Oct. 12, 1998 DURHAM, N.C. -- Four more captive black-and-white ruffed lemurs will begin a journey later this month back into the wilderness of their homeland in Madagascar in the second year of a project to replenish wild stocks of their species.
The release will mark the opening of another chapter in a scientific adventure that has seen both success and misfortune, as well as new insights into the complexities of returning captive lemurs to the wild. It is part of a three-year project by the international Madagascar Fauna Group (MFG) to systematically repatriate as many as 20 of the adaptable animals to their ancestral island nation.
On Oct. 27, four ruffed lemurs, Dawn, Jupiter, Tricia and Barney, will board an airplane to begin a several-day journey that will end at the 5,000-acre Betampona Natural Reserve in Madagascar. They will travel to Madagascar accompanied by veterinarian Graham Crawford of the San Francisco Zoo. After about a month of habituation in cages in the jungle, during which they adjust to local foods and climate, the lemurs will be released to join another group of captive lemurs released last year, as well as a dwindling population of wild lemurs.
The females Dawn and Jupiter have been undergoing "boot camp" at the Duke University Primate Center, living in a large fenced outdoor enclosure while they were being evaluated for suitability to release. Both animals came from the Hogle Zoo in Salt Lake City. Two other ruffed lemurs, Tricia and Barney, will come from the Wildlife Conservation Society breeding facility on St. Catherine's Island, off the coast of Georgia.
The four new animals were chosen to complement the first such lemurs ever released -- Janus, Letitia, Praesepe, Sarph and Zuben'ubi. Tricia will be released near the male Sarph, to give the pair an opportunity to breed. The females Dawn and Jupiter will be released with the male Barney in an area of the reserve where no ruffed lemurs live.
The first release of five animals in November 1997 has not been without incident, said project leader Charles Welch. In March, Letitia was killed by a "fossa," a panther-like animal that is itself endangered. And in July, Janus died from a broken neck, apparently from a fall.
"We were extremely disappointed, but both incidences came well after we had released the animals into the forest," said Welch. According to Welch, if the deaths had come early after the release, the researchers might have suspected a problem in the animals' ability to adapt to the wild.
In a promising development, the female Praesepe came into estrus and mated, said Welch. "These animals' reproductive receptivity is based on the daily photoperiod, so her reproductive receptivity means that she has already shifted her cycle from a North American to a Southern Hemisphere day length."
Unfortunately, said Welch, the newly released animals had not had time to mix with the wild lemurs, and Praesepe bred with her brother Zuben'ubi.
The scientists are still exploring the factors that would encourage the released animals to mix with the precariously small wild population, currently numbering about 30. "While there is movement between groups over time, we don't know all the answers about what triggers that movement," said Andrea Katz, Duke Primate Center's conservation coordinator and an MFG technical adviser, who is the project's field administrator. "It likely depends on the number of maturing males or females in a group, and what the pressures are for them to move out and find other mates. From what we know about ruffed lemurs' ranging and social behavior, they wouldn't just mix groups spontaneously."
According to Katz, the researchers' comparative studies of captive-release and wild animals have found that the two groups are very similar in their locomotion, range traveled, feeding, "sunbathing" to keep warm and other behaviors.
However, she said, in July and August the released lemurs appeared thinner and with poorer coats than comparable wild lemurs.
"July and August are winter months in Madagascar, the season of least fruit in the forest," said Katz. "It may be that the wild individuals have learned what other food sources are out there, such as leaves, that the released lemurs haven't yet identified."
The researchers have adjusted some of their procedures, as a result of their insights from the first release. For example, the animals in the Duke Primate Center boot camp are being fed via a wire basket that is hoisted high in the trees, to encourage them to spend more time aloft. Previously, such elevated feeding was done only after release.
"We believe that it is really important for these animals that are coming in from zoos to encourage them to move up into the trees," said Katz. "Such encouragement wasn't as necessary last year, because that group had lived in forested natural enclosures all their lives."
Black-and-white ruffed lemurs, known for the ruff of fur that frames their faces and the lush coats of black and white fur, are among Madagascar's most endangered. The ruffed lemurs at Duke are all named after heavenly bodies such as asteroids, planets, moons and constellations. They can only survive in primary tropical rainforests and are not able to adapt to cleared land or secondary forest.
Madagascar is one of the world's poorest nations and a major priority for conservationists. Its once-rich array of wildlife has been decimated by habitat destruction, and by its growing human population's need for usable land and forest products. Land surrounding the Betampona Reserve, for example, is under constant pressure from illegal logging, burning and over-farming. The problem is critical for lemurs' futures because all lemur species are native only to Madagascar.
The MFG, headquartered at the San Francisco Zoo, was formed in 1988 to coordinate conservation efforts for Malagasy animals there and abroad. The group includes 28 zoos and conservation centers from the U.S. and Europe. The MFG's activities include training Malagasy students, researchers and technicians. It also assists the government of Madagascar in preserving lemurs and other threatened species through breeding programs.
Besides the Duke Primate Center, primary collaborators in the Betampona restocking project are the San Francisco Zoo, Philadelphia Zoo, Roger Williams Park Zoo, Blank Park Zoo, Racine Zoo, Hattiesburg Zoo, Cleveland Zoo, Columbus Zoo, Tulsa Zoo, Dallas Zoo, Charles Paddock Zoo and St. Louis Zoo in the United States; and in Great Britain, the Jersey Wildlife Preservation Trust, Marwell Preservation Trust, Chester Zoo and Zoological Society of London.
Madagascar collaborators include the National Association for the Management of Protected Areas, the Malagasy Department of Water and Forests, the University of Madagascar and Parc Ivoloina.
Among the many funding sources for the project are The American Zoo and Aquarium Association, The Margot Marsh Biodiversity Foundation, The Thelma Doelger Charitable Trust and Forests of The World, as well as many individual donors. The project also was aided by the donation of the proceeds from the London premier of the John Cleese film, Fierce Creatures.
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