Plecotus auritus
brown big-eared bat

Plecotus auritus is found all across Eurasia, from Spain east to Japan, and south into India. (Roberts and Hutson, 2004; Swift, 1998)

In general, P. auritus seem to prefer higher altitudes. In the summer, the long-eared bat can most often be found roosting in hollow trees at the edge of parks or woodlands. They are also commonly found clustering next to a chimney or along the beams of large roof spaces in stables, barns, lofts, and older buildings. From mid October to early April they hibernate in caves, mineshafts, hollow trees, under roofs, and in underground sites. Favorite roost sites of the long-eared bat can often be indicated by stains on the timbers. (Burton, 1962; Roberts and Hutson, 2004; Swift, 1998)

As their common name implies, P. auritus have large ears--almost as long as their bodies. When in flight, the bats hold the ears fully erect and extended forward. At rest, their ears fold and curl sideways in a way that resembles ram horns. During hibernation the bats fold and tuck ears down, so that only the long pointed ear cover is visible.

P. auritus have relatively large eyes without a tapetum lucidum, and slit-shaped nostrils that open laterally. They usually weigh 6-12 grams and females are slightly larger than males. They have long, silky fur that is brownish on the upper side and grayish brown below. The dental formula for the P.auritus is 2/3, 1/1, 2/3, 3/3=36.

(Grzimek, 1975; Howard, 1995; Swift, 1998)

Climate is a very important factor for the survival of the young long-eared bat. Poor weather during lactation results in delayed growth, abandonment by mother and high mortality. Although records show that P. auritus are able to live up to thirty years, the average lifespan is seven years for males, sixteen years for females, and fifteen years for the sexes combined. High longevity could be due to the large amounts of time spent in a state of torpor, when the metabolic rate is very low. (Howard, 1995; Swift, 1998)

P. auritus group together in relatively small groups (no more than 80 individuals). The only social relationship that has been identified is the mother/offspring relationship. Females remain in natal roosts their entire lives and males are likely to depart to another roost.

Long-eared bats emerge from roost after sunset and do not return again until shortly before sunrise. They hover in the confined roost briefly before emerging, displaying their ability to remain stationary in the air without any forward motion. There is no convincing evidence of migration of P. auritus, but they do hibernate from autumn to March.

(Grzimek, 1975; Swift, 1998)

P. auritus are insectivorous, feeding mainly on Lepidoptera (moths). They are opportunistic foragers, feeding on the most available insects, including beetles, flies, earwigs, and spiders. Long-eared bats forage in a variety of ways, such as catching insects in free flight, landing on the ground to capture prey, or hovering in mid-air to listen for movements of insects to pick them off the foliage. They forage at night, usually relatively close to their roost.

(Burton, 1962; Roberts and Hutson, 2001)

Long-eared bats avoid most predators by only flying at night; however, they are still sometimes captured by some nocturnal predators such as owls and cats. The domestic cat is the most significant mammalian predator, especially to bats roosting under the roofs of houses. Their habit of flying close to the ground to forage and landing to catch insects makes them especially vulnerable to cats. (Roberts and Hutson, 2004; Swift, 1998)

P. auritus harbor relatively few parasites comparted to other bats, perhaps due to its small colony size. Several species of fleas in the family Ischnopsyllidae and mites in Spinturnicidae have been recorded on long-eared bats.

The only species of internal parasites that have been noted in P. auritus are bacteria in the genus Grahamella. (Swift, 1998)

They consume large numbers of insect pests.

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