Despite its appearance and name, the moonrat (Echinosorex gymnura) is not closely related to rats or other rodents. This Southeast Asian insectivore is classified under Order Erinaceomorpha, the same group which includes hedgehogs and gymnures, that feed primarily on insects as well as other arthropods. In Peninsular Malaysia, the moonrat is generally black and white in colour, with the face covered by white fur and marked by three prominent black patches. Another subspecies, Echinosorex gymnura alba is found in Borneo and appears to be generally white with only a sparse scattering of black hairs, although those from western Borneo have more black hairs than those from the eastern region. The three black patches on the head of E. gymnura are located as follows: one patch between the ears and a patch around each eye. The tail is blackish along its first half and white at the tip, and appears scaly with sparse hairs.
The moonrat has a long, mobile nose which has a groove on its underside, from the tip to a point between the upper incisors. Its body is long and narrow and the canine teeth are usually larger than the adjacent teeth. Commonly, it weighs up to 1.4 kg and its body is 26 to 45 cm in length with a 17 to 29 cm long tail (Britannica, 2005).
The moonrat uses its teeth and long snout to seek out earthworms and arthropods by scratching and probing in rotten trunks and leaf litter. Its sensitive whiskers and snout tip are used for the detection of prey. This solitary species flees immediately when disturbed, but emits ‘hiss-puffs’ and low roars followed by head swinging from side to side as defensive acts during captivity. An odour of rotten onions or ammonia envelops the moonrat and this is caused by secretions from its paired anal glands (Britannica, 2005). During movement, the moonrat elevates its body high off the ground, tending to raise its snout and elongating its posture; this is common in other mammals (Eisenberg, 1963; Eisenberg & Gould, 1970). In an aquatic environment, the moonrat uses its tail as a rudder by swishing it from side to side. It keeps its chin above water, but when submerged, it can close its nostrils.
The main diet of the moonrat includes terrestrial and aquatic invertebrates. For instance, Gould (1978) recorded the presence of cockroaches, beetles, millipedes, centipedes, spiders, molluscs, crabs, earthworms and arthropods from an examination of the stomach contents of 20 moonrats. A diet that includes aquatic invertebrates suggests its swimming ability and preference of feeding in streams (Gould, 1978). Observations by Gould (1978) in an oil palm plantation resulted in the discovery of two moonrats with intense orange stain on the fur of their heads, suggesting consumption of oil palm fruit. During captivity, it has been observed that this species also preferred other fruits, including bananas and apples (Lim, 1967).
Although this species is active both during the day and night (Harrison & Medway, 1969), it is generally more active at night. This species tends not to wander far from streams and usually rests in hollow rotting tree trunks on the ground, under tree roots or in-ground cavities (Britannica, 2005). Dens of the moonrat consist of either burrows or rock crevices on the forest floor and are usually marked by secretions. In mangrove forests, nipa palms serve as dens.
Its natural distribution includes the Malay Peninsula, Borneo, Sumatra and also the island of Labuan. It prefers primary and secondary lowland forests, moist areas such as mangrove forests and swamp forest, and also rubber plantations located next to rainforests.
According to Cassola (2016), E. gymnura is listed in the International Union for Conservation of Nature (IUCN) Red List as Least Concern (LC). Although the moonrat does face threats such as forest loss due to conversion to oil palm plantations and other land development projects, it is relatively adaptable to the changes. Despite its LC status, further studies still need to be carried out to ensure its ability to survive in oil palm plantations and conservation measures need to be implemented to create a sustainable environment for this species to continue to exist.
