora and Fauna), making it illegal to kill, harm or trade in endangered species within their borders.

But international environmental laws, like so many other human constructs, are subject to the whims of official corruption, bureaucratic inertia, failed enforcement, economic need, greed, and public indifference that typically result in rapidly vanishing wildlife.

Accidental rescue

So what’s being done to save the lutungs, while we still can? “Many government and non-government agencies are working to address this,” Bennett said, offering a bit of hope. “The two core types of activities are: (1) protecting habitats; and (2) enforcement of anti-hunting and trafficking laws.

Both approaches are challenging though, because, apart from a few high profile Trachypithecus species (such as the Cat Ba langur occupying a single Vietnamese island), most lutungs are not prominent on conservation agendas, especially compared to higher profile species such as orangutans or tigers.

“In some protected areas where enforcement through GIS-guided scientific patrol systems are in place (such as the Western Ghats, India; Western Forest Complex, Thailand), Trachypithecus species benefit from good protection — even if [those conservation efforts are] primarily aimed at protecting other high profile species,” said Bennett. “In other places, as far as we know, populations generally continue to decline, although in only a few sites are surveys being done to confirm their status.”

Aside from the tertiary benefits derived from the protection of more charismatic species, then, little is being done for, and little is precisely known about, lutung populations, except for the fact that they are in decline, and, in some cases, even collapsing.

Bedeviled by the pet trade

Unfortunately for lutungs, these species are ill-equipped to protect themselves from the illegal pet trade — that international network of global wildlife traffickers that tear animals from their habitats for a lifetime of bondage and exhibition. One imagines that such captivity must be particularly miserable for the young communally raised lutungs.

Dr. John Fleagle, an anthropologist and primatologist at SUNY Stony Brook, lists the reasons for the prominence of the trade in lutungs: the unusual looking monkeys are easy for traffickers to locate and capture; are attractive to buyers; while locals generally lack any incentive to report wildlife crime. Add to that the money to be made.

read more: https://news.mongabay.com/2016/11/where-have-all-the-lutungs-gone-mystery-monkeys-fast-disappearing/

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