Diclidurus albus
northern ghost bat

Diclidurus albus is rare but widespread, ranging from Mexico to eastern Brazil. It is also found on some Caribbean Islands including Trinidad. During the summer months no sightings of D. albus have been made in Mexico, the northern edge of its range. This suggests that members of this species migrate south seasonally, from May to October. Little information is available on D. albus migration patterns. (Ceballos and Medellin, 1988; Eisenberg and Redford, 1999; Jones and Hood, 1993)

Northern ghost bats prefer humid habitats like riparian and tropical rainforests but have been found in human-disturbed areas like plantations, clearings, and over villages. They prefer to roost underneath the fronds of palms, including coconut, chocho palms, and coquito palms. These bats have also been seen in less mesic habitats, like deciduous and evergreen forests. Diclidurus albus migrates within the Neotropics. They occur from sea level to 1500 m. They were observed at highest elevations in Costa Rica. (Ceballos and Medellin, 1988; Eisenberg and Redford, 1999; Jones and Hood, 1993; LaVal, 2004)

Diclidurus albus is a distinctive looking bat species. The common name, northern ghost bats, refers to their soft, long, white pelage. Sometimes the proximal ends of the hairs are grey in color, while the distal ends are white, giving the animal an ashy grey tone. The patagia are pinkish and translucent and the tail is short, about one third the length of the uropatagium. The tail punctures the uropatagium, with the end projecting dorsally. The uropatagium is large with about two-thirds covered in fur, and extends beyond the hind feet. Northern ghost bats have nearly naked faces with large eyes and shorter, yellowish ears. They do not have a nose leaf, and their tragus is prominent, broad, and rounded. (Ceballos and Medellin, 1988; Eisenberg and Redford, 1999; Engstom and Lim, 1999; Jones and Hood, 1993; Vaughan, Ryan, and Czaplewski, 2000)

Diclidurus albus lacks the wing sacs that other Emballonuridae have. Instead, these bats have a unique gland on their uropatagium. This gland has two valves and is triangular in shape. Its actual function isn’t known, but it is larger in males, and becomes even more prominent during the breeding season. Northern ghost bats have vestigial thumbs, unlike other species in the genus. (Ceballos and Medellin, 1988; Engstom and Lim, 1999; Jones and Hood, 1993)

The skull is distinctive. The rostrum angles upward steeply from the braincase. The zygomatic arches are complete and the skull has strong supraorbital ridges. Premaxillae do not meet and have nasal branches only. The canines project forward and outward. The dental formula is I: 1/3, C: 1/1, PM: 2/2, M: 3/3 = 32. Cheek teeth are dilambdodont and have cingula. (Ceballos and Medellin, 1988; Jones and Hood, 1993; Vaughan, Ryan, and Czaplewski, 2000)

Northern ghost bats are at the larger end of the size range for Emballonuridae, with total lengths ranging from 86.0 mm to 103.0 mm. Tail lengths vary between 18.0 mm and 22.0 mm. Diclidurus albus differs from its congeners in that the length of its forearm is between 60 mm and 70 mm, while other species of this genus have forearms less than 60 mm or above 70 mm, or are distinguished by brownish pelage. Adult D. albus weigh between 17 and 24 g. They are sexually dimorphic; females tend to be larger in size and length, but this varies regionally. For example, in Mexico, both sexes were very similar in all measurements. The average female length was 88.0 mm, with the average male length being 89.0 mm. In Guatemala, however, females were about 10 mm longer than the males, with an average length of 102.0 mm compared to 92.5 mm for males. Sample sizes are relatively small, however, and more research is needed to verify the presence of sexual dimorphism in D. albus. (Ceballos and Medellin, 1988; Engstom and Lim, 1999; Hernandez et al., 1985; Jones and Hood, 1993; Vaughan, Ryan, and Czaplewski, 2000)

Northern ghost bat lifespans have not been studied.

Northern ghost bats are solitary. They do not form colonies and are found in small groups only during the breeding season. Northern ghost bats are nocturnal and roost under palms during the day. They tend to fly high and in reasonably straight lines. Most studies of D. albus have focused on physical properties instead of behavioral characteristics, so the behavior of this species is not well known. (Ceballos and Medellin, 1988; Eisenberg and Redford, 1999; Engstom and Lim, 1999; Jones and Hood, 1993)

Home Range

The home range size for D. albus is unknown.

Northern ghost bats use echolocation to find prey and to navigate their way through the nighttime forest. They emit a call at 22 kHz while hunting. No information is available about communication between individual bats, although chemical communication is likely, including the use of gland secretions by males. (Zorpette, 1999)

Like all members of the family Emballonuridae, northern ghost bats are insectivorous. Stomach contents have a high proportion of moths. (Ceballos and Medellin, 1988; Eisenberg and Redford, 1999; Engstom and Lim, 1999; Jones and Hood, 1993)

Northern ghost bats are nocturnal and solitary, which helps to protect them from many predators. Predation on northern ghost bats has not been recorded.

Northern ghost bat individuals eat around 1,000 insects a night. This could affect insect populations. These bats are rare, so their effect on the ecosystem are probably slight and can only be a hypothesized based on the effects of other bats in the area. Also, bat guano is very important to plants, providing excellent fertilizer. (Zorpette, 1999)

Like most wild mammals, northern ghost bats can transmit rabies to humans and other animals. However, rabies transmission to humans is rare. (Jones and Hood, 1993)

Northern ghost bats may be important in helping keep agricultural pest populations in check, but their rarity suggests that they might not contribute much to insect control. Also, because this bat is attractively colored and rare, may help draw ecotourists to an area. With knowledgeable guides, nighttime bat tours can attract tourists. (Lim and Engstrom, 2005; Zorpette, 1999)

IUCN lists D. albus as being at lower risk and least concern. Although northern ghost bats are rare throughout their range, they are widespread. (Chiroptera Specialist Group 1996, 2004)

Two subspecies are sometimes recognized, D. a. albus and D. a. virgo. Previously, Diclidurus scutatus was considered a synonym of D. albus, but is now considered a separate species, about which very little is known. Controversy abounds over who deserves the credit for naming D. albus. Oken may have been responsible, but credit is usually given to Wied (1820). No fossils are known for the entire genus Diclidurus. Other common names include murciélagos blancos (Spanish), and gespenstfliedermaus (German). The generic name, Diclidurus arises from the gland on the tail. The Latin word diclid means two-valved, and urus means tail. Albus in Latin means white, and relates to the white fur of these bats. (Ceballos and Medellin, 1988; Jones and Hood, 1993)