“…Unlike migratory birds that must feed throughout the winter to survive, all species of migratory tree bats are heterothermic endotherms capable of extended periods of deep, facultative, energy-saving torpor in response to unfavorable conditions, such as low air temperatures and lack of insect prey (Barbour and Davis 1969, Genoud 1993, McGuire and Guglielmo 2009; several species of tree bats are known or suspected to hibernate after migrating to their wintering grounds (Davis 1970a, Baker 1978, Mormann and Robbins 2007, Dietz et al 2009, Perry et al 2010. Additional distinctive natural history characteristics of most temperate-zone bats, such as ubiquitous autumn/winter mating and disparate distributions and behaviors of the sexes during spring through early summer (Racey 1982, Senior et al 2005, Weller et al 2009, van Toor et al 2011, Angell et al 2013, make it likely that migration behaviors of bats evolved in ways that could differ dramatically from those of many other types of migratory animals (Fleming and Eby 2003). Recent studies of migratory tree bats have revealed intriguing evidence that they migrate differently than birds and perhaps other bats, such as feeding en route rather than strictly during stopovers to supplement endogenous energy stores, and using a torpor-assisted migration strategy (McGuire et al 2011, Voigt et al 2012b.…”