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The Diademed Sifaka

Study Site: Tsinjoarivo

Tsinjoarivo's Biodiversity

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Study Species: Propithecus diadema

Sifakas (family Indriidae, genus Propithecus) are a group of lemurs found only in Madagascar and distributed throughout the island except for the high plateau. There are three major groups: the P. verreauxi group occupies the drier forests of the south, southwest and west, the P. diadema group occupies the rainforests of the east, and the monotypic P. tattersalli occupies a small range in the northeast. Foliage is usually the major component of sifaka diets, although fruits and seeds can play a major role, especially in the rainy season. In 1999, a previously unknown local variant of Propithecus diadema (known as “sadabe”) was discovered at Tsinjoarivo by S. Goodman, H. Schütz and a Duke University capture expedition led by Ken Glander. I first saw this population during a brief survey in 2000, and started long-term study at Tsinjoarivo in 2001.>

Tsinjoarivo sifakas are provisionally referred to Propithecus diadema, though certain morphological differences suggest they may be distinct.  Specifically, the sifakas at Tsinjoarivo have a smaller body mass than known P. diadema populations, and their pelage is qualitatively distinct, having a duller yellow-orange color on the limbs, much less white hair surrounding the face and ears, and (variably) black patches extending onto the ventral aspect of the forelimbs and hindlimbs. As a result of the 2001 CAMP (Conservation Action and Management Plan) meeting in Madagascar, the Tsinjoarivo sifaka variant is provisionally recognized by the IUCN as a distinct taxon, and is afforded the highest possible risk category (critically endangered).


The adult male in group CONT1

At present, no population of the Tsinjoarivo sifaka is found in any protected area. At Tsinjoarivo, sifakas live in small social groups of 2-6 individuals (excluding infants <1 year). Groups have one breeding adult male, 1-2 breeding adult females, and up to four immature offspring. Breeding is strictly seasonal, with mating occurring in December and births occurring in June/July. As with other sifakas, females are dominant over males, and it is fairly common to see females displace males at feeding sites.

Four groups were examined for the 2003 behavioral study: two in continuous forest at Vatateza (CONT1, CONT2), and two in fragments at Mahatsinjo (FRAG1, FRAG2). The four study groups were habituated during November and December 2002, and after habituation could be observed reliably at close distances. Over the years we have lost two study groups, one of which (FRAG1) was decimated by fosa (Cryptoprocta ferox) predation. We now follow nine study groups: three at Vatateza, four at Mahatsinjo, and two at an intermediate site, Ankadivory.


Three subadults resting together, group CONT1


A juvenile male resting on the ground,
group CONT2

Beginning in November 2002, we have humanely captured several study animals in collaboration with Drs. Ken Glander, Julie Pomerantz and Randy Junge, using the Pneu-dart™ system. 1-2 animals per group are given radiocollars (weight ≤ 35 g), and other animals are given colored olefin collars and metal pendants.

Capture of the study animals has allowed individual recognition for behavioral study, morphometric analyses for comparison with other sifaka populations, and the collection of blood and tissue samples for both genetic analysis and health assessments.

In CONT groups, adult males and females have similar body mass. In FRAG groups body mass is reduced, but the difference is greatest for males. This is thought to be because the social dominance of females “buffers” them from reduced food availability and/or quality.