Marojejy National Park, Camp 3 (2008)

Silky sifakas, despite their extreme rarity, exhibit the greatest elevational range of any sifaka in madagascar. In Marojejy and Anjanaharibe-Sud they are only found at moderately high elevations between 700m and 1875m. However, one group within the Makira Conservation Site inhabits a low elevation territory of 300m to 600m in altitude. Thus, they inhabit several types of elevation-specific habitats including primary montane rainforest, sclerophyllous forest, and even occasionally low ericoid bush at their highest elevations.

Andaparaty, Makira Conservation Site (2007)

A dark chest-stain or chest-patch distinguishes adult males from other age-sex classes. Chest-stains result from male scent-marking, i.e. rubbing the male-only sternal-gular gland against tree-trunks (see video too). In multi-male groups, one male, likely the dominant male, has the largest chest stain. Although sifakas are generally not considered sexually-dichromatic lemurs, they might be an example of a behaviorally-dependent sexually dichromatic lemur. All adult males possess chest-stains to some extent.

Marojejy National Park, Camp 2 (2008)

Like all other members of the family Indridae, silky sifakas generally travel between trees by vertical clinging and leaping. Quadrupedal walking is also routinely used. Occasionally, however, bipedal hopping (displayed in this photo) is used to travel across narrow substrates such as logs. Sometimes, bipedal hopping is used when traveling on the ground as well.

Marojejy National Park, Camp 2 (2006)

During the first few weeks of life, newborn infants are exclusively carried on the mother’s ventrum (front). After about the fourth week of life, infants will start to be carried on the mother’s back (dorsal “jockey riding”), as displayed in these photos.

Marojejy National Park, Camp 2 (2006)

Sifakas are known to engage in high rates of non-maternal infant care. all group members, including adult males, will care for infants.  Grooming is the most frequent form of allo-care, followed by playing, occasional carrying (displayed in these pictures), as well as nursing in a few remarkable instances.  The photo on the right displays an adult male (“pink face”) who spent 108 continuous minutes in affiliative contact with this 6 week infant.  The photo on the left is a mother carrying her own offspring as well as another mother’s infant.

Ankarana National Park (2008) & Marojejy National Park, Camp 2 (2001)

Fossa (left photo) are the only documented predator of silky sifakas, other than human beings.  Fossa are cathemeral (active day and night) viverrids capable of predating animals, such as sifakas, that are 90% of their body weight.  The photo on the right displays the week-old remains of a silky sifaka killed and eaten by the fossa, and represents the only naturally collected osteological remains of this species.

Marojejy National Park, Camp 2 (2007)

Silky sifakas are the only type of sifaka that exhibits extreme individual variation in partial skin pigmentation loss or leucism.  Although all infants are believed to be born with predominantly black faces, with age some individuals lose their pigmentation and exhibit pink faces to varying degrees.  The first western explorer to observe silky sifakas (Alfred Grandidier in 1871) believed that silky sifakas were an albino subspecies of diademed sifakas.  We now know that silky sifakas are not albinos.  All individuals possess some skin pigment and no photo-phobic individuals have been observed.

Marojejy National Park, Camp 2 (2007)

The trace of the silky sifaka.  Silky sifakas males gouge trees immediately prior to chest scent marking which leaves long-lasting visible marks.  In this remarkable behavior, males rub their chest gland (sternal-gular gland) directly over the gouge made in the tree trunks.  Eastern sifakas, such as silky sifakas, are the only group of primates in the world that routinely gouge trees exclusively for or predominantly for non-nutritive reasons.  Eastern sifakas do not consume bark and gouging is not associated with any foraging behavior.  See video page for gouging during overmarking.

Manantenina (Adjacent to Marojejy National Park) (2004)

Silky sifakas are hunted for food (left photo).  It is unclear how often this occurs.  It is clear that there is no local taboo or fady against lemur hunting in this region (white-fronted brown lemurs and red-Bellied lemurs also in left photo).  As in other parts of Madagascar, lemur hunting is believed to have increased over the last decade.  In some cases, local men have been hired (and provided with guns) by wealthier land-owners who desired any wild lemur meat as a delicacy for special occasions.  Lemur hunting is illegal, but tenrec hunting (right photo) is legal within certain seasons outside of protected areas.  Most local residents can seldom afford to purchase meat.

Sambava (2001), Sambava (2001), Sambava (2008)

Occasionally lemurs are kept as pets.  Like hunting, It is illegal, but seldom enforced.  Pet lemurs generally die within a short period of time.  The lemurs in the first two photos both had died when these families were revisited one year later.  The black and white ruffed lemur (far left photo) does not naturally occur in the Sambava region.  It was brought from Maroantsetra, a considerable distance.  The white-fronted brown lemur (middle photo) was one of six that were housed in a metal cage; they were likely breeding them.  The lesser bamboo lemur (far right photo) died within one week after it was removed (to be kept as a pet) from a nearby forest within a banana plantation.

Marojejy National Park, Camp 2 (2001)

The fieldsite at Camp 2 (Marojejia) when research first began in 2001. Erik’s tent.

Marojejy National Park, Camp 2 (2001); North-West Marojejy (2007)

Kitchen and dining area.

Marojejy National Park, Camp 2 (2001); (2007)

New bungalows built by ANGAP staff at Camp 1,2, and 3.

Marojejy National Park, Camp 2 (2001)

Our first silky sifaka research team. Left Photo: Nestor and Erik.  Middle photo: Seraphin, Momo, Jaozafy, Nestor.  Right Photo: Nestor and Desire without the continued assistance and close collaboration of numerous local residents none of this would have been possible.

Marojejy National Park, Camp 2 (2002 to 2003)

Our second research team.

Sambava Lycee (Highschool), (2004)

Conservation education.

Remote North-Western Marojejy (2007)

Three month diurnal and nocturnal lemur population density survey.

Near Andaparaty Along Antainambalana River, Makira Conservation Site

A new silky sifaka fieldsite develops with the assistance and collaboration of WCS.

Andaparaty, Makira Conservation Site (2007)

Lanto Andrianandrasana (left photo) leads the team for three months.

Andaparaty, Makira Conservation Site (2007)

The Rabeson family generously hosted, assisted, and permitted our team to camp on their land.  Two groups of silky sifakas live in the forested hills adjacent to their home.

Marojejy National Park, Camp 2 (2008)

Playing “Pass The Pigs” after a long day following the silkies.

Marojejy National Park, Camp 2 (2008)

Nestor and Erik….as always…..Nestor is the best silky sifaka tracker and research guide.