The Sheath-tailed bat Emballonura semicaudata semicaudata, is a small brown bat. Males have a forearm length of about 1.8 inches (in) (45 millimeters), and weigh approximately 0.2 ounces (oz) (5.7 grams [g]), and females are slightly larger in size and weight (Lemke 1986, p. 744; Nowak 1994, p. 91; Flannery 1995, p. 326; Uyehara and Wiles 2009, p. 5). The common name ‘‘sheath-tailed bat’’ refers to the nature of the tail attachment: the tail pierces the tail membrane, and its tip appears completely free on the upper surface of the membrane (Walker and Paradiso 1983, p. 209). All subspecies of the Pacific sheath-tailed bat appear to be cave-dependent, roosting during the day in a wide range of cave types, including overhanging cliffs, crevices, lava tubes, and limestone caves (Grant 1993, p. 51; Grant et al. 1994, pp. 134–135; Hutson et al. 2001, p. 139; Palmeirim et al. 2005, p. 28). Pacific sheath-tailed bats are commonly found sharing caves with swiftlets (Aerodramus spp.) (Lemke 1986, p. 744; Hutson et al. 2001, p. 139; Tarburton 2002, p. 106; Wiles and Worthington 2002, p. 7, Palmeirim et al. 2005, p. 28). Little is known about the life history of the South Pacific sheath-tailed bat. The bat’s generation length (the average age of parents of the current cohort, reflecting the turnover rate of breeding individuals in a population) is believed to be 2.5 years (Pacifici et al. 2013). Reports confirm a highly aggregated roosting pattern for individuals of this species in Fiji and American Sāmoa (Scanlon et al. 2014, p. 456; Palmeirim et al. 2005, pp. 55–62), with large aggregations (100s to 1,000s) in a single “main” cave and a few individuals (1s to 10s) often scattered in several caves close to this location.