endages of microbats that focus nasal emitted ultrasound. The ultrasound signal is usually produced orally, and many species have large exte

rnal ears to capture and reflect sound, enabling them to discriminate and extract info

rmation. The vespertilionids employ a range of flight tech

niques. The wing surface is extended to the lower limbs, and the tails of this family are enclosed in an interfemoral membrane. Some are relatively slow-flying genera, such as Pipistrellus, that manipulate the configuration of their broader wing shape and may give a fluttery appearance as they forage and glean. Others are specialised as long-winged genera, such as Lasiurus and Nyctalus, that use rapid pursuit to capture insects. The size range of the family is 3 to 13 cm (1.2 to 5.1 in) in head and body length; this excludes the tail, which is itself quite long in many species. They are generally brown or grey in colour, often an indiscriminate appearance as a 'little brown bat', although some species have fur that is brightly colored, with reds, oranges, and yellows all being known. The patterns of the superficial appearance include white patches or stripes that may distinguish some species. Most species roost in caves, although some make use of hollow trees, rocky crevices, animal burrows, or other forms of shelter. Colony sizes also vary greatly, with some roosting alone, and others in groups up to a million individuals. Species native to temperate latitudes typica