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Nyctophilus geoffroyilesser long-eared bat

By Ross Secord

Geographic Range

All of Australia (except the northeastern peninsula) and Tasmania (Strahan, 1983).

Habitat

Nyctophilus geoffroyi exploits a wide range of habitat, including man-made structures such as attics and awnings. It roosts in dead trees, under tree bark, under rocks, in bird nests, and in caves. One study found that it prefers dead trees for roosts, particularly dead Banksia trees (Hosken, 1996). It tolerates a wide range of climate, including semi-arid, temperate, and tropical. It can tolerate extreme heat with temperatures up to 104 degrees Fahrenheit. Like other vespertilionids, Nyctophilus geoffroyi is also capable of handling cold conditions by entering torpor for much of the day in winter months. While in torpor body temperature is lowered and metabolic rate drops, conserving energy (Strahan, 1983; Hosken, 1999).

Physical Description

The head and body of Nyctophilus geoffroyi are covered in light gray to brown thick fluffy fur, with darker shades dorsally, and lighter shades ventrally. The ears are large, elongate, and joined across the forehead by a band of integument. The tragus is short. The tail extends to the end of the uropatagium. Fur is absent on wings and connecting membranes. Nyctophilus geoffroyi possesses a well developed noseleaf (unusual for vespertilionids) with a Y-shaped central groove. Its molars are dilambdadont and its canines small (Strahan, 1983).

  • Range mass
    6 to 8 g
    0.21 to 0.28 oz

Reproduction

Nyctophilus geoffroyi forms maternity colonies in spring, and young are born in the late spring or early summer. Maternity colonies are made up of as few as 10 to more than 100 individuals. Gender composition varies regionally, and some colonies are composed wholly of pregnant females, while others contain males and females. Females give birth to one or two offspring (twinning is common), which are typically left in the roost for about six weeks, after which time they begin to fly and hunt with their mother. Parental-offspring relationships apparently do not last after weaning (Strahan, 1983; Hosken, 1997).

  • Range number of offspring
    1 to 2

Behavior

Nyctophilus geoffroyi is nocturnal. During warm months it becomes active shortly after dark and remains active until dawn. During cold months, however, it may only be active for an hour or so per day. It uses a short-range echolocation system and hunts for insects in the air and possibly on the ground. It has a slow, fluttering flight with a high degree of maneuverability. Unlike many other bats that can only fly from a hanging position, it is capable of flight from horizontal surfaces. Nyctophilus geoffroyi is a tenacious bat very reluctant to give up nesting sites, even in the face of extreme disturbances, a behavior that accounts in part for its ability to live in close proximity to humans. Females are gregarious during pregnancy and while raising young, but females and males may be solitary for much of the year (Strahan, 1983; Nowak, 1997).

Communication and Perception

Food Habits

The diet of Nyctophilus geoffroyi consists primarily of a variety of airborne insects captured in flight using both echolocation and sight (Grant, 1991). Several authors have also noted that N. geoffroyi captures insects such as beetles from branches and bark, and even from the ground, and is a low flying predator (Nowak, 1997; Strahan, 1983, Grant, 1991). This view has been questioned, however, by Brigham et al. (1997), who observed that N. geoffroyi rarely descends to the ground, but rather spends most of the time 2-5 meters above the ground. Bailey and Haythornthwaite (1998) demonstrated that N. geoffroyi can also use its hearing to locate insects that generate sound, such as crickets, independently of echolocation.

Economic Importance for Humans: Positive

Nyctophilus geoffroyi consumes a great biomass of insects, many of which are destructive to agriculture or are considered pests (Strahan, 1983).

Economic Importance for Humans: Negative

Because Nyctophilus geoffroyi often chooses human structures to nest or roost in, and has even been found in laundry left out to dry (Strahan, 1983), it is considered a pest by some. Its close proximity to humans also presents the possibility of transmitting diseases, although I found no reference any disease transmitted by this bat.

Conservation Status

Nyctophilus geoffroyi is found in great abundance locally. Because it exploits habitat made by humans, such as garages, barns, and attics, its numbers may have even increased in developed areas. Since many of the insects it feeds on, however, also feed on crops, the use of insecticides could be detrimental to bat populations (Strahan, 1983). Additionally, outside of the populated areas where N. geoffroyi is typically observed, it was found roosting only in dead trees in old-growth forest. No roost sites were observed in re-growth forest, suggesting that the preservation of old-growth forest may be necessary to preserve populations of N. geoffroyi in undeveloped areas (Taylor and Oneill, 1988; Hosken, 1996).

Other Comments

Nyctophilus geoffroyi will take insect offerings from and sometimes even land on a person's hand (Nowak, 1997), exhibiting an apparent lack of fear or indifference toward humans.

Contributors

Ross Secord (author), University of Michigan-Ann Arbor, Phil Myers (editor), Museum of Zoology, University of Michigan-Ann Arbor.

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chaparral

Found in coastal areas between 30 and 40 degrees latitude, in areas with a Mediterranean climate. Vegetation is dominated by stands of dense, spiny shrubs with tough (hard or waxy) evergreen leaves. May be maintained by periodic fire. In South America it includes the scrub ecotone between forest and paramo.

chemical

uses smells or other chemicals to communicate

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

Bailey, W., S. Haythornthwaite. 1998. Risks of calling by the field cricket Teleograyllus oceanicus; potential predation by Australian long-eared bats. Journal of Zoology (London), 244(4): 505-513.

Brigham, R., R. Francis, S. Hamdorf. 1997. Microhabitat use by two species of Nyctophilus bats: A test of ecomorphology theory. Australian Journal of Zoology, 45(6): 553-560.

Grant, J. 1991. Prey location by two Australian long-eared bats Nyctophilus-gouldi and Nyctophilus-geoffroyi. Australian Journal of Zoology, 39(1): 45-56.

Hosken, D. 1997. Reproduction and the female productive cycle of Nyctophilus geoffroyi and and N. major (Chiroptera: Vespertilionidae) from South-western Australia. Australian Journal of Zoology, 45(5): 489-504.

Hosken, D. 1996. Roost selection by the lesser long-eared bat, Nyctophilus geoffroyi, and the greater long-eared bat, N. major (Chiroptera: Vespertilionidae) in Banksia woodlands. Journal of the Royal Society of Western Australia, 79(3): 211-216.

Hosken, D., P. Withers. 1999. Metabolic physiology of euthermic and torpid lesser long-eared bats, Nyctophilus geoffroyi (Chiroptera: Vespertilionidae). Journal of Mammalogy, 80(1): 42-52.

Nowak, R. 1997. "Walker's Mammals of the World 5.1 Online" (On-line). Accessed December, 1999 at http://www.press.jhu.edu/books/walkers_mammals_of_the_world/marsupialia/marsupialia.dasyuridae.antechinus.html.

Strahan, R. 1983. Complete book of Australian mammals: the national photographic index of Australian wildlife. London, Sydney, and Melbourne: Angus and Rorertson.

Taylor, R., M. Oneill. 1988. Summer activity patterns of insectivorous bats and their prey in Tasmania Australia. Australian Wildlife Research, 15(5): 533-540.

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