Tonatia silivicola - White-throated Round-eared Bat
Physical Description:
Tonatia silvicola is a medium-sized leaf-nosed bat and is generally accepted as the largest species of the genus in many areas (Medellin 1989) with weights of 21-38 grams (Bernard & Fenton 2003); males are typically larger than females. T. silvicola has long, round ears with wide wings and a short tail. The tail is stationed completely within the uropatagium. The lower lip pads form a V and are covered with poorly developed granular warts. The hair color varies with the geography from pale gray or brown to dark black. Many T. silvicola have a white patch that typically extends from the throat to the chest, hence its common name (Medellin 1989).
Tonatia silvicola has a well-built skull with large cheek teeth and long canines without spaces between them. The braincase is exaggerated and elongated with a distinct sagittal crest forming in the lower forehead (Medellin 1989) and is characterized by prominent postorbital constriction (Porter et al. 2003).
Distribution:
Tonatia silvicola occupies areas from Nicaragua in Central America to Southern Brazil, Bolivia, and Paraguay in South America. It lives at altitudes from sea level up to 1,500 km (Medellin 1989).
Geographic distribution of Tonatia silvicola (Figure from Medellin 1989).
Ontogeny and
Reproduction:
Tonatia silvicola has a litter size of one and is typically diesterous. Various data have been collected and state that there are two birth peaks around January and around July and evidence suggests some females undergo postpartum estrus. This could be due to the seasonality of the forest and the continuity of resources being available (Medellin 1989).
Ecology and Behavior:
The diet of T. silvicola consists of insects and fruits (Medellin 1989). It is attracted to prey based on the prey’s sound emissions. In a study by Tuttle et al., T. silvicola was attracted to singing male katydids but not silent female katydids (1985).
Tonatia silvicola inhabits areas of various vegetation from rainforests to drier areas (Medellin 1989) and roosts in both hollow tree cavities and active termite mounds (Bernard & Fenton 2003). It lives in groups of 6 to 18 individuals (Medellin 1989) and is one of few species to use the same roost through consecutive nights. Its day roosts are in close proximity to the areas used at night (Bernard & Fenton 2003), commuting only 200-500 meters from the day roosts to the night foraging sights, the latter being only 3-4 hectares. T. silvicola can be sustained by such small foraging areas because of the highly productivity of the tropical forests it inhabits (Bonaccorso et al. 2001).
Remarks:
Tonatia silvicola has a generally positive impact for humans in regards to insect control. Also, the Nambiquara Indians in Western Brazil have been known to include T. silvicola along with other bats in their diets (Sets & Sazima 1987).
Literature Cited:
Aguirre, L. 2000. Structure of a neotropical savanna bat community. Journal of Mammology. 83(3): 775.
Bernard, E., M. B. Fenton. 2003. Bat mobility and roosts in a fragmented landscape in Central Amazonia, Brazil. Biotropica. 35(2): 262.
Bonaccorso, F., J. Winkelmann, E. Dumont, K. Thibault. 2001. Home Range of Dobsonia minor (Pteropodidae): A Solitary, Foliage-roosting Fruit Bat in Papua New Guinea. Biotropica, 34(1): 127.
Medellin, R., H. Arita. 1989. Tonatia evotis and Tonaia silvicola. Mammalian Species. No. 334: 1-5.
Porter, C., S. Hoofer, R. VanDenBussche, T. Lee, Jr., R. Baker. 2003. Systematics of round-eared bats (Tonatia and Lophostoma) based on nuclear and mitochondrial DNA sequences. Journal of Mammology, 84(3): 791-808.
Sets, E., I. Sazima. 1987. Bats Eaten by Nambiquara Indians in Western Brazil. Biotropica, 19(2): 190.
Reference written by Michael Dobbertin, Biol 378 (Mammalogy), University of Wisconsin – Stevens Point. Edited by Christopher Yahnke. Page last updated August 15, 2005.
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