Tupaiidae Author Russell A. Mittermeier Author Don E. Wilson text 2018 2018-07-31 Lynx Edicions Barcelona Handbook of the Mammals of the World – Volume 8 Insectivores, Sloths and Colugos 242 269 book chapter http://doi.org/10.5281/zenodo.6779158 c0cd46f6-682c-4b64-8efa-ab19bef80cf3 978-84-16728-08-4 6779158 15. Slender Treeshrew Tupaia gracilis French: Toupaye gréle / German: Schlankspitzhérnchen / Spanish: Tupaya esbelta Taxonomy. Tupaia gracilis Thomas, 1893 , “Apoh River, base of Mount Batu Song, Baram district, East Sarawak,” Malaysia. This species is monotypic. Distribution. Borneo, except C highlands and the SE, also on nearby Banggi and Karimata Is; possibly on Belitung and Bangka Is. Descriptive notes. Head-body length 135— 150 mm, tail 155-180 mm, ear 11-14 mm, hindfoot 38-41 mm; weight c.70 g. The Slender Treeshrew is small, with long bushy tail. Dorsum is typically gray to brown agouti; venter is pale white to ivory. Skull is small and delicate. The Slender Treeshrew is easily confused with the Lesser Treeshrew (7. minor ) because they are similar in size and shape and distributed in low-elevation forests in Borneo. Habitat. L.ow-elevation pristine and logged forests up to elevations of ¢.1200 m. The slender Treeshrew is typically found on the ground; when in trees; it remains below 3 m from the ground. Food and Feeding. The Slender Treeshrew is a solitary forager and eats caterpillars, ants, grasshoppers, and other small insects from under surfaces ofleaves. Breeding. Although the Slender Treeshrew is solitary, polygynous systems were observed consisting of one male and two females. Females appear to have two offspring per litter. Juveniles were trapped in September, March, and May in Danum Valley, Sabah, and pregnant or lactating females were recorded in September, March, June, and August, implying year-round reproduction. Activity patterns. The Slender Treeshrew is diurnal and terrestrial. It is known to nest on or near the ground (maximum of 1-5 m off the forest floor) and use stumps, vines, and holesin trees in which to construct nests. Nest materials include fibers and leaves. Nests are not particularly well camouflaged, and of all species studied by L. H. Emmons in 2000, Slender Treeshrews had the most conspicuous nests. Movements, Home range and Social organization. The Slender Treeshrew forages on the ground and travels at an intermediate rate compared with other treeshrew species (c.1654 m/day traveled at a rate of 151 m/hour), despite its small size. It had the lowest density of the six-species measured by Emmons, averaging 13 ind/km?2. Home ranges of four Slender Treeshrews were c.7-15 ha (average 10-5 ha)—the largest home ranges compared with the other larger treeshrews that Emmons studied. The Slender Treeshrew appears to be territorial, and home ranges of males and females are not thought to overlap, with clear evidence of territorial displacement. Status and Conservation. CITES Appendix II. Classified as Least Concern on The [UCN Red List. The Slender Treeshrew is far less abundant than other treeshrew species on Borneo; the Lesser Treeshrew is nearly identical in size but found in much higher densities. Due to logging of lowland forests in Borneo, population trend of the Slender Treeshrew is decreasing, and it will probably require a change to a threatened category in the next 5-10 years. Bibliography. Emmons (2000).