Micromammals are notoriously difficult to observe because of their small size, and their cryptic, and often nocturnal lifestyle (Halle and Stenseth, 2001). Therefore, live trapping methods are commonly employed to determine distribution, estimate population densities, and infer animal activity (Gentry et al., 1965; Vickery and Rivest, 1991; Atsalis, 2000; Caro et al., 2001; Radespiel et al., 2001; Schwab and Ganzhorn, 2004; Halle 2006; Prugh and Brashares, 2010). Because trapping is an indirect method of studying animal behavior, results should be interpreted cautiously (Prugh and Brashares, 2010), and should take into account a number of biotic and abiotic factors (Prugh and Golden, 2014). Factors that can affect activity and therefore capture rates of small mammals include predator behavior (Hilton et al., 1999; Michalski and Norris, 2011; Cozzi et al., 2012; Falcy and Danielson, 2013), and the temporal and spatial availability of food and shelter (Kotler et al., 1993; Caro et al., 2001; Davidson and Morris, 2001; Kelt et al., 2004). In addition, possible affects of season, temperature, rainfall, and the lunar cycle must be considered (Kotler et al., 1991; Daly et al., 1992; Sutherland and Predavec, 1999; Stokes et al., 2001; Michalski and Norris, 2011; Maestro and Marinho,2014; Prugh and Golden, 2014).
Small mammals may reduce activity during extreme temperatures (either hot or cold) due to thermoregulatory demands (Gentry and Odum, 1957; Vickery and Bider, 1981; Falcy and Danielson, 2013). Cold is especially dangerous to small mammals because of their susceptibility to hypothermia. This might explain why old-field mice (Peromyscus polionotus) were less frequently captured during cold than warm nights (Gentry and Odum, 1957), and why common voles (Microtus arvalis) reduced activity with decreasing temperature (Lehman and Sommersberg, 1980). Some small mammals (Lyman, 1983), including small primates such as mouse lemurs (Microcebus) and dwarf lemurs (Cheirogaleus), may become completely inactive for periods of time, undergoing hibernation (dwarf lemurs) or periods of torpor (Genin et al., 2005; Blanco and Godfrey, 2014). Mouse lemurs may be in an inactive, torpid state for days, weeks, or even months during the austral winter (Ortmann et al., 1997; Schmid, 2000).