Table-Sharers: Rodents of the Ricefields

Groves (1984a) has surveyed a number of murid rodents that appear to have been introduced into Island Southeast Asia and are closely tied to wet rice landscapes. These animals are “commensal”, meaning “sharing the same table”, that is they live among humans and in their cultural landscape. Mus caroli, Mus cervicolor (Map 2) and Rattus argentiventer are widely distributed in Mainland Southeast Asia north of the Malay Peninsula; their distributions are spotty in the archipelago and invariably restricted to wet rice growing areas. If the pests travelled initially with the padi then a Burma/Thailand/Vietnam centre for the rice complex is suggested; if they came afterwards then a general importance for this area in later rice trading is indicated.

One species whose distribution does extend into the Mahanadi delta region, and so might have travelled with the water-buffalo from India, is the lesser bandicoot-rat, Bandicota bengalensis, a noted ricefield pest in Indonesia (Map 3). It is especially significant that, in Thailand, Indochina and most of Burma, it is replaced by an ecologically equivalent species, B. savilei, which did not get introduced into the archipelago.

Map 2. Distribution of Mus cervicolor.

Map 2. Distribution of Mus cervicolor.

Solid dots represent approximate locations recorded. From Groves (1984b).

Map 3. Distribution of Bandicota bengalensis.

Map 3. Distribution of Bandicota bengalensis.

Diagonal lines indicate mainland distribution; solid dots recorded locations in Sundaland. From Groves (1984b).

Two somewhat unexpected ricefield pests in Indonesia are Mus dunni, a small mouse indigenous to northwestern India, and Rattus nitidus, indigenous to Nepal. Surely no explanation to do with early rice expansion will suffice in these cases.

Finally, among the agricultural pests must be mentioned the Pacific rat, Rattus exulans, which is wild in both Mainland and Island Southeast Asia. Smaller than the worldwide commensal rats R. rattus (black rat, roof rat) and R. norvegicus (brown rat, ship rat, Norway rat), this was the only species occurring on the Pacific islands, where it was commonly eaten, in pre-European contact times. Unfortunately its very versatility precludes us from associating it with any particular subsistence mode.