The function of plants collected by bush Karoo rats (Otomys unisulcatus): Do dried up food plants represent stored food?

Abstract

Food storing to cope with food reduction during winter has been observed in many rodents in the northern hemisphere. Food storing could also be adaptive in semi-deserts of the southern hemisphere, which experience food-restricted dry seasons. We studied the function of dried food plants found at the stick lodges of bush Karoo rats in a semi-desert in South Africa. We performed 998 focal animal observations and monitored 12 lodges to record the fate of plant pieces carried back to the lodges. Collected plant species were eaten green (68 %), eaten as plantong (12 %), incorporated into the structure of the lodge (11 %), or their fate was unknown (9 %). Especially succulents carried back to the lodge dried out, forming what we refer to as plantong. This happened mainly in the food rich moist season. However, plantong was not stored from the moist to the dry season but was consumed within 6 ± 5 days. Bush Karoo rats readily ate plantong presented to them experimentally. We regard plantong as leftover from food freshly consumed at the lodge, but not as food collected in the moist season to be stored for later consumption during the dry season.