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

Abstract

Rodents 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.

Day and night in the subterranean: measuring daily activity patterns of subterranean rodents (Ctenomys aff. knighti) using bio-logging

“…However, recording of activity in the field constitutes a logistical challenge (Halle and Stenseth, 2000; Dominoni et al , 2017), particularly for subterranean rodents, with varying degrees of underground and aboveground activity. While most studies of activity patterns in free-living subterranean/fossorial mammals have been conducted with mole rats from Africa and Asia (Nevo et al , 1982; Ben-Shlomo et al , 1995; Lovegrove and Muir, 1996; Riccio and Goldman, 2000; Oosthuizen et al , 2003; Sklíba et al , 2007; Vlasatá et al , 2017), caviomorph subterranean/fossorial species from South America have also added important insights to this comparative study (Kenagy et al , 2002a, 2002b; Rezende et al , 2003; Tomotani et al , 2012; Estevan et al , 2016). In particular, the influence of ambient temperature on the surface activity of subterranean/fossorial rodents has been well studied in the South American degu (Kenagy et al ., 2002a, 2002b) and coruro (Rezende et al ., 2003).…”

Implications of present ground temperatures and relict stone stripes in the Ethiopian Highlands for the palaeoclimate of the tropics

“…Gottelli et al, 1994), giant mole-rat (Tachyoryctes macrocephalus) (e.g. Vlasatá et al, 2017), and mountain nyala (Tragelaphus buxtoni) that are restricted to the Ethiopian Highlands (Miehe and Miehe, 1994). Since these endemic species mainly populate the upper valleys and Sanetti Plateau today, palaeoclimatic and -environmental changes like a severe cooling, expansion of the ice cover and periglacial area as well as depression of altitudinal vegetation belts must have directly affected their habitat and are therefore also of relevance in a geoecological context.…”

Sazonalidade dos padrões diários de atividade de superfí­cie em um roedor subterrâneo, o tuco-tuco

“…Em relação aos padrões temporais de atividade, estudos de animais de seis das oito linhagens, em campo ou laboratório, mostraram variações inter e intraespecíficas no horário do dia em que ocorria atividade (Bathyergidae: Jarvis, 1973;Lovegrove et al, 1993;Lovegrove & Muir, 1996;Šklíba et al, 2007;Ctenomyidae: Cutrera et al, 2006;Estevan et al, 2016;Geomyidae: Gettinger, 1984;Benedix Jr, 1994;Octodontidae: Urrejola et al, 2005;Rhyzominae: Jarvis, 1973;Vlasatá et al, 2017;Spalacinae: Nevo et al, 1982;Ben-Shlomo et al, 1995). Apesar disso, bathyergídeos e spalacinos estudados em laboratório apresentaram ritmo de atividade endógeno quando mantidos em condições constantes (Lovegrove et al, 1993;Ben-Shlomo et al, 1995;Lovegrove & Muir, 1996).…”

“…• Câmeras sensíveis a movimento. (Valentinuzzi et al, 2009;Tachinardi et al, 2014 (Jarvis, 1973;Gettinger, 1984;Urrejola et al, 2005;Estevan et al, 2016;Vlasatá et al, 2017). Entretanto, as tentativas anteriores de registro da atividade dos tuco-tucos com rádio-telemetria, realizadas pelo nosso grupo (Tomotani, 2011) (Collins et al, 2015;Dominoni et al, 2017) e se mostrou mais adequado para o registro da atividade dos tuco-tucos.…”

“…Ao mesmo tempo, pelo fato dos tuco-tucos serem subterrâneos, poderia ser atividades com a mudança das temperaturas em diferentes níveis abaixo do solo (Kenagy, 1973;Rado et al, 1993). Mesmo assim, isso não elimina a possibilidade de que esses animais também são influenciados pela temperatura na superfície (Rado et al, 1993;Rezende et al, 2003;Vlasatá et al, 2017).…”