Common Name: Sac-winged Bats, Sheath-tailed Bats
Taxonomy: Infraorder Yinochiroptera, Superfamily Emballonuroidea, 2 Subfamilies, 12 genera, 48 species
Distribution: Wide geographic range includes neotropics (much of southern Mexico, Central America, and northern South America), most of Africa, southern Asia, most of Australia, and the Pacific Islands east to Samoa.
Fossil Record: mid Eocene to early Miocene in Europe, Early Miocene to recent in Africa, and Pleistocene to recent in South America and other parts of the range; first fossil record is Eocene (~50 million years ago)
Size Range: head - body length 37 - 157 mm; tail 6 - 36 mm, forearm 37 - 97 mm, weight (adults) 5 - 105 g
Characteristics:
Most are grey, brown or black; species of the genus Diclidurus (Ghosts Bats) are white, other species have white or yellow on their wings or body
Face and lips are generally smooth - no nose leaf
Ears are often united across the top of the head; tragus present in all species
Many species have glandular wing sacs that open on the upper surface of the propatagium and secrete substances that have a strong odour. These sacs are more developed in males and are thought to act in mate attraction or territory marking. In some species the glandular mass is located in the throat area (Genus Taphozous)
Wing shape is variable; in some species of Taphozous the wings are long and narrow allowing for swift flight. Tail emerges from the dorsal surface of the uropatagium (tail membrane); base of tail is loosely enclosed in the membrane. At rest often fold wing tips back on their upper surface.
In flight the tail membrane is lengthened by stretching the hind limbs and it slides over the tail vertebrae; the extended membrane allows for exceptional steering during flight
Molar teeth have a W pattern of cusps and ridges. Dental formula varies. Shoulder and elbow joints are primitive
Known to roost in rocky crevices, caves, ruins, houses, trees, curled leaves, and hollow logs. Some roost in colonies, others are solitary. In most species males and females remain together year-round
Most are insectivorous; some are frugivores.
(from the books "Bats - A Natural History" and from "Walker's Bats of the World")