DECKEN’S SIFAKA

Characteristics

Sifakas are known for their resilience and adaptability and often live in environments that are inhospitable to other primates—and Decken’s sifakas are one of the more extreme examples. They live in the unique northwestern Madagascar habitat called “tsingy,” limestone formation spires that have weathered over time to form razor-sharp edges and needle-like spears. Decken’s sifakas traverse these formidable obstacles with amazing grace and ease.

Leap by leap, they negotiate the complicated terrain by launching themselves with powerful hind legs from perch to perch. Small parachute-like skin folds open between their arms and body midair to ease and perhaps control their descent, a unique addition to sifaka locomotion. When they land, they use their long, heavily padded, hook-like fingers and opposable big toes to firmly grasp before calculating a next move. This imposing and difficult habitat would be too much for most animals—but Decken’s sifakas make it work!

Foods and Feeding

Details of the Decken’s sifaka diet are not known, because few studies of this species have been conducted. In general, sifakas eat a variety of leaves, flowers, fruit, buds, and tree bark that grow seasonally within their ranges. They digest their fibrous diet thoroughly in a digestive tract that, uncoiled, would stretch 14 to 15 times longer than their bodies. An enlarged caecum holds specialized bacteria that help break down the food. Some of these bacteria even break down the toxins found in several of the plants sifakas eat.

Behavior

Little is known about the lives of Decken’s sifakas in the wild, since navigating the tsingy terrain is challenging for researchers. For now, information about sifakas in general gives some insight into the more enigmatic Decken’s sifakas.

Sifakas are most active at the beginning and end of the day, when groups forage for food. Because of the unique challenges of their rocky world, Decken’s sifakas are known to descend to the ground more often than other sifaka species to reach areas of vegetation. When the sun reaches its peak, they take to the shade, where they can relax and digest. At dark, they settle themselves in trees and sleep. They perch sitting upright on a branch or cling with limbs wrapped around a branch or tree trunk. Asleep, they drop their head to their chest, cover it with their arms, and roll up their tail in a spiral between the legs.

Sifakas live in small groups, and Decken’s sifakas have been seen in groups of two to five. The group is matriarchal, run by a dominant female, and travels together to find food. Sifakas mark their territories using scent glands and keep a watchful eye out for invaders. When one is spotted, groups quickly raise the alarm and go on the defense. Group conflicts sometimes end in complete takeover by an opposing sifaka group. The name “sifaka” derives from their “tschi-faak” call, which is one of many alarm calls uses to warn each other of threats. Sifakas also communicate with body language and facial expressions. By grooming each other, group members form closer social bonds.

Habitat Use

Decken’s sifakas play a vital role in their ecosystems as seed dispersers. While the limestone spires of the tsingy don’t support much vegetation, the deep canyons and rifts between these escarpments contain pockets of life. As one of the few animals capable of navigating the tsingy landscape, Decken’s sifakas transport the seeds of the fruit they ingest between these otherwise isolated ecosystems.

Reproduction and Life Cycle

Mating season tends to be a time of significant social upheaval in sifaka groups, as subordinate males challenge for more dominant positions in their own or neighboring sifaka groups. While female sifakas remain with their natal group their whole lives, a male that has reached sexual maturity may leave his group if he finds an opportunity to improve his social rank by joining another.

Females typically give birth to a single infant, which grabs on to the mother’s belly as she moves around. At two or three months of age, the youngster moves onto the mother’s back and is weaned at about six months old. Youngsters develop the motor skills they need through play and experimentation, and by imitating adults, they learn survival and social skills.

Conservation and Threats

Decken’s sifaka is classified as Critically Endangered on the IUCN Red List of Threatened Species. Habitat loss is the principal threat faced by this species, and forests within its range have declined dramatically over the last few decades. Although taboos against killing them exist in some regions, hunting for meat does occur, and live capture for the illegal pet trade also takes place.

The good news is that Decken’s sifaka is found in several protected areas, including the Baie de Baly, Tsingy de Bemaraha, and Tsingy de Namoroka national parks. They also roam the Tsingy de Bemahara Strict Nature Reserve and special reserves in Ambohijanahavy, Bemarivo, Kasijy, and Maningoza. Much research is still needed to unlock the secrets of Decken’s sifakas. Developing methods for monitoring this elusive species will shed more light on their population trends, behaviors, and ecological roles, which will aid conservation efforts for this critically endangered primate.