Black-and-white ruffed lemur

The black-and-white ruffed lemur (Varecia variegata) is an endangered species of ruffed lemur, one of two which are endemic to the island of Madagascar. Despite having a larger range than the red ruffed lemur, it has a much smaller population that is spread out, living in lower population densities and reproductively isolated. It also has less coverage and protection in large national parks than the red ruffed lemur. Three subspecies of black-and-white ruffed lemur have been recognized since the red ruffed lemur was elevated to species status in 2001. Together with the red ruffed lemur, they are the largest extant members of the family Lemuridae, ranging in length from 100 to 120 cm (39 t...

The species inhabits the eastern rainforests of Madagascar. It occurs at low to moderate altitudes, in primary forests with tall and mature trees, and by preference deep inside contiguous blocks of vegetation, although patchy forests are made use of if necessary. The three subspecies have slightly different ranges. The white-belted black-and-white ruffed lemur is found furthest to the north, the southern black-and-white ruffed lemur is found furthest to the south, and the black-and-white ruffed lemur has a geographic range between the other two subspecies.

Madagascar

Wild black-and-white ruffed lemurs have a highly frugivorous diet, with fruit making up 92% of their overall diet. Smaller percentages of leaves, nectar, seeds, and even fungi make up the remainder. Their diet is also influenced by the seasons, with certain plant parts and fruits only ripening or becoming available during certain times of the year. Water consumption also varies throughout the year and can be influenced by diet. The number of tree species utilized by for food by the lemurs can range from 19 to 40 species depending on location. The larger part of fruit items in the diet is provided by four taxa of fruit trees: Ravensara species, Chrysophyllum boivinianum, Protorhus species, and Harungana madagascariensis.

Studies of groups of black-and-white ruffed lemurs both in captivity and in the wild have demonstrated a variety of social structures from pairs to large groups. Groups have been shown to exhibit a range of fission fusion dynamics, meaning that group size can fluctuate based on resource availability. When resources (e.g. food) are plentiful, the environment can support a larger group of lemurs, but when resources are scarce, the group may split into smaller sub-groups to survive. The sub-groups can rejoin and split as needed with environmental and social cues. Parenting in this species of lemurs is unique in that no single infant is invested in but instead, females bear litters of multiple offspring. Males also play a role in the parenting of the offspring especially in smaller groups where the certainty of paternity is high. In larger groups, the chance of a female mating with more than one male increases as does uncertainty in paternity. This tends to decrease the level of male care of offspring. Instead of clinging to the mother, offspring are placed into a nest which is guarded by both parents, described in detail below.

longest observed 39.4 years.

Both males and females reach sexual maturity between the ages of 1.5 and 3 years, although breeding is not necessarily successful during the first year of maturity. Males exhibit testicular enlargement as they mature, which gradually increases over the months leading to their breeding window. After successfully breeding with a female, the male's testicles gradually reduce to normal. When females become sexually mature and enter estrus during the breeding season, their vaginas begin to open slightly, starting with a small pink dot and line, which is easily visible because the skin around the vulva is black. The pink area gradually opens over the course of several days. Once fully opened, vaginal estrus lasts 2–3 days. During this time, there is an even smaller window of time (6–12 hours) when the female is in behavioral estrus, and breeding is only possible during this period. After breeding, the female's vulva gradually closes and remains black and closed for the remainder of the year. Gestation lasts an average of 102.5 days and typically results in a litter of 2–6 offspring that are unable to cling to their mother, as in other primates. The female builds a nest where infants remain until they can leave it on their own. For the first two weeks after birth, the female stays with the infants nearly 24 hours a day. Both males and females will guard the nest. There is evidence that related as well as unrelated females will deposit their infants in communal nests and share in parental care while other individuals forage, resulting in increased infant survival compared to single-nesting females.

The black-and-white ruffed lemur is one of two species in the genus Varecia, the other being the red ruffed lemur (V. rubra). Three subspecies are recognized: the white-belted black-and-white ruffed lemur (V. v. subcincta), the Hill's ruffed lemur, (V. v. editorum), and the black-and-white ruffed lemur (V. v. variegata, the nominate subspecies). Together with the red ruffed lemur, the species is the largest extant member of the family Lemuridae, ranging in length from 100 to 120 cm (3.3 to 3.9 ft) and weighing between 3.1 and 4.1 kg (6.8 and 9.0 lb). The black-and-white ruffed lemur is always both black and white; the general color patterns do not usually vary. Abdomen, tail, hands and feet, inner limbs, forehead, face and crown are black. The fur is white on the sides, back, hind limbs and on the hindquarters. Males and females are alike.

While predators may be a large threat to the black and white ruffed lemur, the principal threat to their survival comes from the human inhabitants of the island. Since they are comparatively large to other species of lemurs they are hunted as bushmeat by poachers and village men who are looking to feed their families. Another threat to the lemurs is the agricultural practices of the local community. The slash-and-burn method of agriculture is very devastating to the natural habitat of the black and white ruffed lemur. The black-and-white ruffed lemur is preyed upon by the Henst's goshawk (Accipiter henstii), fossa (Cryptoprocta ferox), ring-tailed mongoose (Galidia elegans) and brown-tailed mongoose (Salanoia concolor). Nesting behavior poses the greatest risks for predation, especially mammalian predators.

All three subspecies of the black-and-white ruffed lemur are classified as Critically Endangered by the IUCN. The numbers of black-and-white ruffed lemurs are on a steep downward trend, dropping 80% in the 21 years before 2020, the equivalent to three generations. The Vasey studies in 2003 indicated that Nosy Mangabe is the most densely populated area of black and white ruffed lemurs. It had around 29–43 individuals/km2. Next in decreasing order came Anatanamatazo with 10–15 individuals/km2, and then Manomba with.4-2.5 individuals/km2.

The black-and-white ruffed lemur is one of two species in the genus Varecia, the other being the red ruffed lemur (V. rubra). Three subspecies are recognized: the white-belted black-and-white ruffed lemur (V. v. subcincta), the Hill's ruffed lemur, (V. v. editorum), and the black-and-white ruffed lemur (V. v. variegata, the nominate subspecies).