Eptesicus furinalis - Argentine Brown Bat

Figure 1. Eptesicus furinalis

Photo courtesy of Nancy Simmons.

Simmons@nmnh.org

Physical Description:

Eptesicus furinalis is different from most vespertilionids by having a large broad head, husky body, short rounded ears and short broad wings. The ears and membranes are naked and dark in color. The face is plain without a noseleaf and the tail is shorter than the head and body and completely ensheathed within the uropetagium with the wing membranes starting at the toes (Emmons, 1990; Kurta, 1996).

Depending on where this specie is found the coloration will vary. The dorsal fur generally is blackish but can be dark brown with the venter being paler with sometimes a yellowish and orange tint (Redford, 1992).

The skull has a flat rostrum with a little sagittal crest. The dental formula is i 2/3, c 1/1, pm ½, m 3/3, total 32. The first upper incisor has a secondary cusp compared to the second incisor which is half the length and has no cusp (Kurta, 1996).

The average body mass is 7.5-9g with the females being slightly larger than males by 1.5g. The total length is 93-97mm, tail=37-39mm, hindfoot=9-10mm, ear=16mm, body=52mm, and forearm length=38mm (Redford, 1992). There are seven subspecies of this species.

Distribution:

Eptesicus furinalis is widely distributed throughout Central and South America. There have been records of findings in Belize, Costa Rica, Guatemala, Honduras, Nicaragua and Panama for Central America. South America has records for findings in Argentina, Bolivia, Brazil, Colombia, Ecuador, French Guiana, Paraguay, Peru and Venezuela. The northern most rage for Eptesicus furinalis is near Tamaulipas Mexico and the southern most range is the Argentine province of La Pampa, about the 37˚ parallel (Eisenberg, 1989; Kurta, 1996).

Ontogeny and Reproduction:

There are two breeding periods during the year for this species. The first period occurs in late July and early August with a gestation period lasting about three months. Copulation follows parturation thereby proving that females store sperm. The number of embryos for the first pregnancy is 1.9 whereas the number for the second pregnancy is one. The age at which this species becomes sexually mature and begins to reproduce is less than one year (Redford, 1992).

Ecology and Behavior:

Little is known about the habitat of this bat other than the data collected by accidental captures in mist nets. This species is known to inhabit many biomes as Willeg et al’s “Paraguayan Bat Assemblages” shows. The biomes are as follows: Alto Chaco, Bajo Chaco, Campos Cerrados, Central Paraguay, Alto Paran¢a, and Neembucu. These areas have scrub forests, palm savannas, semi-arid regions, dense forests, grasslands, sub-humid forests, and wetlands. They are generally known to be in higher altitudes of 1580m and prefer moist habitats and montane tropical forests (Eisenberg, 1989).

This specie roosts under the bark of trees, within walls and floors, attics, and hollows in trees. They are also known live in caves and go through daily torpor (Eisenberg, 1999; Kurta, 1996)

The main diet of this bat consists of aerial insects and seems to be the first bat out feeding due to the capture records in mist nets, being the first one captured.

There are two known parasites for this bat: Vampirolepis pandoensis a hymenolopid cestode and the nycteribiid batfly Basilia wenzeli (Kurta, 1996)

Literature Cited:

Eiseberg, John F. 1989. Mammals of Neotropics: The Northern Neotropics. The University of Chicago Press, Chicago and London. Vol 1, 449pp

Eiseberg, John F. and Redford, Kent H. 1999. Mammals of Neotropics: The Central Neotropics. The University of Chicago Press, Chicago and London. Vol 3, 609pp

Emmons, Louise H. 1990. Neotropical Rainforest Mammals: A Field Guide. The University of Chicago Press, Chicago and London. 281pp

Kurta, Allen, R, Mies, and D. G. King. 1996. Eptesicus furinalis. Mammalian Species. No. 526, pp 1-7

Redford, Kent H and Eiseberg, John F. 1992. Mammals of Neotropics: The Southern Cone. The University of Chicago Press, Chicago and London. Vol 2, 430pp

Reference written by Nathan Weitz, Biology 378 (Mammalogy), University of Wisconsin – Stevens Point. Edited by Christopher Yahnke. Page last updated 08-05-05.