THE RED RUFFED LEMUR

 

The red ruffed lemur (Varecia rubra) is one of two species in the genus Varecia, the ruffed lemurs; the other is the black-and-white ruffed lemur (Varecia variegata). Like all lemurs, it is native to Madagascar. It occurs only in the rainforests of Masoala, in the northeast of the island.^[1] It is one of the largest primates of Madagascar with a body length of 53 cm, a tail length of 60 cm and a weight of 3.3–3.6 kg. Its soft, thick fur is red and black in color and sports a buff or cream colored spot at the nape, but a few are known to have a white or pink patch on the back of the limbs or digits and a ring on the base of the tail in a similar color.

 

 Physical characteristics

Red ruffed lemur in detail

Ruffed lemurs are the largest members of the family Lemuridae,^[4] with this species being the larger of the two. They weigh 3.3–3.6 kg (7.3–7.9 lb).^[5] They are about 53 cm (21 in) long, with a 60 cm (24 in) tail.^[6] Females are slightly larger than males.^[7] They have slender bodies and long legs. Red ruffed lemurs have a narrow snout with small back ears that are sometimes hidden by their long fur. They groom themselves using their toothcomb.^{[citation needed]}

As their name would suggest, they have a rust-coloured ruff and body. Their heads, stomachs, tails, feet, and the insides of their legs are black. They have a white patch on the back of their neck, and may also have white markings on their feet or mouth.^[7]

 

 

 Behavior

Red ruffed lemurs grooming each other

The red ruffed lemur is a very clean animal and spends a lot of time grooming itself and in social grooming. The lower incisors (front teeth) and the claw on the second toe of the hind foot are specially adapted for this behavior. The lower incisors grow forward in line with each other and are slightly spaced. This creates a toothcomb which can be used to groom its long, soft fur. The claw is also used for grooming.

The red ruffed lemur lives 15–20 years in the wild. In captivity, 25 years is not uncommon, and one lived to be about 33 years old. It is a diurnal animal, and most active in the morning and evening.^[8]

 

Social systems

A pair of red ruffed lemurs drinking

This primate typically lives in small, matriarchal groups of 2–16 individuals, but group sizes of up to 32 have been recorded. Its diet consists primarily of fruit, nectar, and pollen. Leaves and seeds may be eaten when fruit becomes scarce.^[6] Red ruffed lemurs will sometimes form large groups during the wet season when food is plentiful. They will all find one food source and forage together as a group. During the dry season they will often separate and find food on their own when fruits are scarce . This is unusual behavior as most other diurnal lemurs will stay together and forage in large groups even during the dry season.^[6] Field studies suggest that red ruffed lemurs, like black-and-white ruffed lemurs, may be found in monogamous pairs or in small, organized groups. Individuals out in the forest communicate through loud booming calls, which can be heard over considerable distances.^[9]

 

Breeding and reproduction

 

 Red ruffed lemurs reach sexual maturity at about two years of age, and start reproducing at about three years of age.^[4] Unlike all other diurnal primates,^[6] females keep their infants in nests 10–20 m (33–66 ft) above the forest floor, made with twigs, leaves, vines, and fur. Like all lemurs, and many Madagascan mammals, it has a fixed breeding season which takes place towards the end of the dry season (May to July). This is so the young can be born in the wet season when more food is available. Ruffed lemurs are also the only primates with litters of young, and, after a gestation period of 102 days, the female may give birth to up to six, although two or three is more typical. Newborns have fur and can see, but as they cannot move, the female leaves them in the nest until they are seven weeks old. Females can nurse up to six infants at the same time. Infant red ruffed lemurs are not as well developed at birth as other lemurs. This is not surprising because red ruffed lemurs have extremely short gestation periods. At birth, infants are not able to hold onto the mother. When she moves the infants she picks them up one by one. Mothers usually move their infants away from the nest after a week or two. When she forages she leaves her infants in a nearby tree. In the few days after she gives birth, if the mother needs to leave the nest, the father will stand guard.^[10] Weaning occurs at four months.^[7] It is estimated that 65% of young do not reach three months of age, and often die by falling from the trees.^[6]

 

Diet

 

The red ruffed lemur is mainly a fruit-eater, though it is known to eat leaves and shoots. They especially like figs.^[11]

 

Communication

 

 

The Duke Lemur Center has recorded about twelve different calls. The red ruffed lemur and Black-and-White Ruffed Lemur understand each other's calls, despite living in different parts of Madagascar. Scent marking is also an important means of communication.^[6]

 

 Conservation status

 

 The IUCN Red List states that the red ruffed lemur is critically endangered. Logging, burning of habitat, cyclones, mining, hunting, and the illegal pet trade are primary threats. They also have natural predators such as large snakes, eagles, and the fossa.^[1][12] The creation of the Masoala National Park in 1997 has helped protect this species, but many red ruffed lemurs do not live within the park's boundaries, and are still at high risk.^[6]

Recent studies show that they are critically endangered with a declining wild population. Illegal logging has increased since 2009, which has reduced the available forest habitat.^[1] Illegal logging for valuable tropic hardwoods, such as rosewood, is a particular threat, and linked to political instability.^[13] The captive population of red ruffed lemurs stands at 590 animals. The population of red ruffed lemurs is directed by a Species Survival Plan.^[13] Several of these zoos work with each other in breeding and caring for the captive population. To prevent inbreeding, wild caught animals have been introduced to the captive breeding program.

 

 

 

 

 

 

 Distribution of V. rubra^[1]

 

THE 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.^[5]
 

 

 Together with the red ruffed lemur, they are the largest extant members 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). They are arboreal, spending most of their time in the high canopy of the seasonal rainforests on the eastern side of the island. They are also diurnal, active exclusively in daylight hours. Quadrupedal locomotion is preferred in the trees and on the ground, and suspensory behavior is seen during feeding. As the most frugivorous of lemurs, the diet consists mainly of fruit, although nectar and flowers are also favored, followed by leaves and some seeds.^[6]

 
 

 

 Together with the red ruffed lemur, they are the largest extant members 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).^[5] They are arboreal, spending most of their time in the high canopy of the seasonal rainforests on the eastern side of the island. They are also diurnal, active exclusively in daylight hours. Quadrupedal locomotion is preferred in the trees and on the ground, and suspensory behavior is seen during feeding. As the most frugivorous of lemurs, the diet consists mainly of fruit, although nectar and flowers are also favored, followed by leaves and some seeds.^[6]
The black-and-white ruffed lemur has a complex social structure and is known for its loud, raucous calls.^[4] It is unusual in that it exhibits several reproductive traits typically found in small, nocturnal lemurs, such as short a gestation period, large litters and rapid maturation.^[6] In captivity, they can live up to 36 years.^[7]

 

Taxonomic classification

 

 

The black-and-white ruffed lemur is one of two species within the genus Varecia, and has three subspecies. Of the three subspecies, the white-belted black-and-white ruffed lemur (Varecia variegata subcincta) is found furthest to the north,^[8] the southern black-and-white ruffed lemur (Varecia variegata editorum) is found furthest to the south,^[9] and the black-and-white ruffed lemur (Varecia variegata variegata) has a geographic range between the other two subspecies.^[10]
 

 

Anatomy and physiology

Black and white ruffed lemur eating fruit

The black and white lemur is always both black and white, their general color patterns do not usually vary. The black-and-white ruffed lemur (V. v. variegata) abdomen, tail, hands and feet, inner limbs, forehead, face and crown are black. Pelage is white on the sides, back, hind limbs and on the hindquarters. Males and females look the same.^[11]

 

Behavior

 

 Female dominance

 

 

Black-and-white ruffed lemurs demonstrate the rare behavior of female social dominance both within and outside the context of feedings. This is also found in other ruffed lemurs as well as in ring-tailed lemurs. Aggressive interactions between males and females are usually won by the female even when they do not show aggressive behavior towards the male. Unlike other species of lemurs, black-and-white ruffed lemur females occasionally show submission and more aggression needs to be maintained in order for the female to win the interaction instead of having an undecided interaction. Male aggression does not vary among seasons.^[12]
One of the main reasons that black-and-white ruffed lemurs exhibit dominance is for feeding purpose; that is they are able to establish priority over males in feeding. Reproductive females need more access to food because of the costs of carrying and caring for offspring which is why they establish this feeding priority. Energy demands in this species are particularly high. Female dominance in feeding is maintained through demonstrating some aggressive behavior and leading the group to food in order to have first access to the food. Dominance is not thought to be established in younger females so groups lacking a mature female may not have a dominant female. When a dominant female is present, she leads the group to the food source and eats more than the rest of the group.^[13]

 

Communication

 

The black-and-white ruffed lemur demonstrates several different call types each of which last several seconds. Most lemurs of a group participate in any one chorus. These lemurs are particularly known for their loud roar/shriek choruses which have several purposes including group movement, spacing among different groups, and alarming other members of the group of predators. Unlike the calls of other species, the calls of the black-and-white ruffed lemur are not likely to be for the establishment of territory for a group. The calling behavior is participated in throughout the course of a day, not concentrated at any one point of the day; however calls are usually not heard at night.^[14]

Interspecific interactions

 

 

Black-and-white ruffed lemurs are known to form a natural hybrid zone with the Red-Ruffed Lemur. This zone may have once been very large before humans came into contact with the two subspecies. The calls of the two organisms differ in frequency and pulse rate.^[15]

juvenile

 

 

Social structure

 

 

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. 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.^[16]

 

  Threats in the wild

 


While predators may be a large threat to the black and white ruffed lemur, the principal threat to their survival comes from the inhabitants of the island. Since they are comparatively large to other species of lemurs they are hunted for their meat 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.

 

Geographic location

 

The black-and-white ruffed lemur is naturally found in the eastern Madagascar rainforest. Three subspecies reside amongst Madagascar’s rainforest; they are the Varecia variegata subcinta, Varecia variegate editorum, and the Black-and-white ruffed lemur (Varecia variegata variegata). The subspecies of the Varecia variegata variegata normally can be found inhabiting areas of the rainforest below the Anove River, and between Ambatovaky Reserve and the Zahaman National Park.

 

 Ecology

Ruffed lemurs are the most frugivorous of all the lemur species, they will and often do feed on over 80 to 132 different plant species. Studies show that most of their feeding time is spent on basic fruit which consumes around 80% of that time. The rest of which is spent mostly on nectar and various other forage. In general most male black and white ruffed lemurs will eat less than a female will during the hot dry seasons of Madagascar. Another difference between the diet of male and female ruffed lemurs is that when a female is pregnant and also lactating she will eat significantly more flowers and leaves than the male in order to supply her child and the high energy cost of reproduction. Of the general plants they eat, the most common types are Canarium (Burseracea), Cryptocarya, Ocotea, Ravensara (Lauraceae), Ficus (Moraceae), Eugenia/Syzygium (Myrtaceae), and Grewia (Tiliaceae). Studies recording ruffed lemurs in captivity and in the wild over the course of a year show that ruffed lemurs on an average spend around 28% of their time feeding, 53% resting, and the last 19% socializing and moving about.

 

Population

 

 The Varecia variegata population is on a downward trend. The general population is decreasing dramatically. Studies have shown overtime that in the last 27 years there has been an 80% decrease in individual black and white ruffed lemurs. From the Vasey studies of 2003 it was shown that the most densely populated area of black and white ruffed lemurs was Nosy Mangabe. It had around 29–43 individuals/km². Consequently came Anatanamatazo with 10–15 individuals/km², and then Manomba with.4-2.5 individuals/km².[citation needed]

 

 

 

 

 

 Distribution of Varecia variegata^[1]

 

 

 

 

 

THE BLACK AND - WHITE COLOBUSES

 

 Black-and-white colobuses (or colobi) are Old World monkeys of the genus Colobus, native to Africa. They are closely related to the red colobus monkeys of genus Piliocolobus.^[1] There are five species of this monkey, and at least eight subspecies.^[1] They are generally found in high-density forests where they forage on leaves, flowers and fruit. Social groups of colobus are diverse, varying from group to group.^[2] Resident-egalitarian and allomothering relationships have been observed among the female population.^[3] Complex behaviours have also been observed in this species, including greeting rituals^[2] and varying group sleeping patterns.^[4] Colobi play a significant role in seed dispersal.

 

 Etymology

 

The word "colobus" comes from the Greek κολοβός (kolobós, "docked", "maimed") and refers to the stump-like thumb.

 

Taxonomy

 

Behaviour and ecology

A multi-male unit of Angolan colobus in a multilevel society

Colobus habitats include primary and secondary forests, riverine forests, and wooded grasslands; they are found more in higher-density logged forests than in other primary forests. Their ruminant-like digestive systems have enabled them to occupy niches that are inaccessible to other primates: they are herbivorous, eating leaves, fruit, flowers, lichen, herbaceous vegetation and bark. Colobuses are important for seed dispersal through their sloppy eating habits, as well as through their digestive systems.

Leaf toughness influences colobus foraging efficiency. Tougher leaves correlate negatively with ingestion rate (g/min) as they are costly in terms of mastication, but positively with investment (chews/g).^[16] Individuals spend approximately 150 minutes actively feeding each day.^[16] In a montane habitat colobus are known to utilise lichen as a fallback food during periods of low food availability.^[17]

Colobuses live in territorial groups that vary in both size (3-15 individuals) and structure.^[2][18][19] It was originally believed that the structure of these groups consisted of one male and about 8 female members.^[20] However, more recent observations have shown variation in structure and the number of males within groups, with one species forming multi-male, multifemale groups in a multilevel society, and in some populations supergroups form exceeding 500 individuals.^[18][19] There appears to be a dominant male, whilst there is no clear dominance among female members.^[2] Relationships among females are considered to be resident-egalitarian, as there is low competition and aggression between them within their own groups. Juveniles are treated as a lower-rank (in regards to authority) than subadults and likewise when comparing subadults to adults.^[3] Colobuses do not display any type of seasonal breeding patterns.^[21]

As suggested by their name, adult colobi have black fur with white features. White fur surrounds their facial region and a "U" shape of long white fur runs along the sides of their body. Newborn colobi are completely white with a pink face. Cases of allomothering are documented, which means members of the troop other than the infant's biological mother care for it. Allomothering is believed to increase inclusive fitness or maternal practice for the benefit of future offspring.^[22]

 

Social behaviours

Angolan black-and-white colobus with infant.

Many members participate in a greeting ritual when they are reunited with familiar individuals, an act of reaffirming.^[2] The greeting behaviour is generally carried out by the approaching monkey and often is followed with grooming. They participate in three greeting behaviours of physical contact. This includes mounting, head mounting (grasps the shoulders) and embracing.^[2] It seems as though these behaviours do not have any relationship with mating or courting.^[2]

Adult Eastern black-and-white colobus with a juvenile

Black-and-white colobus have complex sleeping patterns. They sleep in trees near a food source, which may serve to save energy.^[4] Groups seem to regularly switch up sleeping locations (suggested due to reducing risk of parasites and placement prediction) and generally do not sleep near other groups. They also tend to sleep more tightly together on nights with great visibility.^[4] They sleep in mid- to upper sections of tall trees which allows for predator watch as well as protection from ground and aerial predators while they are asleep.^[4] Although there is no obvious preference for tree type, they have often been observed in Antiaris toxicaria.^[4]

 

Conservation

 

 They are prey for many forest predators such as leopards and chimpanzees,^{[citation needed]} and are threatened by hunting for the bushmeat trade, logging, and habitat destruction.

Individuals are more vigilant (conspecific threat) in low canopy, they also spend less time scanning when they are around familiar group members as opposed to unfamiliar.^[23] There are no clear difference in vigilance between male and females. However, there is a positive correlation between mean monthly vigilance and encounter rates.^[23] Male vigilance generally increases during mating.^[24]