The serotine bat (Eptesicus serotinus), also known as the common serotine bat, big brown bat, or silky bat, is a fairly large Eurasian bat with quite large ears. It has a wingspan of around and often hunts in woodland. It sometimes roosts in buildings, hanging upside down, in small groups or individually. The name serotine is derived from the Latin serotinus, which means 'evening', while the generic name derives from Greek ἔπιεν and οίκος, which means 'house flyer'. Taxonomy The following subspecies have been recognised. Eptesicus serotinus boscai: southern Iberia and Morocco Eptesicus serotinus pashtonus: Pakistan and Afghanistan Eptesicus serotinus serotinus: northern and eastern Europe and western Asia Eptesicus serotinus turcomanus: central Asia and Xinjiang The Oriental serotine (E. pachyomus) and its constituent subspecies were formerly considered a subspecies of E. serotinus, comprising its eastern populations, and is still considered its closest relative, but phylogenetic evidence indicates a deep genetic divergence between E. serotinus and E. pachyomus, so they have been split as distinct species. The same occurred with the meridional serotine (E. isabellinus), which was formerly thought to comprise the southernmost populations of E. serotinus. Description The serotine bat has long fur which on the back is smoky-brown in colour, while the underparts are a paler yellowish-brown, the nose and triangular shaped ears are black, and the membranes of the wings are dark black or brown. The juveniles are darker than the adults. Serotine bats are easy to identify in flight, because its broad wings combined with its slow, highly manoeuvrable, flapping flight interspersed with brief glides is distinctive. The tragus has a relatively thin and pointed shape and is not kidney shaped as in Nyctalus. Distribution The serotine bat has a Palaearctic distribution lying between about 58 degrees and 30 degrees from southern Great Britain and Spain in the west, east to along the Himalayas to northeastern India and along the Tian Shan to southern Mongolia and northern China, and south to Turkey and Iran. It has been recorded as a vagrant on Lanzarote in the Canary Islands. Habitat The serotine bat utilises in a wide variety of habitats including temperate and subtropical dry forest, maquis, agricultural land, semi-desert and suburban areas. Biology In Europe serotine bats start to establish maternity colonies consisting almost exclusively of females from late May. Colonies usually remain at a single roost site during the breeding season, although occasionally the larger colonies will