Madagascar’s mountain forests are haunted by one of the world’s rarest and most beautiful primates, the snow-white silky sifaka.
Snow-white silky sifakas haunt Madagascar’s mountain forests and can be difficult to track down
When the dawn mist lifts from the sacred slopes of Mount Marojejy, movement catches your eye: a flash of startling white travelling at speed through the dense forest canopy. It flits in and out of view like a wraith and only when it comes to a halt, framed in a gap, can you bring binoculars to bear. There’s no mistaking those long, slender limbs and pure white coat: it’s a simpona, or – to scientists – a silky sifaka. The rising sun illuminates the animal with a radiance that feels ethereal. No wonder locals know it as the ‘angel of the forest’.
It’s not always so easy to spot, however, especially when you’re craning up from the steep forest floor. “I was always hoping for cloudy skies,” admits photographer Ugo Mellone, who captured the rare images on these pages. “The animals are so white that an untrained eye can easily overlook them against the sky holes in the canopy.”
It doesn’t help that the silky sifaka’s home comprises some of the most challenging terrain on Madagascar: the Marojejy Massif, in the island’s north-east, rears to a height of 2,132m and its steep slopes are cloaked in dense forest. For years, this elusive animal and its hidden world remained shrouded in mystery, even to the few
For years, this elusive animal and its hidden world remained shrouded in mystery.
scientists who ventured there. “It was like being transported to a different world,” says Patricia Wright, conservation biologist at Stonybrook University.
It was not until this century that the silky sifaka gained proper recognition. First described to western science in 1871 by French zoologist Alfred Grandidier, it was initially classified as a white race of the diademed sifaka, Propithecus diadema. Indeed, by 1931 all Madagascar’s sifakas were thought to be races of either Verreaux’s sifaka or the diademed sifaka.
During a 2004–07 study, however, researchers noted key distinctions between the silky sifaka and other races of diademed sifaka. Molecular studies backed these up, and when the second edition of Lemurs of Madagascar (Mittermeier et al) was published, the silky received full species status, deriving its species name candidus from the Latin word for white.
Today, zoologists recognise nine species of sifaka. The name comes from the group’s explosive ‘shee-fak!’ alarm calls, and the genus as a whole is noted for its acrobatic upright leaping through the canopy and, on occasion, across terra firma. The silky sifaka is one of the largest, weighing 5–6.5kg and measuring some 48–54cm in head-body length, with a tail roughly the same again. In the field, the almost pure white of its luxuriant coat marks it out immediately from other lemurs, and is relieved only by its darker face, which becomes pinker as the animal loses pigmentation with age.
Finding silky sifakas means an early start, slogging up the tangled, muddy trails before dawn. The lemurs awake in their sleeping trees from about 5.30am, and reaffirm bonds with low contact calls while tucking into their first snack of the day. This is when
the trackers aim to locate a troop, allowing them to keep tabs on the lemurs as they set out for the day’s feeding.
In Marojejy, silky sifakas occupy a home range of some 34–47ha. Each day is spent criss-crossing this territory in search of food, covering around 700m in 24 hours and up to 500m in altitude. Using powerful back legs to bound through the canopy at speeds of up to 30kph, they can make rapid progress. But the pace is generally leisurely, stopping whenever they find productive feeding grounds. On average, some 44 per cent of the day is spent resting and 25 per cent feeding, with the rest spent in social behaviour. Social networks Research at Marojejy has found that troops vary in size from two to nine individuals, and in composition from a single pair to a mixed male-and-female group or a single male with several females. Though permanent dominance hierarchies are not known, females may take priority over males when feeding. Most interactions are gentle, with much social grooming and playful antics among younger members.
Silky sifakas are highly vocal lemurs. Researchers have identified seven different calls, which include low hums to keep in contact while foraging, a bird-like twittering to signal submission during conflict and a high repeated ‘where are you?’ howl when
Silky sifakas have a rich olfactory language, using scent to get their message across, like many lemurs.
lost. The usual alarm call in response to danger is an explosive, sneeze-like ‘zzuss’, but the appearance of a large bird overhead may also prompt a deeper, monkey-like chattering – suggesting that the species has an inherited fear of raptors, even though the Madagascar buzzards pose no real threat.
Like many lemurs, silky sifakas also have a rich olfactory language, using scent to get their message across. Males are especially industrious, and during the breeding season can be distinguished from females by the brown stains on their chest left by rubbing their sternal gular gland against tree trunks. They will also constantly check female scent markings, often overlaying them with their own scent. Strategic trees, known as totem trees, become saturated in this pungent perfume and are also often visibly scarred by males, who gouge the bark with their front ‘toothcomb’ prior to scent-marking.
There’s a good reason for males’ zealous monitoring of females’ receptiveness: mating takes place on just one day of the year, during the December– January rainy season, so they can’t afford to miss out. Females give birth some six months later and generally bear a single infant once every two years. The youngster clings to its mother’s chest for the first four weeks then rides on her back as it begins to explore the world more widely. Other troop members join in with childcare, playing, grooming, carrying and occasionally even nursing an infant that isn’t their own – a practice common to all sifakas. Upon reaching sexual maturity, at two to three years, they disperse to find new troops.
Head for heights
Mount Marojejy provides ideal habitat for silky sifakas. These are essentially animals of montane rainforest, typically found at 700–1,875m – higher than most other lemurs. In undisturbed habitat, they thrive. With a diet comprising over 76 plant species, from which they glean leaves, seeds, fruit and flowers, they’re seldom short of food, and in the treetops face few natural threats other than the fossa, a civetlike, arboreal carnivore endemic to
Madagascar but which is now also extremely rare. Indeed, the sifakas seldom descend to the ground other than for occasional mouthfuls of soil to supplement their green diet with important mineral salts.
Sadly, ideal habitat is in short supply. Madagascar has lost some 80 per cent of its native forest over the last century. Today, silky sifakas are confined to a narrow forest strip in the north-east, with the bulk of the population found in Marojejy National Park and Anjanaharibe-Sud Special Reserve. A few groups also survive in nearby Makira Forest Protected Area and in a few adjacent unprotected forest fragments.
The IUCN lists the species as Critically Endangered – it is one of the world’s 25 most endangered primates. Researchers believe there are likely to be no more than 250 mature individuals in the wild today – and there are none in captivity.
Habitat loss remains the chief threat to the silky sifaka. Even protected areas, including Marojejy National Park, which covers some 55,000ha, remain at risk of deforestation. Furthermore, there are no local taboos (known as fady) that prohibit the eating of this species – unlike with, say, the golden-crowned sifaka – so individuals are also vulnerable to the bushmeat trade.
Making new connections
But hope is not lost. With Marojejy now part of the Rainforests of Atsinanana World Heritage Site, the silky sifaka has become a flagship species for the area. While research continues, with radio-collared individuals revealing ever more about the species’ movements and behaviour, conservation groups are working with government to expand and safeguard existing reserves, and to link the sifaka’s few remaining retreats, by using protected forest corridors.
Most important, the message is now reaching local people. Conservationists within the community are boosting knowledge of silky sifakas. And now, with several habituated troops, they can even take schoolchildren into the reserve to see the sifakas for themselves. Such encounters build a sense of pride and connection and this thrill also extends to visitors, who are able to stay at a local lodge and hire an expert guide to enjoy their own sightings.
With ecotourism comes employment. And, for local people who have revered Marojejy’s forests for generations, this demonstrates that when it comes to creating livelihoods and preserving the sacred mountain, silky sifakas might just turn out to be guardian angels.
MIKE UNWIN writes about wildlife and travel and counts Madagascar among his most exciting destinations.
As one of the world’s 25 most endangered primates, silky sifakas are facing loss of habitat through deforestation. Today, there are thought to be no more than 250 mature individuals.
Left to right: a sociable species; females bear one infant every two years; males scent mark by rubbing against trees, staining their chests brown.
Clockwise from top left: pigmentation is lost with age, with faces becoming pinker; these notso-fussy eaters take their pick of over 76 plant species; few threats are encountered in the treetrops, apart from the fossa; some 80 per cent of native forest has been lost over the last century and is at further risk of deforestation.