Northern tree shrews make 8 distinct sounds (Fuchs and Corbach-Sohle, 2009). Of these 4 can be associated with functional categories that are described by Binz and Zimmermann (1989): alarm, attention, contact, and defense. Tree shrew noises can range from 0.4 to 20 kHz. The structure of the sounds depend on the status and motivation of the individuals; their pitch increases with fear and decreases in pitch (or increases in frequency) with increased aggression (Kirchhof et al., 2001). Kirchhof et al. (2001) also note that tree shrews do not use ultrasonic localisations. Tree shrews use scent marking to indicate boundaries of their territories (Fuchs and Corbach-Sohle, 2009).
Communication Channels: visual ; tactile ; acoustic ; chemical
Other Communication Modes: scent marks
Perception Channels: visual ; tactile ; acoustic ; chemical
IUCN (2012) describe northern tree shrews as the Least Concern status. They have a population that is stable, and they are common throughout their range. IUCN (2012) lists them as least concern because of their wide range, abundance, ability to tolerate disturbance, and they are present in many protected areas.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
Northern tree shrews have well defined, sharp teeth. Should they feel threatened these could be used as a defense mechanism. It is highly unlikely that these animals would attack a human but a small possibility. Otherwise there are no known negative economic effects of northern tree shrews.
Negative Impacts: injures humans (bites or stings)
There are no known positive economic effects of northern tree shrews.
While the main food source of northern tree shrews is insects, they also eat fruit to supplement their diet. It could be inferred that they play a role in the seed dispersal of fruit bearing trees.
Ecosystem Impact: disperses seeds
Northern tree shrews are predominantly insectivorous, but eat fruits to obtain extra nutrients and calories to their high protein diet (Fuchs and Corbach-Sohle, 2009).
Tree shrews do not absorb much water from their food and they are unable to go more than 1 day without free water (Fuchs and Corbach-Sohle, 2009)
Animal Foods: eggs; insects
Plant Foods: fruit
Primary Diet: carnivore (Insectivore ); herbivore (Frugivore ); omnivore
Northern tree shrews are found in South East Asia (IUCN Red List, 2012). The IUCN (2012) specifies that they are native to Bangladesh, Bhutan, Cambodia, China, Lao People's Democratic Republic, Malaysia, Myanmar, Thailand and Vietnam.
Biogeographic Regions: oriental (Native )
Northern tree shrews inhabit a variety of forest habitats. They live in tropical and subtropical areas, which are usually moist environments (IUCN, 2012). They have also been recorded in shrub lands and artificial plantations and rural gardens. IUCN (2012) reports 3000 meters as the highest known elevation for tree shrew, recorded in China. Tree shrews inhabit areas about 25 degrees Celsius, with at least 45 to 50% humidity (Fuchs and Corbach-Sohle, 2009).
Range elevation: 0 to 3,000 m.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: forest
Captive northern tree shrews live 9 to 12 years (Fuchs and Corbach-Sohle, 2009). The lifespan of northern tree shrews in the wild is currently unknown.
Range lifespan
Status: captivity: 12 (high) hours.
Typical lifespan
Status: captivity: 9 to 12 years.
Northern tree shrews have greyish, olive fur with an elongated snout (Smithsonian National Zoological Park, 2012). The dental formula of the Tupaiidae is incisors 2/3, canines 1/1, pre-molars 3/3, and molars 3/3 (Fuchs and Corbach-Sohle, 2009). Northern tree shrews are moderately sexually dimorphic (Collins and Tsang, 1987; Schehka et al., 2007). Male tree shrews have a larger body size and ring of white hair around the eye compared to females. Males also have a broader skull than the females (Collins and Tsang, 1987).
Fuchs and Corbach-Sohle (2009) describe the difficulty in determining the sex of young tree shrews. As pups the external genitalia of both males and females look alike. Males have a slender and elongate penis, which is posterior to scrotal testes, which can be retracted into the abdominal cavity if the individual is stressed. In females the clitoris is greatly elongated and grooved on its ventral surface. In neonatal shrews the urethra opens together with the vagina as a single opening at the base of the clitoris; this is what looks like the males penis in young female tree shrews. However the clitoris does not have a tubular sheath like the penis.
Northern tree shrews have a mass of approximately 50 to 270 grams, Head to Body Length of 12 to 21 cm and a tail length ranging from 14 to 20 cm, usually close to the length of their body (Fuchs and Corbach-Sohle, 2009). Shrew body temperature has been described, ranging from about 35 degrees Celsius to 40 degrees Celsius; this 5 degree difference is much larger than most endothermic animals (Fuchs and Corbach-Sohle, 2009).
Range mass: 50 to 270 g.
Range length: 26 to 41 cm.
Sexual Dimorphism: male larger; sexes colored or patterned differently; sexes shaped differently
Other Physical Features: endothermic ; bilateral symmetry
It has been noted that tree shrews will react to predation risk (Schehka et al., 2007; Fuchs and Corbach-Sohle, 2009). They will display defensively to a threat, specifically baring teeth and making high pitched, loud vocalizations (Schehka, 2007). Specific predators of northern tree shrews are not specificed. However, due to their size and behavior possible predators could include, large birds of prey, snakes, and potentially some carnivorous mammals.
Anti-predator Adaptations: aposematic ; cryptic
Northern tree shrews have a monogamous mating system (Collins and Tsang, 1987). Introductions between a mating pair are possibly the hardest part of breeding for northern tree shrews. Copulation can occur within a few hours if the female accepts the male (Fuchs and Corbach-Sohle, 2009). However, they usually use more aggressive behaviors. Fuchs and Corbach-Sohle (2009) suggest two explanations: first, that the individuals merely don't like each other, and second that to mate one animal has to enter the others territory. Northern tree shrews, male or female, will defend their territory against intruders. If the couple can overcome this they will form a stable breeding pair and continue to breed together. Females have an 8 to 12 day estrous cycle. Ovulation is thought to be induced by copulation (Martin, 1990)
Mating System: monogamous
Under natural and artificial conditions Fuchs and Corbach-Sohle (2009) observed that breeding can occur at any time of the year; no peak periods were found. Males and females become sexually reproductive around the same time. Males will be active between four and five months and females can give birth to their first litter at approximately 4 months old. Northern tree shrews have a litter size of 1 to 5 young. The gestation period occurs for approximately 41 to 45 days and females give birth to hairless, altricial young. Pups ears open at around 10 days and their eyes open at approximately 20 days after birth. Female young tend to be heavier than males, but on average young will have a birth mass of 6 to 10 grams (Fuchs and Corbach-Sohle, 2009). Young will drink their mothers milk until they are around 35 days old when they wean off the liquid diet. Northern tree shrews reach puberty at about 2 months old and can be separated from their mother at about 50 to 60 days (Fuchs and Corbach-Sohle, 2009). Older mothers may have problems with infertility, still birth, cannibalism or abortion. These problems can also occur in females that are stressed, which is likely in tree shrews as they are highly susceptible to stressors (Fuchs and Corbach-Sohle, 2009).
Breeding interval: Northern tree shrews breed continuously throughout the year.
Breeding season: Northern tree shrews breed continuously and do not have a seasonal breeding peak.
Range number of offspring: 1 to 5.
Range gestation period: 41 to 45 days.
Average weaning age: 35 days.
Range time to independence: 50 to 60 days.
Range age at sexual or reproductive maturity (female): 4 to 5 months.
Range age at sexual or reproductive maturity (male): 4 to 5 months.
Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; induced ovulation ; viviparous
Immediately after birth the mother will nurse her pups and thereafter only return to feed her young once every 48 hours (Fuchs and Corbach-Sohle, 2009). They receive approximately 5 to 10 milliliters of milk, with a relatively high fat content of about 25%. Pups consume this amount of milk in approximately 2 to 10 minutes. As a result pups have less than 2 hours contact with their mother during the 30 to 35 day period. Martin (1990) described that as the lowest mother to infant contact and smallest parental investment for viviparous mammals described thus far. Males are not involved in parental care after copulation (Fuchs and Corbach-Sohle (2009).
Parental Investment: altricial ; female parental care ; pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female); pre-independence (Provisioning: Female); post-independence association with parents
The northern treeshrew (Tupaia belangeri) is a treeshrew species native to Southeast Asia.[1]
In 1841, the German zoologist Johann Andreas Wagner first used the specific name Cladobates belangeri for treeshrews that had been collected in Pegu during a French expedition to Southeast Asia. These specimens were described by Isidore Geoffroy Saint-Hilaire in 1834 in whose opinion they did not differ sufficiently from Tupaia tana to assign a specific rank.[2][3]
Results of a telemetry study involving northern treeshrews showed that their body temperature varies from 35 °C (95 °F) during the night to 40 °C (104 °F) during the day. This difference is larger than in other endotherms, and indicates that the circadian rhythms of body temperature and locomotor activity are synchronized.[4]
Adults weigh 0.2 kg (0.44 lb). The maximum longevity of the northern treeshrew is 11 years.
Complete mitochondrial genome data support the hypothesis of a closer phylogenetic relationship of Tupaia to rabbits than to primates.[5] This is however disputed by the more recent full genome sequencing data that places the species closer to primates (divergence ~90.9 million years ago) than to lagomorphs and rodents (~96.4 Million years ago).[6]
The northern treeshrew has attained growing interest for use as a medical model. In 2002, an article was published describing that its primary hepatocytes could be used as a model for studying the Hepatitis C virus, which is a major cause of chronic hepatitis worldwide.[7] It was also used in studies on the development of photo reception,[8] investigation of retinal cones,[9] and refractive state and ocular component dimensions of the eye.[10] Many studies have been conducted regarding eye structure, development, and vision using the northern treeshrew model because of the similarity to human eye structure and sight that is uncharacteristic of conventional small lab animals, such as rodents.[11]
The northern treeshrew (Tupaia belangeri) is a treeshrew species native to Southeast Asia.
In 1841, the German zoologist Johann Andreas Wagner first used the specific name Cladobates belangeri for treeshrews that had been collected in Pegu during a French expedition to Southeast Asia. These specimens were described by Isidore Geoffroy Saint-Hilaire in 1834 in whose opinion they did not differ sufficiently from Tupaia tana to assign a specific rank.
