Peropteryx macrotis Lesser doglike bat Description Peropteryx macrotis is the smallest member of the insectivorous genus Peropteryx (Yee 2000). P. macrotis is sexually dimorphic, the females are larger than the males in many body dimensions (Jones 1993). The rostrum and chin are elongated and naked, giving the bat a doglike facial appearance. The ears are unattached, and there is no white distally on the wings (Yee 2000). The dorsal pelage is dark brown to blackish brown, with a paler ventral surface (see figure 1) (Jones 1993). The fur is 6-9 mm long and is sparse. The wings have the emballonurid shape, and are attached to the tibia (Yee 2000; Jones 1993). Glandular wing sacs on the upper antebrachial membrane are outward opening. The tail is one-third the body length, and it perforates the interfemoral membrane (Yee 2000). The skull of P. macrotis is small, and has an expanded rostrum and forehead (Jones 1993). The postorbital process is long and slender and it has an undivided basisphenoid pit. The dental formula is I 1/3, C 1/1, P 2/2, M 3/3, with a total of 32 teeth. The incisors are small and simple (Yee 2000). Peropteryx macrotis may be easily confused with other members of the genus, including P. kappleri and P. leucoptera. These three species are similar in appearance. The distal portions of the wings are not white, and the ears are separate for P. macrotis and P. kappleri, while P. leucoptera does have white distal wing portions, and ears joined at the base by a membrane. P. macrotis can be separated from P. kappleri by the length of the body and skull. P. macrotis has a total length of less than 62 mm, and a skull length of no more than 15.5 mm. P. kappleri has a total body length of more than 62 mm, and a skull length of over 16 mm (Yee 2000). Distribution Peropteryx macrotis is a fairly widespread tropical bat. It is found from southern Mexico, throughout Central America, and into much of South America (figure 2). In South America, P. macrotis is found in Colombia, Ecuador, Peru, Venezuela, Guyana, Surinam, French Guiana, Brazil, and Paraguay. It is also found on some islands in the Caribbean, including Grenada, and Trinidad and Tobago (Yee 2000; InfoNatura 2004). There are three recognized subspecies. Peropteryx macrotis macrotis is found in Tobago, Central America, and South America. P. m. phaea is found on the Antillean Islands of Grenada, and P.m. trinitatis is found in Trinidad ( Jones 1993). Ontogeny and Reproduction Female P. macrotis bats are left cornu dominant, meaning ovulation and implantation occurs on the left side. P. macrotis breed during the dry season of January-June, and wet season of July-December, exhibiting seasonal polyestry. Gestation requires 4-4.5 months, and a single pup is common. The sex ratio of roosting P. macrotis bats is close to 1:1, but changes in July and August when juveniles mix into the groups of adults (Arita 1995). Colonies of P. macrotis may also form harems, which include one male and many females. The males perform courtship displays for the females, which utilize scents from the wing sac. The timing of breeding and lactation are variable throughout the range. Lactating females have been reported in January from Brazil, and from Mexico, in August, for example (Yee 2000). Ecology and Behavior Peropteryx macrotis is found in a variety of mesic habitats throughout its range, from Tropical Dry Forests to Tropical Rain forests (Genoud 1990). In Paraguay, P. macrotis is only fund in the Floodable Lands region. This region includes the lower or “wet” chaco. The lower Chaco is part of a vegetation transition area between Eastern subtropical forests, the western Chaco, and the pampas to the South (Lopez 2004). P. macrotis is not found above 1,000 meters, which is thought to be the elevational limit to its range (Yee 2000). The bat roosts in cool sites, such as small caves, tree hollows, rocky crevices, as well as human structures, but is most often found in short, simple caves (Jones 1993, Yee 2000). The roosts are often found in evergreen forests (Jones 1993). P. macrotis can be found less than 20 m from the entrance roosting on vertical or walls with steep inclines (Arita 1995). P. macrotis is usually observed roosting in groups of less than 12 individuals, but may roost alone, in groups of more than eighty, or in multiple groups (Arita 1995). P. macrotis roosts with bats of other species, including Peropteryx. kappleri, Saccopteryx bilineata, Glossophaga soricina, Glossophaga longirostris, Myotis nigrican (Yee 2000), Mimon cozumelae, Micronycteris megalotis, Carollia. perspicillata, Pteronotus. davyi, Mormoops megalophylla, Diphylla ecaudata, Myotis keaysi, Pteronotus parnellii, Desmodus rotundus, Natalus stramineus, Glossophaga soricina, and Artibeus jamaicensis (Arita 1996). The diet of P. macrotis includes small beetles and flies. P. macrotis catches its prey in flight. Near humans, the bats forage above roads and street lights (Yee 2000). Predators include owls (Yee 2000) and Chrotopterus auritus (Arita 1995). Parasites of P. macrotis include human bedbugs (Cimex hemipterus), Eimeria bragancaensis, an intestinal parasite, and nematode parasites (Lainson 2000). Remarks P. macrotis is known by several common names, including Peter’s Sac-Winged Bat, Lesser Dog-Like Bat, and the Neotropical Sac-Winged Bat (Yee 2000). Literature Cited Arita, H.T. 1996. The Conservation of Cave-Roosting Bats in Yucatan, Mexico. Biological Conservation. 76:77-185. Arita, H.T., and J.A. Vargas. 1995. Natural History, Interspecific Association, and Incidence of The Cave Bats of Yucatan, Mexico. The Southwestern Naturalist 40(1):29-37. Genoud M., F.J. Bonaccorso, A. Arends. 1990. Rate of Metabolism and Temperature Regulation in Two Small Tropical Insectivorous Bats (Peropteryx macrotis and Natalus tumidirostris). Comparative Biogeochemical Physiology. 97:229-234. InfoNatura: Birds, mammals, and amphibians of Latin America [web application]. 2004. Version 3.2. Arlington, Virginia (USA): NatureServe. Available: http://www.natureserve.org/infonatura. (Accessed: September 19, 2004). Jones, J.K., and C.S. Hood. 1993. Synopsis of South American Bats of the family Emballonuridae. Occasional Papers – The Museum Texas Tech University. 155:1-32. Lainson, R. and R.D. Naiff. 2000. On Eimeria bragancaensis n. sp. (Apicomplexa: Eimeriidae) and tissue-cysts of an unidentified protozoan in the bat Peropteryx macrotis (Chiroptera:Emballonuridae) from Amazonian Brazil. Parasite 7(2):123-129. Lopez, G.C. 2004. Ecological zoogeography of the bats of Paraguay. Journal of Biogeography 31(1) 33-45. Yee, D.A. 2000. Peropteryx macrotis. American Society of Mammalogists. 643. pp 1-4 Reference written by Melissa Hiles, Biology 378 (Mammalogy), University of Wisconsin – Stevens Point. Edited by Christopher Yahnke. Page last updated August 15, 2005.