Fast Fact Attack: Endangered Species No. 85 – The Purple-faced Langurs

Purple-faced langur, in Athurugiriya, near Colombo, Sri Lanka

Courtesy: Jeroen at Sri Lanka Blog

“Our treatment of animals will someday be considered barbarous. There cannot be perfect civilization until man realizes that the rights of every living creature are as sacred as his own”
David Starr Jordan

These poor little monkeys are now mistakenly swinging on power cables instead of vines. Needless to say, they don’t last very long! They are also getting hit by cars on roads – again, it goes without saying, they are not very familiar with traffic!  But, they have lost their own habitat due to man and are now forced to live in close proximity to the same.  

Next, conflict arises as man declares the monkeys a nuisance for stealing his crops – a common local pest, in fact.   Failing to take into account that he has stolen the home and food supply of the animals, he then sets about persecuting them.  And, just to exacerbate matters in this   ‘man versus monkey’ war, through this forced move, the purple-faced langurs have become more tolerant of human beings, and, as a result, have made themselves easy targets.

Western purple-faced langur  by Steve Garvie

There are four species of purple-faced langur in Sri Lanka, and all are endangered, one of them critically.  They have been fiercely driven out of their natural forest habitat and forced to find food within the gardens and rubber plantations of the invaders, which they now depend upon for their survival.  The food they are now  eating through necessity is far from adequate for these monkeys.  They, like several other species, have specialized stomachs which use symbiotic bacteria to aid digestion.  In their natural habitat, much of their nutrients and energy are derived from the complex carbohydrates contained in leaves.  Now, they must rely on cultivated fruits which are loaded with simple sugars and are difficult to absorb.

No two sub-species of purple-faced langurs are the same – their coats and cranial features vary. But, overall we can see a dark-brown to black colour on the body, legs and arms. The species sports pale to dark whiskers which sweep backwards.  Contrary to their name, they do not have purple faces – more of a grey-black colour.  They all have long arms and reduced thumbs.  Males can reach a body length of twenty-five inches, with a much longer tail length of thirty-three inches.  They can weigh up to twenty-one pounds. Females, as you would expect, tend to be slightly smaller.

Purple-faced langurs live for a quite a long time, and life spans of twenty-six years have been recorded as normal.Western purple-faced langur

Also known as purple-faced leaf monkeys, these primates have a one-male social system, very occasionally two, with a ratio of one male to one to seven females and assorted juveniles and infants.  The male will defend this group, or troop, aggressively against other males coming attempting to encroach.

There are also all-male groups consisting of anything between two and fourteen individuals.  These groups will forage separately in daylight and regroup at night to sleep.

The purple-faced langurs use three loud forms of communication; whoops, barks and residuals.  These sounds are used to alert others to predators, in defence of the group and its territory, attract suitable mates, and locate other members of the troop.  Adult males tend to be the loudest and most vociferous.  These vocalisations help conservationists, who have difficulty seeing the monkeys in the trees, to identify the species.

Western purple-faced langur with infantThere is little information about the breeding season of the purple-faced langurs available.  I suspect this may be because it is an all year round occurrence.  There is a gestation period of up to two hundred and ten days, after which one infant will be born, weighing just under one pound.  The infant’s coats are a contrast to their parents in that they are pale grey with a brownish tinge on the top of the head, arms, legs and chest.  The little ones start to eat solid food at about twelve weeks and will be fully weaned by eight months.

Natural Habitat
In general;  monsoon scrub, dry evergreen forests, mature secondary forest, undisturbed cloud forest, montane tropical forest and semi-deciduous forest.  Each sub-species has its own preference.
Sri Lanka
The southern lowland purple-faced langur (Trachypithecus vetulus vetulus) lives in the rainforests of southern Sri Lanka.
The western purple-faced langur (Trachypithecus vetulus nestor) inhabits the wet zone of western Sri Lanka.
The northern purple-faced langur (Trachypithecus vetulus philbricki) can be found in the north and east of Sri Lanka, in the dry zones.
And, the bear monkey, or montane purple-faced langur, (Trachypithecus vetulus monticola), occupies the mountains of central Sri Lanka.

What they eat
They are mainly folivorous, but, as needs must, will eat fruit, flowers and seeds (from gardens).
Loss of habitat is the greatest threat to these little primates. Because of this, they are simply not getting enough of the right food any more. There are various reasons for habitat loss, depending on the area the primates are located in, but, collectively the reasons are rapid urbanization, selective logging, encroachment for agriculture, and development for infrastructure and industry.  Occasionally, in the north-east, they have fallen victim to cyclones.  Hunting is also a  threat, either for the pet trade, subsistence or the bushmeat market (this is not a significant amount). Skins are used, by some, to make tribal drums. They are electrocuted by power lines and hit by cars on the roads.  Human conflict over crops and encounters with dogs are also becoming far too common.
Status: Endangered
Three sub-species of purple-faced langurs (Trachypithecus vetulus) are listed on the IUCN Red List of Threatened Species as Endangered. The sub-species western purple-faced langur (Trachypithecus vetulus nestor) is listed as Critically Endangered, and, is also classified as one of The World’s 25 Most Endangered Primates 2012-2014.  All purple-faced langur species are listed on CITES Appendix II.

Juvenile purple-faced leaf langur  kept as a petExact population numbers are unknown, but it is widely acknowledged these once highly prevalent monkeys are declining at an alarming rate.  Various agencies are working to minimise the threats to the purple-faced langurs, such as building corridors and rope bridges within protected areas.

A few southern lowland purple-faced langur (critically endangered) are known to be kept in captivity.


Fast Fact Attack: Endangered Species No. 79 – The Ka’apor Capuchin Monkey

Capuchin monkey

“If civilization is to survive, it must live on the interest, not the capital, of nature”
Ronald Wright

Endemic to Brazil, the Ka’apor Capuchin (Cebus kaapori) is a recently discovered member of the Cebidae family of monkeys. Targeted by hunters and having suffered from devastating habitat loss, the species has become one of the most threatened primates in the largest rainforest on Earth; living in a region with the highest level of deforestation and habitat degradation in the entire Brazilian Amazon. There are now very few Ka’apors left in the wild.

Capuchins Capuchin monkeys are among the most recognisable types of monkey on the planet.  These irrepressible and highly intelligent little primates have been trapped and captured for centuries, and used for man’s entertainment and amusement by organ grinders and exotic pet seekers.  Consequently, there are more Capuchin monkeys in captivity in the world than any other species.  For most, this means a life of isolation, anguish and gloom, and often they do not live long.  But, some are lucky, and happy Capuchins are known to be very talkative, incurably curious, highly intelligent and extremely mischievous.  Ka’apor Capuchins are also hunted mercilessly for bush-meat.

The Ka’apor species lacks the tuft of hair on its head which most others Capuchins have.  They have semi-prehensile tails, short fingers and opposable thumbs.  They also possess perfectly adapted large, square premolars with dense enamel to aid nut-cracking. Brown-tufted Capuchins have been observed using tools for this purpose.  Having developed an anvil system, they were able to crack open hard-shelled nuts using large rocks.  Aside from man and the apes, the Capuchins are the only other primates known to do this.

Adult coats of the Ka’apor are grey to reddish-brown on the back and outer limbs.  Heads and shoulders are creamy-white to silver-grey, withKa'apor capuchin a black triangular cap on the head, and faces are bare and pink in colour, as are the ears.  Hands and feet are blackish.  The species is sexually dimorphic and weighs an average of six and a half pounds. Adult Capuchins stand almost eighteen inches tall and have a tail which is roughly twenty inches long.

Ka’apor Capuchin monkeys are both arboreal and quadrupedal.  They can be found in the lower mid-canopy and the understorey, which they move through in on all fours using their semi-prehensile tails whilst feeding.

Communication within the species is wide and varied.  Capuchins use a whole range of vocal, olfactory and visual communications within their troops.  Social grooming is used as a form of bonding. Ka’apor capuchin monkey

Ka’apors are polygamous and occur in groups of up to fifteen individuals.  The breeding season ranges from October to February, followed by an average gestation period of one hundred and sixty days.  Females usually give birth to one baby, rarely twins, and will only birth every two to four seasons.  Infants cling to the mother’s back for the first three months.  By six months, they are becoming more independent and taking solids, and will soon be fully weaned.

The Ka’apor Capuchin was only recently elevated to species status.  It had been formerly classified as a sub-species of the wedge-capped Capuchin.

The Ka’apor Capuchin monkey is named after the Urubu-Ka’apor Indians, who live in the region where the monkey was first discovered.

The Ka’apor Capuchin, as with other species of Capuchin, is widely used in laboratory research.

Lowland Amazonian high forest
The Brazilian states of Pará and Maranhão.
What they eat
Fruits, seeds and arthropods, frogs, nestlings and even small mammals;  supplemented by stems, flowers and leaves.
Habitat loss due to logging, forest clearance for cattle ranching, and industrial agriculture, and extensive hunting for food.  The Guajá, or Awá, Indians in Maranhão, who hunt all primate species within their reserve (and, whose land and lives have also been destroyed by illegal logging) are known to keep orphaned Capuchin and other primates as pets.  These small monkeys are also collected for the international illegal pet trade.
Status: Endangered
The Ka’apor capuchin (Cebus kaapori) is listed on the IUCN Red List of Threatened Species as Endangered.  It is also protected under Cites Appendix 1 and listed on The World’s 25 Most Endangered Primates 2012-2014.  Ka’apors are located in the protected area of the Gurupi Biological Reserve in the State of Maranhão , which was created in 1988.  More than half of the reserve’s forest has since been lost due to selective logging. This was particularly prejudicial to the species as trees which provided the fruit Ka’apors favoured, and which made up most of their diet, were lost.   The IUCN has documented  a drastic decline in numbers of at least 80% over the past three generations. 

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Fast Fact Attack: Endangered Species No. 62 – Blue-eyed Black Lemur

Blue-eyed black lemur in tree

Photographer: Emily Payne / Daily Mail

This little primate, as are  many others, is losing his battle against organised crime. Adopting a  ‘grab it before it all goes’  policy, organised crime is now responsible for up to 90% of tropical deforestation through illegal logging.  And, at an estimated $30 to $100 billion per year, you can see the attraction for the less scrupulous members of the planet.  

Unchecked, which is what they are at the moment, these crime lords are continuing to rape the planet at the expense of wildlife, the environment and indigenous peoples. Although the United Nations Environment Program released this alarming report in September, 2012, this situation has not changed.

You may wonder why so many lemurs are featured here on this page.  The reason being; they are the world’s most endangered primates, with over 91% of species listed on the IUCN Red List as vulnerable to extinct  (twenty-three of those extant are critically endangered).  Shocking statistics!

Blue-eyed lemurs are sexually dichromatic; females are orange-brown and males are black.  The blue-eyed black lemur, also known as the Sclater’s lemur,  **  is considered a true lemur.  The blue-eyed black lemur may be the only primate  (other than humans)  to have blue eyes – an extremely rare occurrence amongst primates.  This is also what differentiates them from black lemurs.

Black lemurs have brown eyes and blue-eyed blacks, as the name suggests, have deep blue eyes.  Black lemurs are known to breed with blue-eyed black lemurs, where their habitat overlaps, but any offspring resulting from these liaisons will only ever have brown eyes.

A medium-sized blue-eyed black lemur can weigh about five and a half pounds.  They can reach an average body length of seventeen to eighteen inches, with a non-prehensile tail length of over twenty-four inches.   They have strong, human-like hands, equipped with rubbery textured skin on the palms, to aid gripping of branches.

Practised climbers, they can cover long distances by leaping through the trees using their long non-prehensile tails as a balancing tool.  Tails which are often carried high in the air as the animals moves.  On the ground, they move in a quadrupedal manner.   They manage to escape danger from humans and natural predators by suddenly dropping from the trees, hurtling through scrub to another tree, and hurriedly climbing out of sight.

The species live together in groups of two to fifteen individuals.  Leadership falls to the females in the group.   Communications between the primates consists of vocalisations, body language, facial expressions and scent marking.  Vocalisations are made up of clicking, barking, grunting and chirping, and males have been heard making a loud ‘scree’ noise when threatened.   This species has also been noted to be highly aggressive within the group.  Fights often break out during the breeding and birthing seasons.

The breeding season occurs from April to June.  Females give birth from August to October, following a gestation period of one hundred and twenty-six days.  Either twins or a single baby will be born.  Neither case is unusual. T he babies will average seventy-five grams in weight.  Both sexes are born with the same brown to black colouration  (males will begin to turn black five or six weeks after birth).

Juveniles are the first to be allowed near the infants.  The father is next in line and finally the other females in the group.  Infants cling to their mothers for the first three weeks of their lives.  After which they will make short trips out to see what is going on around them, but never straying far from the safety of mother.  At the same time they begin to experiment with solids.  The infant won’t be weaned, however, until five or six months of age.

** These beautiful lemurs are named after Philip Sclater, who during the 1800s was secretary of the London Zoological Society.

Primary and secondary sub-tropical moist forests and dry forests.  They can also be found on citrus, coffee and timber plantations.
What they eat
Mostly fruit, pollen and nectar.  They will also eat leaves, seeds, berries and the occasional insect when food is scarce during the dry season.
Habitat loss  (more than 80% in 20-25 years)  due to ongoing slash-and-burn agriculture, selective logging and uncontrolled forest fires.   They are sometimes killed as crop pests. The species is also hunted and trapped for food by the Tsimihety people, a Malagasy ethnic group.  Blue-eyed black lemurs are also captured for the illegal fur, meat and pet trade, and zoos.  Occasionally, they are kept locally as pets.
Status: Critically Endangered
The blue-eyed black lemur  (Eulemur flavifrons)  is listed on the  IUCN Red List of Threatened Species as Critically Endangered.  It is also protected under Appendix I of CITES  and recognised as one of  “The World’s 25 Most Endangered Primates”.  As few as one thousand individuals are thought to exist in the wild, though precise numbers are not available.  In 2012, twenty-nine individuals were recorded as living in zoos.

Crucial work is being carried out by various international agencies and organisations to conserve this species.  Captive breeding programmes are in place around the world, as are various in situ projects concerning local awareness.  Reforestation projects are also currently active.  Although the blue-eyed black lemur and its habitat are protected in parts, poaching and deforestation continue to escalate.  These are serious law enforcement issues which needs to be addressed with some vigour.   

There is further hope for the future of the blue-eyed black lemur, in the form of the very dedicated Duke Lemur Center, Duke University, located in Durham, North Carolina, USA. To see some of their incredible work, click on the ink.  

“When I hear of the destruction of a species, I feel just as if all the works of some great writer have perished”
Theodore Roosevelt

Fast Fact Attack: Endangered Species No. 34 – Tonkin snub-nosed monkey

Tonkin snub-nosed monkey

Photo: Tilo Nadler

The elusive Tonkin snub-nosed monkey was believed to be extinct until 1989 when a small population was found in Na Hang District in Tuyen Quang Province of Vietnam.  Later, in 2002, Fauna and Flora International discovered a further population in Ha Giang Province.

This delightful monkey is diurnal and almost exclusively arboreal; but has been known to occasionally take to the forest floor.  Sightings of these enigmatic creatures has been rare, so information is sketchy.

The basic social unit is known to be a one-male to several females ratio along with  some young . Other males form all-male groups.  Unfortunately, when groups are approached by humans they tend not to run away, which makes them easy targets for hunters.  Though the meat is considered “bad tasting” it does not stop them being killed and consumed.  They do, however, have a range of alarm and other calls, from the soft “huu chhhk” and “hoo”, to the rapid-fire “chit”, so others are warned of impending danger.

Tonkin snub-nosed monkeys are the largest of Vietnam’s primate population and have black hands and feet; black back fur and black outer sides of limbs.  The inner side of the limbs tends to be a creamy colour along with backs of legs, face and elbows.  They also have adorable, also human, pink lips and stunning blue-rimmed eyes.

Tropical evergreen forests containing steep karst limestone hills and mountains
Northern Vietnam
What they eat
Leaf stems and young leaves, unripe fruits, flowers and seeds
Aggressive  deforestation; illegal logging, cultivation for domestic use, collection of fuel-wood, the gathering of other forest products,  grazing of domestic cattle and intensive hunting.
Status: Critically Endangered
The Tonkin snub-nosed monkey (Rhinopithecus avunculus) is listed by the International Union for Conservation of Nature as Critically Endangered on their IUCN Red List. The species is also listed on The World’s 25 Most Endangered Primates – 2006 to 2008. **   It is thought there are less than 200 Tonkin snub-nosed monkeys left on the planet.   Various agencies are working to rectify the issue of habitat destruction and hunting in Khau Ca is controlled. Not so in Quan Ba, where it still poses a threat despite Tonkin snub-nosed monkeys being protected under CITES Appendix I and Group IB Decree 32/2006 of the Vietnamese law.  Whatever the conservation tactics, at the moment the future of this unusual primate still hangs very much in the balance. 

** Titled “Primates in Peril: The World’s 25 Most Endangered Primates–2006–2008”, the report compiled by 60 experts from 21 countries warns that failure to respond to the mounting threats now exacerbated by climate change will bring the first primate extinctions in more than a century. Overall, 114 of the world’s 394 primate species are classified as threatened with extinction on the IUCN Red List. [1]

“A true conservationist is a man who knows that the world is not given by his fathers but borrowed from his children”
John James Audubon