Daily activity patterns in the giant root rat (Tachyoryctes macrocephalus), a fossorial rodent from the Afro‐alpine zone of the Bale Mountains, Ethiopia

Abstract

AbstractRodents adjust their activity to environmental conditions. The adjustment can be especially pronounced in climatically challenging environments. We studied activity patterns in the free‐living giant root rat (Tachyoryctes macrocephalus), a large fossorial rodent endemic to the Afro‐alpine ecosystem of the Bale Mountains, Ethiopia, by means of radio telemetry. We radio‐tracked 17 adults during two periods of a dry season differing in temperature and food supply. In both periods, root rats spent a large part of the day (around 79%) in their underground nests. The proportion of time the animals were active aboveground decreased from 6.9 to 3.8% between the early and late dry season, which contradicts our prediction that aboveground activity would increase under lower food supply. We propose that there are thermoregulation advantages of prolonged aboveground activity during warm hours in the colder early dry season. In both periods, the root rats displayed diurnal activity with a unimodal pattern positively related to the temperature at the soil surface. Unlike in some other burrowing rodents, there was no tendency to decrease activity in the warmest part of the day even in the relatively warm late dry season.