Rattus exulans

In ricefields, the presence of rats is indicated by cut tillers, scattered grains and leaves on the ground, foot prints and runways. In coconut groves, fallen nuts with holes are seen. In fruits and root crops, gnawed holes made by the rats’ sharp incisors are the common signs of damage. It is difficult to differentiate rodent species merely by the damage they cause. Faeces are not reliable indicators of species because of their sizes overlap with other rodent species (Atkinson and Towns, 2005;Shiels et al., 2014). R. exulans faeces generally range from 6.4-9.0 mm in length (Atkinson and Towns, 2005).
R. exulans often has dark-coloured upper sides of hind feet which is unlike R. rattus, R. norvegicus, and Mus musculus, which all have uniformly colouring over whole feet (Atkinson and Towns, 2005).
If more than one rodent species is suspected to be in the habitat or area, traps (snap traps and live traps) can be used to catch rats for proper identification. In the Philippines, the trapping period may be extended (more than three nights) to catch the dominant species (R. rattus mindanensis, R. argentiventer or R. norvegicus) during the first nights of trapping, before catching R. exulans. A similar pattern of R. rattus dominance during the first trap nights, and R. exulans only captured on nights after the first two nights, has been also found in Hawaii (Shiels, 2010).
For regular monitoring of R. exulans populations, use of tracking tiles (made of vinyl or other material) are common, where mimeographing ink is painted on half of the area of each tile and laid along the path of the rats (Sanchez and Benigno, 1985) or otherwise in the habitat of interest (Shiels, 2010).