Varecia variegata variegata
Populations of wild ruffed lemurs are critically endangered in Madagascar, and yet the animals thrive in captivity, making this species an ideal candidate for re-introduction to the wild, assuming protected habitat is available. In fact, the first re-introduction of lemurs into protected habitat in Madagascar occurred in October, 1997 when five captive born ruffed lemurs were released into the Betampona Nature Reserve in eastern Madagascar. These lemurs had been born, and had lived their entire lives, in the Natural Habitat Enclosures of the DLC. Since then, two more groups of captive born lemurs have been reintroduced into the Reserve, one in November, 1998, and the next in January of 2001. The latter two groups also received “boot camp” training in the DLC forested enclosures before departure to Madagascar.
For more information on feeding behavior, or any aspect of behavior, of the black and white ruffed lemur, please consult the information listed under red ruffed lemurs. There is little difference in the ecology or behavior between the two species of Varecia.
The distribution of black and white ruffed lemurs at three sites at Ranomafana National Park in southeastern Madagascar is consistent with the hypothesis that this specialized frugivore is the most susceptible of the 12 sympatric lemur species found here to habitat disruption brought about by selective logging. Varecia is most abundant at the least disturbed sites and absent from the most intensively logged sites. Apparently, Varecia select large food trees of species that are preferentially logged. The current distribution of lemurs in Madagascar is highly affected by habitat destruction. It may be possible to use Varecia as an indicator to assess the degree of habitat disruption in a given area.
Ruffed lemur reproduction is highly seasonal. The animals breed in Madagascar between May and July. Most infants are born, after a 102 day gestation, in September and October. In North Carolina, breeding usually occurs in December or January with births in April or May.
Ruffed lemur females give birth to litters of up to six infants (two or three is more typical) in well-concealed, well-constructed nests 10 to 20 meters up a tree. Varecia are the only diurnal primates in the world to keep their infants in a nest. Females can nurse up to six infants simultaneously. Infant ruffs are not as well developed at birth as other species, which is not surprising given the brief gestation period.
At birth, infants are not capable of grasping the mother, so if she needs to transport them, she must pick them up and move them one at a time in her mouth. The mother generally moves her infants away from the nest after a week or two, at which point she leaves them parked in a tree while she forages nearby. Infants develop rapidly, and by three or four weeks they can attempt to follow their mother on their own. Not surprisingly, infant mortality appears to be very high for this species, with 65% of infants failing to make three months of age, due to accidental falls and related injuries.
There have been a limited number of studies of ruffed lemurs in the wild. Group size seems to vary greatly – – there have been reports of groups consisting of a monogamous pair and their offspring as well as reports of much larger groups of 8-16 individuals, containing adult animals of each sex. Whatever the size of a group, all members use a common home range and aggression is seen between neighboring groups. Females form the core of the group and defend its territory. The weakest social bonds appear to be between males.
A synopsis of behavioral studies in the wild indicates an apparent preference by ruffed lemurs to utilize large trees for their activities. Rigamonti (1993) found red ruffed lemurs rested, slept and fed in trees with an average DBH of 59.8 cm; Morland (1991) found that the black and white ruffed lemurs in her study site usually spent the night in large trees of two species with an average DBH of 61.5 and 118.1 cm and showed a slight tendency to feed in larger trees during the warm season when fruit was more plentiful. Balko’s preliminary work in three study sites at Ranamafana National Park showed V.v.variegata were more abundant in the site that had a higher density of large fruiting trees.
Ruffed lemurs also appear to prefer the upper half to upper third of the forest canopy. Morland reports that the upper canopy height in Nosy Mangabe forests averages 25 to 30m and the ruffed lemurs spent the greatest percent of their time mid-canopy. In Betampona, the upper canopy rarely exceeded 35m and the ruffed lemurs spent the majority of their time at a height between 15 to 35 m. White (1991) found that the ruffed lemur pair she observed rested, foraged, and traveled most frequently in the upper canopy at 20-25m. Ruffed lemurs showed the same preference for large trees when selecting nest sites.
Habitat & Conservation
The distribution of the black and white ruffed lemur is poorly known, especially in its northern limits. This lemur is distributed in low concentrations throughout the remnants of Madagascar’s eastern rainforest, from the Antainambalana River southward to the Mananara River. There is an introduced population on the island of Nosy Mangabe in the Bay of Antongil. Although found in ten protected areas, black and white ruffed lemurs are thought to occur in low densities in all but the Nosy Mangabe Special Reserve. The animals are very patchily distributed, and are gravely endangered due to deforestation and hunting by the local people who regard them as a great delicacy.There are numerous color variations in the black and white population throughout their range, with populations in the north tending to be darker than the whiter forms of the south. As many as four distinct color varieties have been recognized. Because so much of the animals’ habitat has been degraded, however, the original geographical distribution of the different color forms and its significance will never be fully understood. However, recent studies by the Wildlife Conservation Society and the American Museum of Natural History show no appreciable genetic differences among the different color variants of the black and white ruffed lemurs. This was important information in regard to planning for the reintroduction of captive born ruffed lemurs to the Betampona Reserve, eliminating the possibility that a different subspecies might inadvertently be introduced to the wild population.
Due to the great breeding success of captive ruffed lemurs, captive population size is currently too large and is descended from too few founders. The SSP coordinator determined years ago that captive breeding needed to be more carefully controlled, and that individual ruffed lemurs which were genetically overrepresented needed to be contracepted and fresh founder stock had to be imported from Madagascar. Hence, eight wild born, unrelated black and white ruffs, Varecia variegata variegata were imported into the United States in 1996 from a confiscated population in Madagascar which had been held at Zoo Ivoloina. After quarantine at the St. Louis Zoo, breeding pairs were sent out to various zoos across the country (Atlanta, Tulsa, Philadelphia). The DLC now houses 9 males and 4 females with two breeding groups.