February 11, 2011 – Jen Noelken
Cornell University’s Erik Patel and his team endured a seven week expedition studying the rare silky sifaka lemur. Traveling to remote areas of Madagascar’s Marojejy National Park, Patel and his team surveyed 23 individual silkies in seven new groups. The latest study shows encouraging results, but researchers warn silky sifaka’s habitat continues to be threatened, leaving silkies critically endangered.
Propithecus candidus or silky sifaka, are large, white, rainforest lemurs found only in small areas of mountainous northeastern Madagascar. With silky white fur and the ability to leap as far as ten yards, natives of the area affectionately dubbed the primates “ghosts of the forest.” Seattle based wildlife photographer, Kevin Schafer says the silkies ability to leap from tree to tree makes the primate an elusive species to follow. Schafer has worked with Patel documenting the lemurs.
Silky sifakas are part of the indri family of lemurs. Silkies typically weigh between 11 and 14 pounds and measure up to three and a half feet long. Dietary habits include mature and young leaves, fruit, flowers, seeds, bark, soil, and roots. They can live in several types of altitudes from mountainous rainforest to low ericoid bush. Group size ranges from 2 to 9 individuals and include pair living and polygynandrous. Silky sifakas are listed as one of the rarest primates on earth and one of the top 25 most endangered mammals. Estimates place remaining populations of silkies as low as a few hundred. No silkies are in captivity. Research has shown captive silkies cannot survive.
Over the past few years, Patel’s team has found 31 silky sifaka groups with 131 total individuals in Marojejy National Park. The most recent survey was joined by Patel’s non-profit organization SIMPONA, which aims to protect silkies and their habitats. The survey spanned 24 square kilometers or just less than 15 miles of rough, rocky, mountainous terrain. Patel states the number is low given the area covered, but “noted that the silky sifaka has “patchy” population distribution, making it difficult to extrapolate the total population for the species.”
Marojejy National Park is located between the northeastern Madagascar towns of Andapa and Sambava. The Park stretches approximately 148,387 acres of land and protects the entire Marojejy Massif. Between 1952 and 1998, Marojejy was listed as a strict reserve, opened only to research scientist. In 1998 statues of Marojejy changed to a national park, making it open to all visitors. With “unparalleled biodiversity and stunning landscapes” the area was designated as a UNESCO (United Nations Educational, Scientific, and Cultural Organization) World Heritage Site in June 2007.
The area’s diverse low altitude rain forest to high altitude mountain scrub makes an ideal place for a wide range of plant and animal life. Marojejy is home to an estimated 275 species of ferns, 35 species of palms, 149 species of amphibians and reptiles, 118 species of birds, and 11 species of lemurs. Marojejy is also home to precious woods such as rosewood. Unfortunately, rosewood is a heavily harvested wood, which has created ecological devastation in the area.
Humans continue to be the primary threat to silky sifakas’ survival. Hunting of the primate and logging being the major causes. Patel said his last survey of the region in 2004 – 2005 and 2009 – 2010 was impacted by heavy illegal rosewood logging. Known as “tavy” in Madagascar, slash-and-burn practices on rosewood (and other woods) have proven to be a major cause of silky saifaka habitat lose. Patel’s current survey found no active rosewood logging in Marojejy National Park; a relief to all involved. Though Patel is pleased with the findings, he stressed destruction of the primate’s habitat must be stopped or time will run out on saving these beautiful animals.