The common treeshrew is one of the largest among treeshrews. Average body length is between 16 and 21cm (6.3 and 8.3in), and average weight is around 190 g, with varying colours of reddish-brown, greyish or black upper parts and whitish belly. Its long, bushy tail is dark greyish-brown and almost reaches the length of the body. The paws are bare with sharp nails, and with a naked patch of skin above its long nose. Both sexes are similar. The animal has a head and body length of 13–21cm and a tail length of 12–20cm.[2] The common treeshrew usually has a white, pale stripe on each shoulder.
The two subspecies are T. g. longipes and T. g. salatana, with T. g. longipes being duller in color than T. g. salatana. The underparts of T. g. longipes are dull buff to reddish-buff, and the underside of the tail is greyish. The underparts and underside of the tail are dark reddish in T. g. salatana. Similar species are Tupaia splendidula and Tupaia montana.
Distribution and habitat
Common treeshrews occur south of about 10°N latitude in southern Thailand through mainland Malaysia and adjacent coastal islands to Singapore. They inhabit protected areas, including the Pasoh Forest Reserve on the Malay Peninsula and Krau Wildlife Reserve.[1] In Indonesia, they are found on the islands of Siberut, Batu, Sumatra, Java, Bangka, Riau, Lingga and Anambas.[3] Usually they are found in primary dipterocarp forest, but are tolerant to some degree of habitat modification. They have also been recorded from secondary forest, plantations, fruit orchards, and trees near housing areas.[4]
Common treeshrews are probably present throughout the lowlands and hills up to 1,100m (3,600ft) in the Kelabit Highlands of Borneo. The subspecies T. g. longipes occurs in the north of Borneo, in Sarawak, and in East Kalimantan, including Sabah. The subspecies T. g. salatana occurs in the south of Rajang River and Kayan River in Borneo.[5]
Ecology and behavior
Common treeshrews are active during the day, and forage for food alone or in pairs, mainly on the ground, among shrubs and tree holes. They feed on fruits, seeds, leaves, and insects, especially ants and spiders.[6] They are also reported to catch lizards.
They are very agile in climbing both large vertical tree trunks and bushes, and occasionally jump from stems of a young tree to that of another as much as 60cm (24in) away. Their climbing is concentrated in lower heights. They frequently scent-mark their territories by chest and anogenital rubbing with a secretion from glands on chest and scrotum. Adult males are more secretory than females and juveniles. In the Bukit Timah Nature Reserve, mean home ranges of adult males were estimated at 10,174m2 (109,510sqft), of adult females at 8,809m2 (94,820sqft), of juvenile males at 7,527m2 (81,020sqft), and of juvenile females at 7,255m2 (78,090sqft), with partial overlaps between male and female ranges varying from 0.4% to 56.8%. Home ranges of adult residents of the same sex overlap to a lesser degree than those of opposite sexes. A male's range may include the ranges of two or three females. A high overlap between ranges of one adult male and one adult female indicates they form a stable pair. Juvenile ranges of either sex adjoin or overlap with ranges of adults, suggesting the juveniles are family members. Individuals of the same sex are involved in aggressive territorial chases.[7]
Juvenile males depart from their family's territory sooner than juvenile females.[6]
Reproduction
Both sexes of common treeshrews are sexually mature at the age of about three months. In captivity, females give birth for the first time at the age of about 4.5 mo, usually in February. A postpartum oestrus results in more births in April. Their oestrus cycle is eight to 39 days, and the gestation period lasts 40 to 52 days, after which a litter of one to three individuals is born. The newborn offspring weigh about 10 to 12 grams. Females suckle their young every other day, and neglect their young as long as possible. They would not even be able to identify their own young if they did not mark them with the scent produced from glands in their sternum and abdomen. Juveniles leave the nest between 25 and 35 days of age. Longevity of a captive common treeshrew has been recorded as 12 yr and 5 mo.[6]
From October to December, common treeshrews are reproductively inactive.[7] The mating season starts at the onset of the monsoon season in December and lasts until February. Oestrus and proestrus behavior is characterized by adult males pursuing adult females. Males emit chattering, and appear to be extremely excited. They also chase each other and fight. Females do not actively choose a partner among the male participants of chases. The dominant male gains access to females.[8]
In tropical rainforest habitats in West Malaysia, population density varies from two to five animals per hectare. Their annual breeding coincides with the abundance of invertebrates after the dry season. Their main reproductive period is between February and June, and their litter size is invariably two. Some females breed more than once a season, and the age at first pregnancy is seven months. The main period of emigration or mortality of young is during the breeding period or monsoon.[9]
Taxonomic status
The species was first described in February 1820 by the French explorers Pierre-Médard Diard and Alfred Duvaucel in their jointly written article "Sur une nouvelle espèce de Sorex — Sorex Glis", which is preceded by an illustration. They observed specimens in Penang and Singapore, and considered them a species of Sorex, and not as a new genus.[10] Between 1821 and 1940, several zoologists described the species from other areas. The species still retains many forms of uncertain rank and validity, and is pending a detailed study. Some forms were formerly considered synonyms of Tupaia glis; some were elevated to species level. Synonyms include:[3]
Common treeshrews are threatened due to deforestation and ensuing human activities in agriculture (for example, using trenchers to dig ditches), plantations, and commercial logging. Moreover, other pressures, such as hunting for food and sport, can create pressure to the species.[3]
As a model organism
Tupaia glis is used by researchers as animal models for human diseases because of their close relationship to primates, and their well-developed senses of vision and hearing. Research studies have included hepatitis.[12] Another instance has been documented where an individual of Tupaia glis developed breast cancer.[13]
Related Research Articles
The treeshrews are small mammals native to the tropical forests of South and Southeast Asia. They make up the entire order Scandentia, which split into two families: the Tupaiidae, and the Ptilocercidae.
The Arctic shrew, also known as the blackback shrew or saddlebacked shrew, is a medium-sized shrew found in Canada and the northern United States. Separate species status has been proposed for the maritime shrew which is found in New Brunswick and Nova Scotia and had been considered to be a subspecies of the Arctic shrew. The tundra shrew was formerly considered to be a subspecies of the Arctic shrew.
The vagrant shrew, also known as the wandering shrew, is a medium-sized North American shrew. At one time, the montane shrew and the Orizaba long-tailed shrew were considered to belong to the same species.
The Madras treeshrew, also known as the Indian treeshrew, is a species of treeshrew in the monotypic genus Anathana found in the hill forests of central and southern India. The genus name is derived from the Tamil name of moongil anathaan and the species name is after Sir Walter Elliot of the Indian Civil Services in Madras.
The northern treeshrew is a treeshrew species native to Southeast Asia.
The mountain treeshrew is a treeshrew species within the Tupaiidae. It is endemic to Borneo and inhabits montane forests in Sarawak and Sabah, Malaysia, and Kalimantan, Indonesia.
The ruddy treeshrew is a treeshrew species in the family Tupaiidae. It is endemic to Borneo, the Natuna Islands and the Anambas Islands.
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The Mindanao treeshrew, also called the Philippine tree shrew, is a species of treeshrew endemic to the Mindanao region in the Philippines. It was formerly considered the only member of the genus Urogale, but that genus was merged into Tupaia when the species was found to nest within the latter genus in a molecular phylogeny. The scientific name commemorates British colonial administrator and zoological collector Alfred Hart Everett.
Tupaia is a treeshrew genus in the family Tupaiidae that was first described by Thomas Stamford Raffles in 1821. The name of this genus derives from the Malay word tupai meaning squirrel or small animal resembling a squirrel.
Tupaiidae is one of two families of treeshrews, the other family being Ptilocercidae. The family contains three living genera and 19 living species. The family name derives from tupai, the Malay word for treeshrew and also for squirrel which tupaiids superficially resemble. The former genus Urogale was disbanded in 2011 when the Mindanao treeshrew was moved to Tupaia based on a molecular phylogeny.
Tupaia miocenica is a fossil treeshrew from the Miocene of Thailand. Known only from a single tooth, an upper first or second molar, it is among the few known fossil treeshrews. With a length of 3.57 mm, the tooth is large for a treeshrew. At the back lingual corner, the tooth shows a small cusp, the hypocone, that is separated from the protocone in front of it by a narrow valley. The condition of the hypocone distinguishes this species from various other treeshrews. In addition, the presence of a well-developed but simple mesostyle is distinctive.
The Kalimantan treeshrew or southern large-footed treeshrew is a treeshrew species within the Tupaiidae family. It was originally described as a subspecies of Tupaia longipes and later listed as a junior synonym of Tupaia glis, before being returned to its subspecies status. It was raised up to species status in 2013. It is found on southern portion of the island of Borneo in Indonesia.
↑ Shepherd, Chris R.; Shepherd, Loretta Ann (2012). A Naturalist's Guide to the Mammals of Southeast Asia. Wiltshire, UK: John BeauFoy Publishing. p.16. ISBN978-1-906780-71-5.
↑ Langham, NPE (1982) Ecology of the Common Tree Shrew, Tupaia glis in Peninsular Malaysia. Journal of Zoology. Vol. 197 (3): 323–344 AbstractArchived 2012-04-04 at the Wayback Machine
↑ Diard, P.M., Duvaucel, A. (1820) "Sur une nouvelle espèce de Sorex — Sorex Glis". Asiatick researches, or, Transactions of the society instituted in Bengal, for inquiring into the history and antiquities, the arts, sciences, and literature of Asia, Volume 14. Bengal Military Orphans Press, 1822
↑ Rui Qi Yan, Jian Jia Su, Ding Rui Huang, You Chuan Gan, Chun Yang and Gua Hau Huang (1996). Human hepatitis B virus and hepatocellular carcinoma I. Experimental infection of tree shrews with hepatitis B virus. Journal of Cancer Research and Clinical Oncology, Volume 122, Number 5: 283–288. doi:10.1007/BF01261404
↑ Kuhn, H. and Schwaier, A. (1973). Implantation, early placentation, and the chronology of embryogenesis in Tupaia belangeri. Zeitschrift für Anatomie und Entwicklungsgeschichte 142(3): 315–340.
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