Sunda Loris
Encyclopedia
The Sunda slow loris or greater slow loris is a strepsirrhine
primate
and a species
of slow loris
native to Indonesia
, western Malaysia, southern Thailand
and Singapore
. It measures 27 to 38 cm (10.6 to 15 in) from head to tail and weighs between 599 and 685 g (21.1 and 24.2 oz). Like other slow lorises, it has a wet nose (rhinarium
), a round head, small ears hidden in thick fur, a flat face, large eyes, small ears and a vestigial tail.
The Sunda slow loris is nocturnal and arboreal
, typically occurring in evergreen forest
s. It prefers rainforests with continuous dense canopies and has an extremely low metabolic rate compared to other mammals of its size. Its diet consists of sap
, floral nectar, fruit and arthropods. It will feed on exudates such as gum
and sap by licking wounds in trees. The species is generally solitary; one study showed only 8% of its active time was spent near other individuals. Social behavior makes up a very small part of the activity budget, though it has monogamous mating system with the offspring living with the parents. It sleeps during the day, rolled up in a ball in hidden parts of trees above the ground, often on branches, twigs, palm fronds, or liana
s. The species is polyoestrous
, usually giving birth to a single offspring after a gestation period
of 192 days. The young disperses between 16 and 27 months, generally when it is sexually mature
.
The species is listed as "Vulnerable
" on the IUCN Red List
. It is threatened with extinction due to a growing demand in the exotic pet
trade, and has become one of the most abundant primate species on sale at Indonesian pet markets. Its teeth are often pulled out before being sold as pets which can result in infection and/or death, this process makes reintroduction to the wild impossible. It also suffers from habitat loss
, which has been severe in the areas in which it is found.
, Sunda slow loris, refers to the Sunda Islands
, a group of islands in the western part of the Malay archipelago where it is found. Another common name for the species is the Greater Slow Loris. The specific name, coucang, derives from kukang, its common name in Indonesia
. It is commonly known as malu-malu, meaning "shy" in Indonesian
, and also as bukang or Kalamasan. It is sometimes called Kuskus, because local people do not distinguish between the slow loris and Cuscus
, a group of Australasian possum
s. In Malaysia they are sometimes known as kongkang or kera duku; kera is Malay for monkey while duku is the fruit-bearing tree, Lansium domesticum
. In Thailand, it is called ling lom (ลิงลม), which translates as "wind monkey".
in 1785 by the Dutch physician and naturalist Pieter Boddaert
under the name Tardigradus coucang. However, its discovery dates to 1770, when the Dutchman Arnout Vosmaer (1720–1799) described a specimen of it as a type of sloth
. Vosmaer gave it the French name "le paresseuz pentadactyle du Bengale" ("the five-fingered sloth of Bengal"), but Boddaert later argued that it was more closely aligned with the lorises of Ceylon
(now Sri Lanka) and Bengal.
Between 1800 and 1907, several other slow loris species were described, but in 1952 the primatologist William Charles Osman Hill
consolidated all the slow lorises in one species
, N. coucang, in his influential book Primates: Comparative Anatomy and Taxonomy. In 1971 Colin Groves
recognized the pygmy slow loris
(N. pygmaeus) as a separate species, and divided N. coucang into four subspecies
, while in 2001 Groves opined there were three species (N. coucang, N. pygmaeus, and N. bengalensis), and that N. coucang had three subspecies (Nycticebus coucang coucang, N. c. menagensis, and N. c. javanicus). These subspecies were promoted in 2010 to species status—the Javan slow loris
(N. javanicus) and Bornean slow loris
(N. menagensis)—leaving the Sunda slow loris without subspecies. Species differentiation was based largely on differences in morphology, such as size, fur color, and head markings.
When Étienne Geoffroy Saint-Hilaire
defined the genus Nycticebus in 1812, he made the Sunda slow loris the type species
. This was questioned in 1921 by British zoologist
Oldfield Thomas
, who noted that there was some confusion over the specimen used as the type specimen. Instead, he suggested that the type specimen was actually the Bengal slow loris
(N. bengalensis). There was also some confusion during the 1800s when Boddaert's Tardigradus coucang was mistaken for Carl Linnaeus' Lemur tardigradus, which was described in the 10th edition of Systema Naturæ
(1758) and referred to a slender loris. However, this was clarified in 1902 by mammalogist
s Witmer Stone
and James A. G. Rehn.
The species has 50 chromosomes (2n=50), and it genome size
is 3.58 pg. Of its chromosomes, 22 are metacentric
, 26 are submetacentric
, and none are acrocentric
. Its X chromosome
is submetacentric, and its Y chromosome
is metacentric.
To help clarify species and subspecies boundaries, and to establish whether morphology
-based classifications were consistent with evolutionary relationships, the phylogenetic relationships within the genus Nycticebus have been investigated using DNA sequences derived from the mitochondrial
markers D-loop
and cytochrome b
. Although most of the recognized lineages of Nycticebus (including the pygmy slow loris (N. pygmaeus), Bornean slow loris (N. menagensis) and the Javan slow loris (N. javanicus)) were shown to be genetically distinct, the analysis suggested that DNA sequences from some individuals of Sunda slow loris (N. coucang) and Bengal slow loris (N. bengalensis) apparently share a closer evolutionary relationship with each other than with members of their own species. The authors suggest that this result may be explained by introgressive hybridization
, as the tested individuals of these two taxa originated from a region of sympatry
in southern Thailand; the precise origin of one of the N. coucang individuals was not known. This hypothesis was corroborated by a 2007 study that compared the variations in mitochondrial DNA sequences between N. bengalensis and N. coucang, and suggested that there has been gene flow
between the two species.
due to the dark inverse teardrop markings around the eyes which meet the dark dorsal
stripe on the back of the head. It tends to have a much more distinct white stripe between the eyes, more distinct dark coloring around the eyes, and a browner coat than the Bengal slow loris which is larger, grayer, and shows less contrast. The Sunda slow loris has less white facial coloring than the much smaller pygmy slow loris
. Local color variations are known to occur.
It measures between 27 and 38 cm (10.6 and 15 in) and weighs 599 and 685 g (21.1 and 24.2 oz). Unlike the Bengal slow loris, the Sunda slow loris does not show sexual dimorphism
by weight. The vestigial tail, hidden beneath the fur, is reduced to a stump. It has a toothcomb
, six forward-facing teeth on the bottom jaw, which includes the lower
incisor
s and the canine teeth
. The structure is generally used for grooming in other strepsirhine
primates, but lorises also use it to scrape off gum when foraging. It has a shortened second digit, and the hands have a strong grip. Like other lorises, it excretes a strong-smelling liquid from gland
s beneath its arms which is used in communication.
One major distinguishing feature between all loris species is locomotion: the Sunda slow loris moves slowly through trees on all four limbs, typically with three limbs attached to a support at a time. Its movement has been described as unique; similar to crawling, or as if it was climbing in every direction, the Sunda slow loris changes direction or moves between branches with little noise or change in speed. In captivity, about a quarter of its time is spent moving quadrupedally, a quarter suspended or hanging, a quarter climbing, and a quarter clasping multiple branches (bridging). It may hang below a branch by one or both feet for long periods of time.
and nocturnal primate, resting by day in the forks of trees, or in thick vegetation and feeding on fruit and insects by night. Unlike other loris species, it remains in trees most of its life: while the Bengal slow loris
will often sleep on the ground, the Sunda slow loris sleeps in a ball in branches or foliage. It usually sleeps alone but has been observed to sleep with several conspecifics (individuals of the same species), including other adults. Adults live in overlapping ranges of 0.004 square kilometre.
Despite its slow metabolism
rate, the Sunda slow loris has a high-energy diet. Its slow lifestyle may be due to the energy costs of detoxifying certain secondary plant compounds in many genera
of food plants their diets. The largest amount of time is spent eating phloem
sap (34.9%), floral nectar and nectar-producing plant parts (31.7%), and fruits (22.5%). It also consumes gums and arthropods such as spiders and insects. Gum is taken by licking wounds on trees. They are also known to feed on molluscs
, including the giant land snail Achatina fulica, and birds' eggs.
All slow loris species produce a toxin
in glands on the insides of their elbows. This is spread across their bodies and those of their offspring using the toothcomb
while grooming. When threatened with predators, the Sunda slow loris can bite, roll into a ball exposing its toxic saliva-covered fur, or roll up and drop from the trees. However, the primary method of predator avoidance is crypsis
, whereby it hides. The Asiatic Reticulated Python, the Changeable Hawk-eagle and the Bornean Orangutan
have been recorded as predators of the Sunda slow loris.
single male/single female social system, though are mainly known to be solitary. One study showed only 8% of the species' active time was spent near other individuals. Where home ranges overlap, spatial groups are formed. These groups consist of one male, one female and up to three younger individuals. The interactions between these individuals are largely friendly; they include allogrooming
, following, pant-growling, and click-calling, although social behaviors only make up around 3% of the activity budget. When it comes into contact with conspecifics from other home ranges there is usually no reaction as home range
s are not defended. In captivity however, it can be aggressive with other individuals. Males have shown antagonistic behaviors such as attacks, pursuits, threats, assertion, fighting, and subordination. The fighting often results in serious injury. Despite this, they are known to be generally sociable in captivity, with allogrooming being the most common social behavior.
to avoid predators, they do not make alarm calls. Infants emits clicks and squeaks when disturbed. During estrus, females make whistle calls when in visual contact with a male. When exploring new environments and during handling, it makes ultrasonic
vocalisations out of the human hearing range.
Olfactory
communication is very important in this species. It has roles in alerting others of the identity, physical state and position of the individual. It is also important in reproduction. Like other slow lorises, the Sunda slow loris has glands on its elbows that exude oils. The gland is licked to spread scent and is thought to have evolved for communication, but it is toxic to humans. If the person is allergic to the animal they can go into shock and could even die. It also has glands on its anus
and can signal conspecifics by perineal
rubbing which deposits urine. When it locates the scent of another slow loris it may rub its face on the substrate
where the scent was found.
The Sunda slow loris may grin or bare its teeth. When stressed, infants may grin, while adults bear their teeth to show aggression or fear, but also during play.
size is small compared with similar sized promsimians, which is indicative of monogamy
. In the wild the mating system of the Sunda slow loris is thought to vary between populations.
Sexual maturity is reached between the ages of 18 and 24 months in females, and can be reached by 17 months in males. It is polyestrous
, having many periods of sexual receptivity during a year. In captivity however, there is a clear birth peak between March and May. It has been observed that reproductive patterns of captive prosimian
s in the northern hemisphere are altered. The estrus cycle lasts 29–45 days, with most copulations occurring on the same day.
Females in estrus are followed by males, with copulation initiated by the female. The female will hang from a branch and may vocalise. The male will hold the female and the branch and copulate with her. Urine-marking and vocalising are also used by the female to solicit mating. The male may create a mating plug
following copulation.
The gestation period
averages 192.2 days, after which one young is born, although twin
ning has been observed. Both males and females will disperse in the wild, this occurs between 16 and 27 months.
, on the islands of Sumatra
, Batam
and Galang in the Riau Archipelago
, and Pulau Tebingtinggi and Bunguran
in the northern Natuna Islands
; in Malaysia on the Malay Peninsula
and Pulau Tioman; in the southern peninsular of Thailand
; and Singapore
.
The Sunda slow loris is sympatric (shares its range) with the Bengal slow loris
in Thailand and hybridisation has occurred.
". In June 2007 it was transferred from CITES Appendix II to Appendix I, indicating a true concern about the state of internation trade in this species, an act now forbidden by international law. It is also protected by Indonesian law, though the law does not seem to be strictly enforced. Its population size is unknown and further studies need to be carried out to confirm their conservation status.
The Sunda slow loris is greatly threatened by the pet trade
, and is sold as an exotic pet
throughout southeast Asia. The slow lorises are the most commonly traded protected primates in southeast Asia. When sold as a pet it often will have its teeth pulled out to prevent injury to the owner. This may cause dental infections which have up to a 90% death rate. Once it has lost its teeth, reintroduction to the wild is impossible. Due to a very high mortality rate in captivity due to stress, improper nutrition and infection, the pet trade is inflated by replacements. With a greater purchasing power, the increasing human populations in the species' range could have an even more serious impact.
The Sunda slow loris is further threatened by gathering for illegal traditional medicine
. The fur is reported to heal wounds, the flesh to cure epilepsy, eyes are used in love potions, and the meat is reported to cure asthma and stomach problems. It is also killed as a crop pest. Severe habitat loss
and degradation over large areas of its range have caused large population declines, even though the species is more adaptable to anthropogenic
habitats than other primates in the region. The resulting fragmentation
has restricted species dispersal
as it depends on continuous canopy cover to move from tree to tree.
Strepsirrhini
The clade Strepsirrhini is one of the two suborders of primates. Madagascar's only non-human primates are strepsirrhines, and others can be found in southeast Asia and Africa...
primate
Primate
A primate is a mammal of the order Primates , which contains prosimians and simians. Primates arose from ancestors that lived in the trees of tropical forests; many primate characteristics represent adaptations to life in this challenging three-dimensional environment...
and a species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of slow loris
Slow loris
Slow lorises are a group of five species of strepsirrhine primates which make up the genus Nycticebus. Found in South and Southeast Asia, they range from Northeast India in the west to the Philippines in the east, and from the Yunnan province in China in the north to the island of Java in the south...
native to Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
, western Malaysia, southern Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
and Singapore
Singapore
Singapore , officially the Republic of Singapore, is a Southeast Asian city-state off the southern tip of the Malay Peninsula, north of the equator. An island country made up of 63 islands, it is separated from Malaysia by the Straits of Johor to its north and from Indonesia's Riau Islands by the...
. It measures 27 to 38 cm (10.6 to 15 in) from head to tail and weighs between 599 and 685 g (21.1 and 24.2 oz). Like other slow lorises, it has a wet nose (rhinarium
Rhinarium
The rhinarium is the moist, naked surface around the nostrils of the nose in most mammals. In actual scientific usage it is typically called a "wet snout" or "wet nose" from its moist and shiny appearance...
), a round head, small ears hidden in thick fur, a flat face, large eyes, small ears and a vestigial tail.
The Sunda slow loris is nocturnal and arboreal
Arboreal locomotion
Arboreal locomotion is the locomotion of animals in trees. In every habitat in which trees are present, animals have evolved to move in them. Some animals may only scale trees occasionally, while others are exclusively arboreal. These habitats pose numerous mechanical challenges to animals...
, typically occurring in evergreen forest
Evergreen forest
An temperate evergreen forest is a forest consisting entirely or mainly of evergreen trees that retain green foliage all year round. Such forests exist in the tropics primarily as broadleaf evergreens, and in temperate and boreal latitudes primarily as coniferous evergreens.-Tropical evergreen...
s. It prefers rainforests with continuous dense canopies and has an extremely low metabolic rate compared to other mammals of its size. Its diet consists of sap
Plant sap
Sap is a fluid transported in xylem cells or phloem sieve tube elements of a plant. It transports water and nutrients throughout the plant....
, floral nectar, fruit and arthropods. It will feed on exudates such as gum
Gum (botany)
Gum is a sap or other resinous material associated with certain species of the plant kingdom. This material is often polysaccharide-based and most frequently is associated with woody plants, particularly under the bark or as a seed coating...
and sap by licking wounds in trees. The species is generally solitary; one study showed only 8% of its active time was spent near other individuals. Social behavior makes up a very small part of the activity budget, though it has monogamous mating system with the offspring living with the parents. It sleeps during the day, rolled up in a ball in hidden parts of trees above the ground, often on branches, twigs, palm fronds, or liana
Liana
A liana is any of various long-stemmed, woody vines that are rooted in the soil at ground level and use trees, as well as other means of vertical support, to climb up to the canopy to get access to well-lit areas of the forest. Lianas are especially characteristic of tropical moist deciduous...
s. The species is polyoestrous
Estrous cycle
The estrous cycle comprises the recurring physiologic changes that are induced by reproductive hormones in most mammalian placental females. Estrous cycles start after puberty in sexually mature females and are interrupted by anestrous phases or pregnancies...
, usually giving birth to a single offspring after a gestation period
Gestation period
For mammals the gestation period is the time in which a fetus develops, beginning with fertilization and ending at birth. The duration of this period varies between species.-Duration:...
of 192 days. The young disperses between 16 and 27 months, generally when it is sexually mature
Sexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...
.
The species is listed as "Vulnerable
Vulnerable species
On 30 January 2010, the IUCN Red List of Threatened Species identified 9694 Vulnerable species, subspecies and varieties, stocks and sub-populations.-References:...
" on the IUCN Red List
IUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
. It is threatened with extinction due to a growing demand in the exotic pet
Exotic pet
An exotic pet is a rare or unusual animal pet, or an animal kept as a pet which is not commonly thought of as a pet.The definition is an evolving one; some rodents, reptiles, and amphibians have become firmly enough established in the world of animal fancy to no longer be considered exotic...
trade, and has become one of the most abundant primate species on sale at Indonesian pet markets. Its teeth are often pulled out before being sold as pets which can result in infection and/or death, this process makes reintroduction to the wild impossible. It also suffers from habitat loss
Habitat destruction
Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity mainly for the purpose of...
, which has been severe in the areas in which it is found.
Etymology
The common nameCommon name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
, Sunda slow loris, refers to the Sunda Islands
Sunda Islands
The Sunda Islands are a group of islands that form part of the Malay archipelago.They are further divided into the Greater Sunda Islands and the Lesser Sunda Islands.-Administration:...
, a group of islands in the western part of the Malay archipelago where it is found. Another common name for the species is the Greater Slow Loris. The specific name, coucang, derives from kukang, its common name in Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
. It is commonly known as malu-malu, meaning "shy" in Indonesian
Indonesian language
Indonesian is the official language of Indonesia. Indonesian is a normative form of the Riau Islands dialect of Malay, an Austronesian language which has been used as a lingua franca in the Indonesian archipelago for centuries....
, and also as bukang or Kalamasan. It is sometimes called Kuskus, because local people do not distinguish between the slow loris and Cuscus
Cuscus
Cuscus is the common name generally given to the species within the four genera of Australasian possum:* Ailurops* Phalanger* Spilocuscus* Strigocuscus...
, a group of Australasian possum
Possum
A possum is any of about 70 small to medium-sized arboreal marsupial species native to Australia, New Guinea, and Sulawesi .Possums are quadrupedal diprotodont marsupials with long tails...
s. In Malaysia they are sometimes known as kongkang or kera duku; kera is Malay for monkey while duku is the fruit-bearing tree, Lansium domesticum
Lansium domesticum
Lansium domesticum, also known as langsat or lanzones, is a fruit from the family Meliaceae. The plant, which originates from western Southeast Asia. It is the provincial flower for the Indonesian province of South Sumatra.-Names:...
. In Thailand, it is called ling lom (ลิงลม), which translates as "wind monkey".
Taxonomy and phylogeny
The Sunda slow loris was first describedSpecies description
A species description or type description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species which have been described previously, or are...
in 1785 by the Dutch physician and naturalist Pieter Boddaert
Pieter Boddaert
Pieter Boddaert was a Dutch physician and naturalist.Boddaert was the son of a Middelburg jurist and poet by the same name . Pieter Jr. obtained his M.D. at the University of Utrecht in 1764 and there became a lecturer on natural history. Fourteen letters survive of his correspondence with Carl...
under the name Tardigradus coucang. However, its discovery dates to 1770, when the Dutchman Arnout Vosmaer (1720–1799) described a specimen of it as a type of sloth
Sloth
Sloths are the six species of medium-sized mammals belonging to the families Megalonychidae and Bradypodidae , part of the order Pilosa and therefore related to armadillos and anteaters, which sport a similar set of specialized claws.They are arboreal residents of the jungles of Central and South...
. Vosmaer gave it the French name "le paresseuz pentadactyle du Bengale" ("the five-fingered sloth of Bengal"), but Boddaert later argued that it was more closely aligned with the lorises of Ceylon
Sri Lanka
Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka is a country off the southern coast of the Indian subcontinent. Known until 1972 as Ceylon , Sri Lanka is an island surrounded by the Indian Ocean, the Gulf of Mannar and the Palk Strait, and lies in the vicinity of India and the...
(now Sri Lanka) and Bengal.
Between 1800 and 1907, several other slow loris species were described, but in 1952 the primatologist William Charles Osman Hill
William Charles Osman Hill
William Charles Osman Hill was a British anatomist, primatologist, and a leading authority on primate anatomy during the 20th century...
consolidated all the slow lorises in one species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
, N. coucang, in his influential book Primates: Comparative Anatomy and Taxonomy. In 1971 Colin Groves
Colin Groves
Colin Peter Groves is Professor of Biological Anthropology at the Australian National University in Canberra, Australia.Born in England on 24 June 1942, Colin Groves completed a Bachelor of Science at University College London in 1963, and a Doctor of Philosophy at the Royal Free Hospital School of...
recognized the pygmy slow loris
Pygmy Slow Loris
The pygmy slow loris is a rare species of loris found in the tropical dry forests of Vietnam, Laos, southern China, and east of the Mekong River in Cambodia....
(N. pygmaeus) as a separate species, and divided N. coucang into four subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
, while in 2001 Groves opined there were three species (N. coucang, N. pygmaeus, and N. bengalensis), and that N. coucang had three subspecies (Nycticebus coucang coucang, N. c. menagensis, and N. c. javanicus). These subspecies were promoted in 2010 to species status—the Javan slow loris
Javan slow loris
The Javan slow loris is a strepsirrhine primate and a species of slow loris native to the western and central portions of the island of Java, in Indonesia...
(N. javanicus) and Bornean slow loris
Bornean Slow Loris
The Bornean slow loris or Philippine slow loris is a strepsirrhine primate and a species of slow loris that is native to the island of Borneo , the nearby islands of Belitung and Bangka in Indonesia, and the Sulu Archipelago in the Philippines...
(N. menagensis)—leaving the Sunda slow loris without subspecies. Species differentiation was based largely on differences in morphology, such as size, fur color, and head markings.
When Étienne Geoffroy Saint-Hilaire
Étienne Geoffroy Saint-Hilaire
Étienne Geoffroy Saint-Hilaire was a French naturalist who established the principle of "unity of composition". He was a colleague of Jean-Baptiste Lamarck and expanded and defended Lamarck's evolutionary theories...
defined the genus Nycticebus in 1812, he made the Sunda slow loris the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
. This was questioned in 1921 by British zoologist
Zoology
Zoology |zoölogy]]), is the branch of biology that relates to the animal kingdom, including the structure, embryology, evolution, classification, habits, and distribution of all animals, both living and extinct...
Oldfield Thomas
Oldfield Thomas
Oldfield Thomas FRS was a British zoologist.Thomas worked at the Natural History Museum on mammals, describing about 2,000 new species and sub-species for the first time. He was appointed to the Museum Secretary's office in 1876, transferring to the Zoological Department in 1878...
, who noted that there was some confusion over the specimen used as the type specimen. Instead, he suggested that the type specimen was actually the Bengal slow loris
Bengal Slow Loris
The Bengal slow loris or northern slow loris is a strepsirrhine primate and a species of slow loris native to the Indian subcontinent and Indochina. Its geographic range is larger than that of any other slow loris species...
(N. bengalensis). There was also some confusion during the 1800s when Boddaert's Tardigradus coucang was mistaken for Carl Linnaeus' Lemur tardigradus, which was described in the 10th edition of Systema Naturæ
10th edition of Systema Naturae
The 10th edition of Systema Naturae was a book written by Carl Linnaeus and published in two volumes in 1758 and 1759, which marks the starting point of zoological nomenclature...
(1758) and referred to a slender loris. However, this was clarified in 1902 by mammalogist
Mammalogy
In zoology, mammalogy is the study of mammals – a class of vertebrates with characteristics such as homeothermic metabolism, fur, four-chambered hearts, and complex nervous systems...
s Witmer Stone
Witmer Stone
Witmer Stone was an American ornithologist, botanist, and mammalogist, and was considered one of the last of the “great naturalists.” Stone is remembered principally as an ornithologist. He was president of the American Ornithologists’ Union 1920–23, and was editor of the AOU’s periodical The...
and James A. G. Rehn.
The species has 50 chromosomes (2n=50), and it genome size
Genome size
Genome size is the total amount of DNA contained within one copy of a single genome. It is typically measured in terms of mass in picograms or less frequently in Daltons or as the total number of nucleotide base pairs typically in megabases . One picogram equals 978 megabases...
is 3.58 pg. Of its chromosomes, 22 are metacentric
Centromere
A centromere is a region of DNA typically found near the middle of a chromosome where two identical sister chromatids come closest in contact. It is involved in cell division as the point of mitotic spindle attachment...
, 26 are submetacentric
Centromere
A centromere is a region of DNA typically found near the middle of a chromosome where two identical sister chromatids come closest in contact. It is involved in cell division as the point of mitotic spindle attachment...
, and none are acrocentric
Centromere
A centromere is a region of DNA typically found near the middle of a chromosome where two identical sister chromatids come closest in contact. It is involved in cell division as the point of mitotic spindle attachment...
. Its X chromosome
X chromosome
The X chromosome is one of the two sex-determining chromosomes in many animal species, including mammals and is common in both males and females. It is a part of the XY sex-determination system and X0 sex-determination system...
is submetacentric, and its Y chromosome
Y chromosome
The Y chromosome is one of the two sex-determining chromosomes in most mammals, including humans. In mammals, it contains the gene SRY, which triggers testis development if present. The human Y chromosome is composed of about 60 million base pairs...
is metacentric.
To help clarify species and subspecies boundaries, and to establish whether morphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
-based classifications were consistent with evolutionary relationships, the phylogenetic relationships within the genus Nycticebus have been investigated using DNA sequences derived from the mitochondrial
Mitochondrial DNA
Mitochondrial DNA is the DNA located in organelles called mitochondria, structures within eukaryotic cells that convert the chemical energy from food into a form that cells can use, adenosine triphosphate...
markers D-loop
D-loop
In molecular biology, a displacement loop or D-loop is a DNA structure where the two strands of a double-stranded DNA molecule are separated for a stretch and held apart by a third strand of DNA. The third strand has a base sequence which is complementary to one of the main strands and pairs with...
and cytochrome b
Cytochrome b
Cytochrome b/b6 is the main subunit of transmembrane cytochrome bc1 and b6f complexes. In addition, it commonly refers to a region of mtDNA used for population genetics and phylogenetics.- Function :...
. Although most of the recognized lineages of Nycticebus (including the pygmy slow loris (N. pygmaeus), Bornean slow loris (N. menagensis) and the Javan slow loris (N. javanicus)) were shown to be genetically distinct, the analysis suggested that DNA sequences from some individuals of Sunda slow loris (N. coucang) and Bengal slow loris (N. bengalensis) apparently share a closer evolutionary relationship with each other than with members of their own species. The authors suggest that this result may be explained by introgressive hybridization
Introgression
Introgression, also known as introgressive hybridization, in genetics is the movement of a gene from one species into the gene pool of another by the repeated backcrossing of an interspecific hybrid with one of its parent species...
, as the tested individuals of these two taxa originated from a region of sympatry
Sympatry
In biology, two species or populations are considered sympatric when they exist in the same geographic area and thus regularly encounter one another. An initially-interbreeding population that splits into two or more distinct species sharing a common range exemplifies sympatric speciation...
in southern Thailand; the precise origin of one of the N. coucang individuals was not known. This hypothesis was corroborated by a 2007 study that compared the variations in mitochondrial DNA sequences between N. bengalensis and N. coucang, and suggested that there has been gene flow
Gene flow
In population genetics, gene flow is the transfer of alleles of genes from one population to another.Migration into or out of a population may be responsible for a marked change in allele frequencies...
between the two species.
Physical description
The Sunda slow loris has dark rings around its large eyes, a white nose with a whitish strip that extends to the forehead and a dark stripe that stretches from the back of the head along the spine. Its soft, thick, woolly fur ranges from light brown to deep reddish brown, with a lighter underside. The species is distinct from the Bengal slow lorisBengal Slow Loris
The Bengal slow loris or northern slow loris is a strepsirrhine primate and a species of slow loris native to the Indian subcontinent and Indochina. Its geographic range is larger than that of any other slow loris species...
due to the dark inverse teardrop markings around the eyes which meet the dark dorsal
Dorsum (anatomy)
In anatomy, the dorsum is the upper side of animals that typically run, fly, or swim in a horizontal position, and the back side of animals that walk upright. In vertebrates the dorsum contains the backbone. The term dorsal refers to anatomical structures that are either situated toward or grow...
stripe on the back of the head. It tends to have a much more distinct white stripe between the eyes, more distinct dark coloring around the eyes, and a browner coat than the Bengal slow loris which is larger, grayer, and shows less contrast. The Sunda slow loris has less white facial coloring than the much smaller pygmy slow loris
Pygmy Slow Loris
The pygmy slow loris is a rare species of loris found in the tropical dry forests of Vietnam, Laos, southern China, and east of the Mekong River in Cambodia....
. Local color variations are known to occur.
It measures between 27 and 38 cm (10.6 and 15 in) and weighs 599 and 685 g (21.1 and 24.2 oz). Unlike the Bengal slow loris, the Sunda slow loris does not show sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
by weight. The vestigial tail, hidden beneath the fur, is reduced to a stump. It has a toothcomb
Toothcomb
A toothcomb is an anatomical structure found in strepsirrhine primates, which includes lemurs, lorises and galagos. A toothcomb consists of long, flat forward-angled teeth, and includes the lower incisors and the canine teeth...
, six forward-facing teeth on the bottom jaw, which includes the lower
Mandible
The mandible pronunciation or inferior maxillary bone forms the lower jaw and holds the lower teeth in place...
incisor
Incisor
Incisors are the first kind of tooth in heterodont mammals. They are located in the premaxilla above and mandible below.-Function:...
s and the canine teeth
Canine tooth
In mammalian oral anatomy, the canine teeth, also called cuspids, dogteeth, fangs, or eye teeth, are relatively long, pointed teeth...
. The structure is generally used for grooming in other strepsirhine
Strepsirrhini
The clade Strepsirrhini is one of the two suborders of primates. Madagascar's only non-human primates are strepsirrhines, and others can be found in southeast Asia and Africa...
primates, but lorises also use it to scrape off gum when foraging. It has a shortened second digit, and the hands have a strong grip. Like other lorises, it excretes a strong-smelling liquid from gland
Gland
A gland is an organ in an animal's body that synthesizes a substance for release of substances such as hormones or breast milk, often into the bloodstream or into cavities inside the body or its outer surface .- Types :...
s beneath its arms which is used in communication.
One major distinguishing feature between all loris species is locomotion: the Sunda slow loris moves slowly through trees on all four limbs, typically with three limbs attached to a support at a time. Its movement has been described as unique; similar to crawling, or as if it was climbing in every direction, the Sunda slow loris changes direction or moves between branches with little noise or change in speed. In captivity, about a quarter of its time is spent moving quadrupedally, a quarter suspended or hanging, a quarter climbing, and a quarter clasping multiple branches (bridging). It may hang below a branch by one or both feet for long periods of time.
Behavior and ecology
Like other slow lorises, the Sunda slow loris is an arborealArboreal locomotion
Arboreal locomotion is the locomotion of animals in trees. In every habitat in which trees are present, animals have evolved to move in them. Some animals may only scale trees occasionally, while others are exclusively arboreal. These habitats pose numerous mechanical challenges to animals...
and nocturnal primate, resting by day in the forks of trees, or in thick vegetation and feeding on fruit and insects by night. Unlike other loris species, it remains in trees most of its life: while the Bengal slow loris
Bengal Slow Loris
The Bengal slow loris or northern slow loris is a strepsirrhine primate and a species of slow loris native to the Indian subcontinent and Indochina. Its geographic range is larger than that of any other slow loris species...
will often sleep on the ground, the Sunda slow loris sleeps in a ball in branches or foliage. It usually sleeps alone but has been observed to sleep with several conspecifics (individuals of the same species), including other adults. Adults live in overlapping ranges of 0.004 square kilometre.
Despite its slow metabolism
Metabolism
Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...
rate, the Sunda slow loris has a high-energy diet. Its slow lifestyle may be due to the energy costs of detoxifying certain secondary plant compounds in many genera
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of food plants their diets. The largest amount of time is spent eating phloem
Phloem
In vascular plants, phloem is the living tissue that carries organic nutrients , in particular, glucose, a sugar, to all parts of the plant where needed. In trees, the phloem is the innermost layer of the bark, hence the name, derived from the Greek word "bark"...
sap (34.9%), floral nectar and nectar-producing plant parts (31.7%), and fruits (22.5%). It also consumes gums and arthropods such as spiders and insects. Gum is taken by licking wounds on trees. They are also known to feed on molluscs
Mollusca
The Mollusca , common name molluscs or mollusksSpelled mollusks in the USA, see reasons given in Rosenberg's ; for the spelling mollusc see the reasons given by , is a large phylum of invertebrate animals. There are around 85,000 recognized extant species of molluscs. Mollusca is the largest...
, including the giant land snail Achatina fulica, and birds' eggs.
All slow loris species produce a toxin
Toxin
A toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...
in glands on the insides of their elbows. This is spread across their bodies and those of their offspring using the toothcomb
Toothcomb
A toothcomb is an anatomical structure found in strepsirrhine primates, which includes lemurs, lorises and galagos. A toothcomb consists of long, flat forward-angled teeth, and includes the lower incisors and the canine teeth...
while grooming. When threatened with predators, the Sunda slow loris can bite, roll into a ball exposing its toxic saliva-covered fur, or roll up and drop from the trees. However, the primary method of predator avoidance is crypsis
Crypsis
In ecology, crypsis is the ability of an organism to avoid observation or detection by other organisms. It may be either a predation strategy or an antipredator adaptation, and methods include camouflage, nocturnality, subterranean lifestyle, transparency, and mimicry...
, whereby it hides. The Asiatic Reticulated Python, the Changeable Hawk-eagle and the Bornean Orangutan
Bornean Orangutan
The Bornean orangutan, Pongo pygmaeus, is a species of orangutan native to the island of Borneo. Together with the slightly smaller Sumatran orangutan, it belongs to the only genus of great apes native to Asia....
have been recorded as predators of the Sunda slow loris.
Social systems
The Sunda slow loris may fit into the monogamousMonogamy
Monogamy /Gr. μονός+γάμος - one+marriage/ a form of marriage in which an individual has only one spouse at any one time. In current usage monogamy often refers to having one sexual partner irrespective of marriage or reproduction...
single male/single female social system, though are mainly known to be solitary. One study showed only 8% of the species' active time was spent near other individuals. Where home ranges overlap, spatial groups are formed. These groups consist of one male, one female and up to three younger individuals. The interactions between these individuals are largely friendly; they include allogrooming
Social grooming
In social animals, including humans, social grooming or allogrooming is an activity in which individuals in a group clean or maintain one another's body or appearance. It is a major social activity, and a means by which animals who live in proximity can bond and reinforce social structures, family...
, following, pant-growling, and click-calling, although social behaviors only make up around 3% of the activity budget. When it comes into contact with conspecifics from other home ranges there is usually no reaction as home range
Home range
Home range is the area where an animal lives and travels in. It is closely related to, but not identical with, the concept of "territory".The concept that can be traced back to a publication in 1943 by W. H. Burt, who constructed maps delineating the spatial extent or outside boundary of an...
s are not defended. In captivity however, it can be aggressive with other individuals. Males have shown antagonistic behaviors such as attacks, pursuits, threats, assertion, fighting, and subordination. The fighting often results in serious injury. Despite this, they are known to be generally sociable in captivity, with allogrooming being the most common social behavior.
Communication
There are eight distinct call types made by Sunda slow loris adults, which can be divided into two categories: contact and contact-seeking calls such as whistles and short keckers (a social play and attention-seeking call), and aggressive and defensive calls such as long keckers, screams, snarls and grunts. Because they rely on crypsisCrypsis
In ecology, crypsis is the ability of an organism to avoid observation or detection by other organisms. It may be either a predation strategy or an antipredator adaptation, and methods include camouflage, nocturnality, subterranean lifestyle, transparency, and mimicry...
to avoid predators, they do not make alarm calls. Infants emits clicks and squeaks when disturbed. During estrus, females make whistle calls when in visual contact with a male. When exploring new environments and during handling, it makes ultrasonic
Ultrasound
Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...
vocalisations out of the human hearing range.
Olfactory
Olfaction
Olfaction is the sense of smell. This sense is mediated by specialized sensory cells of the nasal cavity of vertebrates, and, by analogy, sensory cells of the antennae of invertebrates...
communication is very important in this species. It has roles in alerting others of the identity, physical state and position of the individual. It is also important in reproduction. Like other slow lorises, the Sunda slow loris has glands on its elbows that exude oils. The gland is licked to spread scent and is thought to have evolved for communication, but it is toxic to humans. If the person is allergic to the animal they can go into shock and could even die. It also has glands on its anus
Anus
The anus is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, unwanted semi-solid matter produced during digestion, which, depending on the type of animal, may be one or more of: matter which the animal cannot digest,...
and can signal conspecifics by perineal
Perineum
In human anatomy, the perineum is a region of the body including the perineal body and surrounding structures...
rubbing which deposits urine. When it locates the scent of another slow loris it may rub its face on the substrate
Substrate (biology)
In biology a substrate is the surface a plant or animal lives upon and grows on. A substrate can include biotic or abiotic materials and animals. For example, encrusting algae that lives on a rock can be substrate for another animal that lives on top of the algae. See also substrate .-External...
where the scent was found.
The Sunda slow loris may grin or bare its teeth. When stressed, infants may grin, while adults bear their teeth to show aggression or fear, but also during play.
Reproduction
Reproduction is one of the few times the Sunda slow loris aggregates with conspecifics, as it is largely solitary. One study recorded that the most slow lorises ever seen together was six; this appeared to be a female in estrus and five males following her. This may suggest a more promiscuous mating system, where females mate with more than one male. Despite this, its testisTesticle
The testicle is the male gonad in animals. Like the ovaries to which they are homologous, testes are components of both the reproductive system and the endocrine system...
size is small compared with similar sized promsimians, which is indicative of monogamy
Monogamy
Monogamy /Gr. μονός+γάμος - one+marriage/ a form of marriage in which an individual has only one spouse at any one time. In current usage monogamy often refers to having one sexual partner irrespective of marriage or reproduction...
. In the wild the mating system of the Sunda slow loris is thought to vary between populations.
Sexual maturity is reached between the ages of 18 and 24 months in females, and can be reached by 17 months in males. It is polyestrous
Estrous cycle
The estrous cycle comprises the recurring physiologic changes that are induced by reproductive hormones in most mammalian placental females. Estrous cycles start after puberty in sexually mature females and are interrupted by anestrous phases or pregnancies...
, having many periods of sexual receptivity during a year. In captivity however, there is a clear birth peak between March and May. It has been observed that reproductive patterns of captive prosimian
Prosimian
Prosimians are a grouping of mammals defined as being primates, but not monkeys or apes. They include, among others, lemurs, bushbabies, and tarsiers. They are considered to have characteristics that are more primitive than those of monkeys and apes. Prosimians are the only primates native to...
s in the northern hemisphere are altered. The estrus cycle lasts 29–45 days, with most copulations occurring on the same day.
Females in estrus are followed by males, with copulation initiated by the female. The female will hang from a branch and may vocalise. The male will hold the female and the branch and copulate with her. Urine-marking and vocalising are also used by the female to solicit mating. The male may create a mating plug
Mating plug
right|thumbnail|A mating plug in a female [[Richardson's ground squirrel]] A mating plug, also known as a copulation plug, sperm plug, vaginal plug, or sphragis, is gelatinous secretion used in the mating of some species. It is deposited by a male into a female genital tract and later hardens into...
following copulation.
The gestation period
Gestation period
For mammals the gestation period is the time in which a fetus develops, beginning with fertilization and ending at birth. The duration of this period varies between species.-Duration:...
averages 192.2 days, after which one young is born, although twin
Twin
A twin is one of two offspring produced in the same pregnancy. Twins can either be monozygotic , meaning that they develop from one zygote that splits and forms two embryos, or dizygotic because they develop from two separate eggs that are fertilized by two separate sperm.In contrast, a fetus...
ning has been observed. Both males and females will disperse in the wild, this occurs between 16 and 27 months.
Distribution and habitat
The Sunda slow loris is found in continuous canopy tropical rainforests. It is adaptable and will also live in other types of habitat. It is found in IndonesiaIndonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
, on the islands of Sumatra
Sumatra
Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...
, Batam
Batam
Batam is an island and city in Riau Islands Province of Indonesia, known for its free trade zone area as part of the Sijori Growth Triangle, is located off Singapore's south coast...
and Galang in the Riau Archipelago
Riau Archipelago
Not to be confused with Riau Islands Province, a province of Indonesia.The Riau Archipelago is the core group of islands within the Riau Islands Province in Indonesia, and located south of Singapore...
, and Pulau Tebingtinggi and Bunguran
Bunguran
Bunguran is a small archipelago of Indonesia, located in the South China Sea....
in the northern Natuna Islands
Natuna Islands
The Natuna Islands archipelago is located in the Natuna Sea in the larger Tudjuh Archipelago, off the northwest coast of Borneo. The islands are administratively part of the Riau Islands province of Indonesia and are the northernmost non-disputed island group of Indonesia...
; in Malaysia on the Malay Peninsula
Malay Peninsula
The Malay Peninsula or Thai-Malay Peninsula is a peninsula in Southeast Asia. The land mass runs approximately north-south and, at its terminus, is the southern-most point of the Asian mainland...
and Pulau Tioman; in the southern peninsular of Thailand
Kra Isthmus
The Kra Isthmus is the narrow land bridge which connects the Malay Peninsula with the mainland of Asia, and popularly named "The Devil's Neck".-Geography:...
; and Singapore
Singapore
Singapore , officially the Republic of Singapore, is a Southeast Asian city-state off the southern tip of the Malay Peninsula, north of the equator. An island country made up of 63 islands, it is separated from Malaysia by the Straits of Johor to its north and from Indonesia's Riau Islands by the...
.
The Sunda slow loris is sympatric (shares its range) with the Bengal slow loris
Bengal Slow Loris
The Bengal slow loris or northern slow loris is a strepsirrhine primate and a species of slow loris native to the Indian subcontinent and Indochina. Its geographic range is larger than that of any other slow loris species...
in Thailand and hybridisation has occurred.
Conservation
According to the 2008 International Union for Conservation of Nature (IUCN) Red List assessment, the Sunda slow loris was evaluated as "VulnerableVulnerable species
On 30 January 2010, the IUCN Red List of Threatened Species identified 9694 Vulnerable species, subspecies and varieties, stocks and sub-populations.-References:...
". In June 2007 it was transferred from CITES Appendix II to Appendix I, indicating a true concern about the state of internation trade in this species, an act now forbidden by international law. It is also protected by Indonesian law, though the law does not seem to be strictly enforced. Its population size is unknown and further studies need to be carried out to confirm their conservation status.
The Sunda slow loris is greatly threatened by the pet trade
Wildlife trade
The international wildlife trade is a serious conservation problem, addressed by the United Nations' Convention of International Trade in Endangered Species of Wild Fauna and Flora CITES, which currently has 175 member countries called Parties. The 15th meeting of the Parties took place in Doha,...
, and is sold as an exotic pet
Exotic pet
An exotic pet is a rare or unusual animal pet, or an animal kept as a pet which is not commonly thought of as a pet.The definition is an evolving one; some rodents, reptiles, and amphibians have become firmly enough established in the world of animal fancy to no longer be considered exotic...
throughout southeast Asia. The slow lorises are the most commonly traded protected primates in southeast Asia. When sold as a pet it often will have its teeth pulled out to prevent injury to the owner. This may cause dental infections which have up to a 90% death rate. Once it has lost its teeth, reintroduction to the wild is impossible. Due to a very high mortality rate in captivity due to stress, improper nutrition and infection, the pet trade is inflated by replacements. With a greater purchasing power, the increasing human populations in the species' range could have an even more serious impact.
The Sunda slow loris is further threatened by gathering for illegal traditional medicine
Traditional medicine
Traditional medicine comprises unscientific knowledge systems that developed over generations within various societies before the era of modern medicine...
. The fur is reported to heal wounds, the flesh to cure epilepsy, eyes are used in love potions, and the meat is reported to cure asthma and stomach problems. It is also killed as a crop pest. Severe habitat loss
Habitat destruction
Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity mainly for the purpose of...
and degradation over large areas of its range have caused large population declines, even though the species is more adaptable to anthropogenic
Anthropogenic
Human impact on the environment or anthropogenic impact on the environment includes impacts on biophysical environments, biodiversity and other resources. The term anthropogenic designates an effect or object resulting from human activity. The term was first used in the technical sense by Russian...
habitats than other primates in the region. The resulting fragmentation
Habitat fragmentation
Habitat fragmentation as the name implies, describes the emergence of discontinuities in an organism's preferred environment , causing population fragmentation...
has restricted species dispersal
Biological dispersal
Biological dispersal refers to species movement away from an existing population or away from the parent organism. Through simply moving from one habitat patch to another, the dispersal of an individual has consequences not only for individual fitness, but also for population dynamics, population...
as it depends on continuous canopy cover to move from tree to tree.