Great Evening Bat

The great evening bat is the largest bat in the vesper bat family and the only living species in its genus. It is brown on top and greyish underneath, reaches 90–105 mm in length, has an average wingspan of about 51 cm and typically weighs about 58 g. It is common in eastern and south-eastern Asia (China, India, Laos, Nepal, Thailand and Vietnam), mainly in areas with limestone caves at about 400–1,700 m (Wikipedia, general species account).

It usually lives in small groups, and roost sites have been found both near cave entrances and up to 1.5 km inside cave systems. It sometimes feeds on small birds in autumn when insects become scarce, and in winter it may migrate to warmer regions. Its constantly shifting diet makes it a suitable host for viruses.