Saccopteryx canescens Thomas 1901

52. Frosted Sac-winged Bat

Saccopteryx canescens

French: Saccoptère givré I German: Weissgraue Sackflügelfledermaus I Spanish: Sacóptero escarchado

Other common names: Frosted White-lined Bat, Gray White-lined Bat

Taxonomy. Saccopteryx canescens Thomas, 1901,

“ Obidos,” Para, Brazil.

Two subspecies are recognized.

Subspecies and Distribution.

S. c. canescens Thomas, 1901 - E Colombia, most of Venezuela, the Guianas, E Peru, and W & N Brazil.

S. c. pumila Thomas, 1914 - lower Orinoco in Venezuela, distribution outside this area is not understood.

Descriptive notes. Head—body 38-44 mm, tail 16-18 mm, ear 11-14 mm, hindfoot 6-5—8 mm, forearm 35-39 mm; weight 3-5 g. Dorsal fur of the Frosted Sac- winged Bat is tawny to gray-brown, frosted with gray or yellow hair tips especially on head. Venter is paler and also composed of bicolored hairs. There usually are two, wavy, white lines on back, but they can be indistinct. Fur extends onto wings for about one-third the length of distance to elbow and onto uropatagium completely to distal tip of tail. Glandular sac is well developed in males and lies on propatagia close to elbows. Flight membranes are brown. Eyes are large, with brown irises. Ear is narrow. Tragus margin is smooth and rounded.

Habitat. Lowland, multi-strata, evergreen forests, often near streams and wetlands, and clearings from sea level to elevations of c.500 m.

Food and Feeding. The Frosted Sac-winged Bat feeds on tiny aerial insects while foraging over streams and rivers, wetiands, clearings, tree gaps, towns, and pastures. It will forage in vegetative clutter.

Breeding. Lactation of the Frosted Sac-winged Bat occurs in July in Venezuela.

Activity patterns. The Frosted Sac-winged Bat roosts under boulders and in rock piles and buildings.

Movements, Home range and Social organization. Roosting groups of Frosted Sacwinged Bats are alert and fly in tight formations as a group to escape disturbance. Groups consist of 5—15 individuals. One group of five individuals included one adult male, two adult females, a subadult female, and a subadult male, suggesting a harem structured breeding system.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Frosted Sac-winged Bat has a large distribution and presumably large and stable overall population.

Bibliography. Davis (1976 a), Eisenberg (1989), Emmons & Feer (1997).