Varecia variegata variegata
This visually striking species hails from the tropical forests of eastern Madagascar, where its thick fur is well suited to the wet, sometimes chilly environment of the rainforest canopy. Weighing up to nine pounds (4.1 kg), black and white ruffed lemurs are among the largest living lemurs and the largest pollinators in the world: as they feed, pollen sticks to the ruffs of fur around their faces and gets transported from tree to tree.
Female ruffed lemurs give birth to litters of infants. Unlike other lemurs whose infants cling to their bellies or backs, ruffed lemurs “park” their infants in nests while foraging. Mothers can have as many as six infants at a time, although litters of two to four are most common. Ruffed lemur families are highly vocal, and their raucous loud calls can be heard up to a half-mile away.
The black and white ruffed lemur is critically endangered in Madagascar, primarily due to hunting and habitat loss and fragmentation. Threats include slash-and-burn agriculture (tavy) and illegal logging and mining, as well as natural disasters like cyclones.
Ruffed lemurs' diets consist primarily of fruit, nectar, and pollen. As fruit-eaters, they play an important role as seed dispersers in Madagascar's rainforests: They can swallow large seeds, which pass through their guts undigested and are excreted onto the forest floor in their own packets of "fertilizer" (feces). If large seed-dispersers like ruffed lemurs disappear, these large trees could disappear too.
Ruffed lemurs are the largest pollinators in the world. When feeding on the nectar of the traveler's palm (Ravenala madagascariensis), black and white ruffed lemurs pry open the blooms and push their long, narrow muzzles deep into the nectar chamber. As they do so, pollen sticks to the ruffed fur around the lemurs' faces and gets transported from tree to tree.
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.
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.
Pictured: A member of Kizzy's group of seven black and white ruffs forages for wild autumnal berries, nuts, seeds, flowers, and leaves. Here, a group member nibbles a local favorite: Hearts-A-Burstin (Euonymus americanus). Photo by David Haring.
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 ruffed lemurs 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, in Madagscar 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.
Pictured: Ruffed lemur mother and infant. Photo by David Haring.
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 ("diameter at breast height") 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.
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, 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.
Black and white ruffed lemurs are critically endangered in Madagascar. Primary threats include habitat loss due to slash-and-burn agriculture, logging, and mining; and bushmeat hunting.
Whereas populations of wild ruffed lemurs are critically endangered, the animals thrive in captivity. 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 Species Survival Plan (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 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.
*SSPs outline the breeding plans for each species as determined by a team of experts, which selects breeding pairs of males and females based on how genetically valuable their offspring would be to the captive population. The goal of each SSP is “to ensure the sustainability of a healthy, genetically diverse, and demographically stable population for the long-term future.”
In 1997, the Duke Lemur Center, as part of a consortium of zoos and conservation groups known as the MFG (Madagascar Fauna and Flora Group), released five black and white ruffed lemurs into the Betampona Reserve in eastern Madagascar. These lemurs had been born, and had lived their entire lives, in the Natural Habitat Enclosures of the DLC.
In 1998 and 2001, two more groups of U.S.-born lemurs were released into the Reserve. All of these lemurs had some previous experience free-ranging in forested enclosures at the DLC, and the more such experience they had, the more adept they seemed to be at facing the challenges presented by the wilds of Madagascar. Of the 12 animals released, as many as six successfully bred in the wild, most likely providing a much needed infusion of fresh genetic material into the wild population. A couple of the ruffed lemurs died after less than a year (victims of fossa predation) but one, Sarph, lived for over ten years.
The benefits of the release also have spread far beyond the lemurs. Today with consistent support from the MFG, research continues on Betampona’s rich flora and fauna from a permanent research station at the edge of the forest. The station also serves as an active site for the training of Malagasy university students and provides environmental outreach and agroforestry training for villagers living around the reserve. “Perhaps the most valuable result of the restocking program is that the release project became the springboard for a much broader conservation program for Betampona,” Katz said. (See "Into the Wild: Surviving pioneer lemurs celebrate a decade in the rain forest," by Karl Bates.)
You can learn more about the project by visiting the MFG webpage dedicated to the project.
Pictured: A black and white ruffed lemur released at Betampona. Photo by Adam Britt.
A quick note about terminology: The Betampona project is sometimes referred to as a "re-introduction," but it was more accurately a reinforcement (also called a restocking) of the wild population using captive-born individuals. A re-introduction, on the other hand, is putting a species back where it once lived after there are no members of the species remaining in the area. The black and white ruffed lemur population in Betampona Reserve, although small, was still extant.
We're often asked why more lemurs aren't released into Madagascar. In addition to being extremely complicated and expensive, several criteria must be met for a release to be successful. These include:
1. "Fixing" the problems that caused the habitat to become damaged in the first place (for example, logging, mining, slash-and-burn agriculture, hunting).
2. Have such a stable, genetically diverse captive population that taking individuals out of captivity and exposing them to risk in the wild won't be detrimental to the captive population. (A stable captive population is vital, in that it functions as the species' "genetic safety net" and a reservoir against the species total extinction).
Currently, the pressures that the existing (wild) animals are under in Madagascar are too great for a re-introduction or reinforcement of species.