Ruffed lemur
The ruffed lemurs of the genus Varecia are strepsirrhine primates and are the largest extant lemurs within the family Lemuridae. Like all living lemurs, they are found only on the island of Madagascar. Formerly considered to be a monotypic genus, two species are now recognized: the black-and-white ruffed lemur, with its three subspecies, and the red ruffed lemur.
Ruffed lemurs are diurnal and arboreal quadrupeds, often observed leaping through the upper canopy of the seasonal tropical rainforests in eastern Madagascar. They are also the most frugivorous of the Malagasy lemurs, and they are very sensitive to habitat disturbance. Ruffed lemurs live in multi-male/multi-female groups and have a complex and flexible social structure, described as fission-fusion. They are highly vocal and have loud, raucous calls.
Ruffed lemurs are seasonal breeders and highly unusual in their reproductive strategy. They are considered an "evolutionary enigma" in that they are the largest of the extant species in Lemuridae, yet exhibit reproductive traits more common in small, nocturnal lemurs, such as short gestation periods and relatively large average litter sizes. Ruffed lemurs also build nests for their newborns, carry them by mouth, and exhibit an absentee parental system by stashing them while they forage. Infants are altricial, although they develop relatively quickly, traveling independently in the wild after 70 days and attaining full adult size by six months.
Threatened by habitat loss and hunting, ruffed lemurs are facing extinction in the wild. However, they reproduce readily in captivity and have been gradually re-introduced into the wild since 1997. Organizations that are involved in ruffed lemur conservation include the Durrell Wildlife Conservation Trust, the Lemur Conservation Foundation, the Madagascar Fauna Group, Monkeyland Primate Sanctuary in South Africa, Wildlife Trust, and the Duke Lemur Center.
Evolutionary history
s are not known in the fossil record on Madagascar until the Pleistocene and Holocene epochs. Consequently, little is known about the evolution of ruffed lemurs, let alone the entire lemur clade, which comprises the endemic primate population of the island.Although there is still much debate about the origins of lemurs on Madagascar, it is generally accepted that a single rafting event, similar to the one that brought New World monkeys to South America, occurred around 50–80 million years ago and allowed ancestral lemurs to cross the Mozambique Channel and colonize the island, which had already split from Africa, approximately 160 million years ago. The resulting founder effect and either non-existent or inferior competition resulted in speciation as the lemur ancestors radiated out to fill open or insufficiently guarded niches. Today, the endemic primate fauna of Madagascar contains over three-quarters of the extant species of the suborder Strepsirrhini, which had been abundant throughout Laurasia and Africa during the Paleocene and Eocene epochs.
Taxonomic classification
The ruffed lemur genus, Varecia, is a member of the family Lemuridae. The extinct genus, Pachylemur most closely resembled the ruffed lemurs but died out after the arrival of humans. The genus Varecia contains two species, red ruffed lemurs and black-and-white ruffed lemurs, the latter having three subspecies.- Family Lemuridae
- * Genus Eulemur: true lemurs
- * Genus Hapalemur: lesser bamboo lemurs
- * Genus Lemur: the ring-tailed lemur
- * Genus †Pachylemur
- * Genus Varecia: ruffed lemurs
- ** Black-and-white ruffed lemur, Varecia variegata
- *** Variegated black-and-white ruffed lemur, Varecia variegata variegata
- *** Southern black-and-white ruffed lemur, Varecia variegata editorum
- *** Northern black-and-white ruffed lemur, Varecia variegata subcincta
- ** Red ruffed lemur, ''Varecia rubra''
Changes in taxonomy
The red ruffed lemur and the black-and-white ruffed lemur were formerly recognized as subspecies, Varecia variegata rubra and Varecia variegata variegata respectively. In 2001 both were elevated to species status, a decision that was later supported by genetic research. Three subspecies of black-and-white ruffed lemur, which had been published decades earlier, were also recognized as variegata, editorum, and subcincta, although studies have not been entirely conclusive.
Subfossil remains of two extinct lemur species were previously classified under the genus Varecia. Found at sites in central and southwestern Madagascar, Varecia insignis and V. jullyi were very similar to modern ruffed lemurs, but more robust and assumed to be more terrestrial, and thus more prone to predation by early human settlers. More recent studies have shown that these extinct species had a diet similar to that of modern ruffed lemurs and that they were also arboreal in nature. Enough differences were demonstrated to merit a separate genus, Pachylemur. These close relatives of ruffed lemurs are now named Pachylemur insignis and P. jullyi.
| Image | Scientific name | Common name | Distribution |
| Varecia variegata | Black-and-white ruffed lemur | eastern rainforests of Madagascar | |
| Varecia rubra | Red ruffed lemur | rainforests of Masoala, Madagascar |
Anatomy and physiology
Ruffed lemurs are the largest extant members of the family Lemuridae, with an average head-body length between and a total length from, while ranging in weight from. The thick, furry tail is longer than the body, averaging in length and is used primarily for balance while moving through the trees. Ruffed lemurs exhibit neither sexual dimorphism nor sexual dichromatism, and females have three pairs of mammary glands.Image:Varecia variegata foot with toilet-claw.jpg|thumb|left|alt=Right foot of a black-and-white ruffed lemur, showing a clear flat nail on the big toe and an arching, claw-like toilet-claw on the second toe|Foot of a ruffed lemur, showing the toilet-claw on the second toe
Ruffed lemurs are characterized by their long, canine-like muzzle, which includes a significant overbite. The face is mostly black, with furry "ruffs" running from the ears to the neck. Depending on the species, these ruffs are either white or deep reddish. Likewise, the coloration of the fluffy fur also varies by species, while the coloration pattern varies by subspecies in the black-and-white ruffed lemur. There are also intermediates in color variation between the two species.
As with all lemurs, the ruffed lemur has special adaptations for grooming, including a toilet-claw on its second toe, and a toothcomb.
Locomotion
Ruffed lemurs are considered arboreal quadrupeds, with the most common type of movement being above-branch quadrupedalism. While in the canopy leaping, vertical clinging, and suspensory behavior, are also common, while bridging, bimanual movement, and bipedalism are infrequently seen. When moving from tree to tree, ruffed lemurs will look over the shoulder while clinging, launch themselves into the air, and twist mid-air so that their ventral surface lands on the new tree or limb. Suspensory behavior is more common in ruffed lemurs than in other lemur species. When ruffed lemurs come down to the ground, they continue to move quadrupedally, running with bounding hops and the tail held high.Ecology
Being highly arboreal and the most frugivorous of the lemurs, they thrive only in primary forest with large fruiting trees, where they spend most of their time in the upper canopy. By spending the majority of their time in the crown of tall forest trees, they are relatively safe from predators such as the fossa.Ruffed lemurs are active primarily during the day, during which time they feed primarily on fruits and nectar, often adopting suspensory postures while feeding. The seeds of the fruit they eat pass through their digestive tract and are propagated throughout the rainforests in their feces, helping to ensure new plant growth and a healthy forest ecosystem. These lemurs are also significant pollinators of the traveler's tree. Without destroying the inflorescence, they lick the nectar from deep inside the flower using their long muzzles and tongues, collecting and transferring pollen on their snouts and fur from plant to plant. This relationship is thought to be a result of co-evolution.
Geographic range and habitat
Like all lemurs, this genus is found only on the island of Madagascar off the southeastern coast of Africa. Confined to the island's seasonal eastern tropical rainforests, it is uncommon to rare throughout its range, which historically ran from the Masoala Peninsula in the northeast to the Mananara River in the south. Today, the black-and-white ruffed lemur has a much larger range than the red ruffed lemur, although it is very patchy, extending from slightly northwest of Maroantsetra, on Antongil Bay, in the north down the coast to the Mananara River near Vangaindrano in the south. Additionally, a concentrated population of black-and-white ruffed lemurs, of the subspecies Varecia variegata subcincta, can also be found on the island reserve of Nosy Mangabe in Antongil Bay. It is suspected that this population was introduced to the island in the 1930s. The red ruffed lemur, on the other hand, has a very restricted range on the Masoala Peninsula.Historically, the confluence of the Vohimara and Antainambalana Rivers may have been a zone of hybridization between these two species, although no conclusive results have indicated current interbreeding. In general, the Antainambalana River appears to isolate the red ruffed lemurs from the neighboring subspecies of black-and-white ruffed lemur, V. v. subcincta. The subspecies V. v. variegata can be found further south, and V. v. editorum is the southernmost subspecies. The ranges of these two southern subspecies overlap and intermediate forms are reported to exist, although this has not been confirmed.
The rainforests in which these animals live are seasonal, with two primary seasons: the hot, wet season, and the cool, dry season. The primary habitat for both species, at any season, is in the crowns of trees, where they spend the majority of their time above ground. With the seasonal availability of resources being similar regardless of location, there is little to no difference in tree usage between species. From September through April, more fruit is available, so females prefer the lianas in the crowns of trees. Both sexes prefer the lower, major branches during the hot, rainy season. The tree crowns are predominantly used from May through August when young leaves and flowers are in abundance.