The ruffed lemurs of the genus Varecia are
strepsirrhine primates and the largest extant lemurs within the
familyLemuridae. Like all living lemurs, they are found only on the island of
Madagascar. Formerly considered to be a monotypicgenus, 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 seasonaltropical
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 (~102 days) and relatively large average litter sizes
(~2–3). Ruffed lemurs also build nests for their newborns (the only primates
that do so), 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 (LCF),
the Madagascar Fauna Group (MFG), Monkeyland Primate Sanctuary in South Africa,
Wildlife Trust, and the Duke Lemur Center (DLC). Lemurs 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 (while it was joined to the Indian subcontinent), 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.
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.
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