699.

Philippine Forest Rat

Rattus everetti

French: Rat d’'Everett / German: Philippinen-Ratte / Spanish: Rata de bosque de Filipinas

Other common names: Common Philippine Forest Rat

Taxonomy. Mus everetti Gunther, 1879,

northern Mindanao Island, Philippines.

Rattus everetti clusters with Limnomys and

Tarsomys, making Rattus paraphyletic, but

in other studies, it was found to be closely

related to R. exulans . Although additional research is still needed,it could be placed in a separate genus at some point, or Limnomys and Tarsomys will be included within Rattus . There is substantial geographical variation of R. everett among islands that should be examined.

Distribution. Philippines, including Luzon, Mindoro, Marinduque, Burias, Ticao, Sibuyan, Catanduanes, Panay, Samar, Calicoan, Leyte, Maripipi, Biliran, Bohol, Dinagat, Siargao, Camiguin, Mindanao, and Basilan Is.

Descriptive notes. Head—body 207-237 mm, tail 181-244 mm, ear 25-29 mm, hindfoot 42-50 mm; weight 320-390 g. The Philippine Forest Rat is large, distinctive, and variable, with harsh and somewhat spiny pelage. Dorsum is dark brown, with light black guard hairs; underfur is gray; and pelage is usually lighter on sides and head. Venter is white, with yellowish or orangish hue. Feet are dark dorsally and usually pale ventrally. Ears are similar in color to dorsum. Tail is more than 100% of head-body length, black until about the lower one-half that is white, and tip is usually stained with dirt. Skull has globose bullae and heavy supraorbital and temporal crests. Lice (Polyplax spinulosa), fleas (Chirodiscoides caviae), and mites (Laelaps nuttali) have been recorded on the Philippine Forest Rat. There are four pairs of mammae: two pectoral and two inguinal pairs. Chromosomal complement is 2n = 42, FN = 64-70.

Habitat. Primary and disturbed lowland, montane, and mossy forest, including scrubby areas close to forest, at elevations up to 2400 m. The Philippine Forest Rat can also be found in agricultural and disturbed areas commonly. It might have been a disturbance specialist before human colonization, which may explain abundance. Relative abundance seems to increase with elevation on Mindanao, but Philippine Forest Rats are more common in lowlands and less common at higher elevations on Luzon.

Food and Feeding. The Philippine Forest Rat commonly eats seeds, fruits, invertebrates, and crops such as sweet potatoes, which could make it a pest.

Breeding. Females have been pregnantfor the first time at weights of ¢.200 g. An average of 3-7 embryos (range 2-5) was found in a sample of eight females. Males have large scrotums (15 mm x 28 mm).

Activity patterns. Philippine Forest Rats are nocturnal and somewhatcrepuscular, feeding mainly at night. They are arboreal and terrestrial when foraging.

Movements, Home range and Social organization. Density of Philippine Forest Rats was 1-2 ind/ha at Mount Isarog on Luzon. They were also reported to have moved several hundred meters between captures and had home ranges of up to 1 ha.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Philippine Forest Rat is abundant throughoutits distribution and is found in many protected areasthroughout the Philippines. There are no major threats, and it is more competitively dominant than the commonly introduced Rattus —the Roof Rat ( R. rattus), the Brown Rat ( R. norvegicus), and the Pacific Tat ( R. exulans)—although they are hunted for food on Mindanao.

Bibliography. Alviola et al. (2011), Balete, Alviola et al. (2011), Balete, Quidlat & Ibanez (2006), Duya, Alviola et al. (2007), Duya, Duya et al. (2011), Heaney & Rabor (1982), Heaney, Alviola et al. (2016), Heaney, Balete, Dollar et al. (1998), Heaney, Balete & Rickart (2016), Heaney, Gonzales et al. (1991), Luyon & Salibay (2007), Musser & Carleton (2005), Musser & Heaney (1992), Rabor (1955), Rickart, Balete & Heaney (2007), Rickart, Heaney, Balete et al. (2013), Rickart, Heaney, Heidman & Utzurrum (1993), Rickart, Heaney & Utzurrum (1991), Rowe et al. (2011), Salibay & Luyon (2008), Steppan & Schenk (2017).