Tonatia silvicola
White-throated Round-eared Bat
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).
Figure 2. Dorsal, ventral, and
of cranium and lateral view of
of Tonatia silvicola (Medellin
lateral view
mandible
1989).
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).
.
Figure 1. Geographic distribution of Tonatia silvicola (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).
Behavior and ecology
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).
References
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.
http://www.angelo.edu/faculty/lammerma/batphotos.html
Tonatia silvicola
Reference written by Michael Dobbertin, Biol 378 (Mammalogy), University of Wisconsin – Stevens
Point. Edited by Christopher Yahnke. Page last updated August 15, 2005.