The bush Karoo rat Otomys unisulcatus on the Cape West coast

Abstract

In the Postberg Nature Reserve, coastal Western Cape Province, bush Karoo rats Otomys unisulcatus build dome-shaped stick shelters or lodges, with a mean height of 1,45 m and a mean volume of 0,61 m³, usually with Exomis microphylla var. axyrioides as a supporting shrub. Sticks and twigs utilized are from 10 to 517 mm long, 3,5 mm thick, and with a mean length up to 117 mm per lodge, interwoven to form intricate structures. These are criss-crossed with passages and contain two nests and two latrines each. More than 13 000 sticks can be used to build a lodge; this involves travelling total distances of up to 16,5 km to gather building material. A network of paths interconnects lodges and leads to shrubs providing sticks and food. Most lodges are inhabited by one or two individuals. The species is diurnal and crepuscular.