Nyctophilus geoffroyi
lesser long-eared bat

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

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).

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).

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).

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.

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.

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

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).

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.