The Chilean myotis (''Myotis chiloensis'') is a species of

vesper bat Vespertilionidae is a family of microbats, of the order Chiroptera, flying, insect-eating mammals variously described as the common, vesper, or simple nosed bats. The vespertilionid family is the most diverse and widely distributed of bat familie ...

found in southern South America.

Description

The Chilean myotis is a small bat, measuring only in total length, including the tail, and weighing about . The colour of their fur varies with latitude, from pale ochraceous in the north to coffee-brown in the south. They have a

wing aspect ratio In aeronautics, the aspect ratio of a wing is the ratio of its span to its mean chord. It is equal to the square of the wingspan divided by the wing area. Thus, a long, narrow wing has a high aspect ratio, whereas a short, wide wing has a low as ...

of 5.8, suggesting that they are slow, but highly manoeuvrable, in flight. The tail is entirely enclosed within the

uropatagium The patagium (plural: patagia) is a membranous body part that assists an animal in obtaining lift when gliding or flight. The structure is found in extant and extinct groups of flying and gliding animals including bats, birds, some dromaeosaurs, ...

Distribution and habitat

Apart from the southern big-eared brown bat, which lives in the same general locality, the Chilean myotis lives further south than any other bat species in the world. The species lives primarily in Chile, south of about 30°S, but is also found in the westernmost regions of the

Argentinian Argentines (mistakenly translated Argentineans in the past; in Spanish (masculine) or ( feminine)) are people identified with the country of Argentina. This connection may be residential, legal, historical or cultural. For most Argentines, ...

provinces of

Neuquén Neuquén (; arn, Nehuenken) is the capital city of the Argentine province of Neuquén and of the Confluencia Department, located in the east of the province. It occupies a strip of land west of the confluence of the Limay and Neuquén rivers w ...

, Río Negro, and Chubut. At the extreme southern end of its range, it is found across

Tierra del Fuego Tierra del Fuego (, ; Spanish for "Land of the Fire", rarely also Fireland in English) is an archipelago off the southernmost tip of the South American mainland, across the Strait of Magellan. The archipelago consists of the main island, Isla G ...

, in both the Chilean and Argentinian parts of the island. Over this wide area, it ranges from the semi-arid

Chilean Matorral The Chilean Matorral (NT1201) is a terrestrial ecoregion of central Chile, located on the west coast of South America. It is in the Mediterranean forests, woodlands, and scrub biome, part of the Neotropical realm. Matorral is typically character ...

in the north to temperate and evergreen forests in the south. There are no currently recognised subspecies, although the

montane Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures fall as elevation increases, causing the ecosystem to stratify. This stratification is a crucial f ...

and Atacama myotises, which live further north in western South America, and are now considered species in their own right, were formerly considered to be subspecies of ''M. chiloensis''.

Biology and behaviour

Chilean myotises roost in holes in trees, rock crevices, caves, and artificial structures such as attic spaces. They emerge at dusk, and feed for about three hours before returning home to roost; unlike most other bats they do not feed again later in the night. Because of their small size and low metabolic rate, the bats often enter a daily period of

torpor Torpor is a state of decreased physiological activity in an animal, usually marked by a reduced body temperature and metabolic rate. Torpor enables animals to survive periods of reduced food availability. The term "torpor" can refer to the time ...

during which their body temperature falls to just 0.5 °C above ambient. They feed on flies that they capture on the wing, particularly including

nematocera The Nematocera (the name means "thread-horns") are a suborder of elongated flies with thin, segmented antennae and mostly aquatic larvae. This group is paraphyletic and contains all flies but species from suborder Brachycera (the name means "sh ...

ns such as

crane flies Crane fly is a common name referring to any member of the insect family Tipulidae. Cylindrotominae, Limoniinae, and Pediciinae have been ranked as subfamilies of Tipulidae by most authors, though occasionally elevated to family rank. In the most ...

. Their echolocation calls consist of a downward

frequency modulated Frequency modulation (FM) is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave. The technology is used in telecommunications, radio broadcasting, signal processing, and computing. In analog freque ...

segment followed by a narrowband component at a relatively constant frequency. Search calls sweep down from 89 to 39

kHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that on ...

, and are emitted at intervals of about 95 milliseconds. Females give birth to a single young at the beginning of summer.

References

{{Taxonbar, from=Q1830919 Mouse-eared bats Bats of South America Mammals of Argentina Mammals of Chile Chilean Matorral Fauna of Tierra del Fuego Mammals described in 1840 Taxa named by George Robert Waterhouse Taxonomy articles created by Polbot