Great evening bat

The great evening bat (Ia io) is the largest bat in the vesper bat family (Vespertilionidae) and the only living species in the genus Ia. It is common to Eastern and Southeastern Asia (China, India, Laos, Nepal, Thailand and Vietnam), mainly living in areas with limestone caves at altitudes of 400 - 1700 m. Their roost sites have been found both near the cave entrances and up to 1.5 km within the cave systems.

Description
The great evening bat reaches a length of 90 to(-). It is colored brown on the top and grayish on the bottom. Average wingspan is 51 cm and it typically weighs 58 g.

Not much is known about its habits and behavior. The bat usually lives in small groups. Its food consists of insects, as with most vesper bats. The great evening bat also sometimes feeds on small birds. The bat leaves its sleeping place in the late afternoon to search of food. During the winter months it may migrate to warmer regions.

Status
The IUCN lists its conservation status as near-threatened. One of the threats to its survival in South Asia is human influence by habitat destruction; many caves have been turned into attractions. They have also been disturbed by farmers collecting their excrement. Also the excessive use of insecticides poses a threat to the great evening bats.

Scientific name
At four letters, Ia io is tied with Yi qi for the shortest existing (and shortest possible) scientific name of any animal under the International Code of Zoological Nomenclature, and is one of very few scientific names composed solely of vowels.

The name has traditionally been associated with Io, a figure in classical mythology who was viewed as "flighty," and ia (ἰά), a Greek word signifying a shout or cry.

However, recent interpretations by Griffiths (2022) suggest an alternative meaning behind Oldfield Thomas's choice of name. Instead of a reference to mythology, the name Ia io might be a joyful exclamation, translating to 'Shout hurrah!'. This interpretation posits that Thomas, who had recently become a Fellow of the Royal Society, was expressing his elation through the naming of this species. This explanation adds a new layer to the understanding of the species name, considering Thomas's scholarly background and the timing of the bat's discovery.