Guardian an­gels

Mada­gas­car’s moun­tain forests are haunted by one of the world’s rarest and most beau­ti­ful pri­mates, the snow-white silky sifaka.

BBC Wildlife Magazine - - Contents - By Mike Un­win Pho­to­graphs Ugo Mel­lone

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.

Mis­taken iden­tity

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.

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