| Spectral Bat | |
|---|---|
| Conservation status | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Chiroptera |
| Family: | Phyllostomidae |
| Genus: | Vampyrum Rafinesque, 1815 |
| Species: | V. spectrum |
| Binomial name | |
| Vampyrum spectrum (Linnaeus, 1758) |
|
The Spectral Bat (V. spectrum) is a large, carnivorous leaf-nosed bat. Some alternate names for this species are the False Vampire Bat, Linnaeus's False Vampire Bat and the Spectral Vampire Bat. Confusingly, they are not related to the Old World family of large carnivorous bats to be found in the Megadermatidae that are also called false vampires.
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This species is the largest bat in the New World and the largest carnivorous bat in the world, having a wingspan of eighty centimeters or so (almost three feet) and a body length and weight of 125–135 millimeters and 145–190 grams respectively, though larger specimens with wingspans of over one hundred centimeters are not unknown. The ears are very long and rounded.[2] There is no discernible tail, but the tail membrane is long and broad. The large feet are robust, with long curved claws. The muzzle is long and narrow, and the teeth are strong with the upper canines being well developed. The skull is robust and has a well-developed sagittal crest which projects pass the foramen magnum.[2] The noseleaf is medium-sized, lance-shaped, horseshoe and spear with continuous rim raised to form a hollow cup around the nostrils. The fur on the dorsal region is long, soft and is reddish brown in color. The fur on the underside is shorter and paler.[2] The spectral bat is a fairly agile and powerful flier. It has been described as flying "at low speeds in crowded flight spaces, maneuvering deftly, perhaps often landing to make captures, and having the low speed lift capabilities to carry off large prey items".[3] When in flight, spectral bats produce pulses of 1.5-1.8 milliseconds. The terminal phase of echolocation seems to be very short, being 0.5 msec or less.[4] It is likely this species uses short pulses of low intensities because it flies close to obstacles and near the ground.[5] It appears that spectral bats can discriminate between two similar targets.[4]
The spectral bat ranges from Veracruz, Mexico, southward to the island of Trinidad, central Brazil and Peru. It appears that the bat is restricted to Neotropical forest regions elevations ranging from sea level to 1,650 m.[6] This species seems to prefer to live in lowlands and foothills, streamsides, evergreen forests, yards and swamps.[7] Because of its carnivorous diet and large size, the spectral bat has a ecological niche unique among bat species.[2] The spectral bat is list as Near Threatened by the IUCN "due to its dependence on primary forest habitat and is rare and dispersed anywhere it is found, making it extremely susceptible to habitat fragmentation and population decline".[1] There are no major threats throughout its range but local threats include habitat fragmentation and destruction.[1]
The spectral bat is carnivorous, feeding on birds, rodent and even other bats.[8] With regards to avian prey, this species prefers to hunt birds that weigh between 20 and 150 grams (g), sleep in foliage rather than in holes or burrows, and either roost communally or have a strong body odor. In one bat roost, the remains of 84 birds from 18 species were found.[8] Non-passerines seem to be significantly preferred over passerines. When hunting, spectral bats use scent moreso than sight or echolocation to trace prey. One bat was recorded using nearby rivers as flyways to move between foraging areas on the edges of forests and tree clumps in pastures.[8] Upon locating prey, a bat will stalk it from above before striking.[9] The spectral bat is a slow and careful stalker and is more often successful in capturing bat than otherwise. When attacking, the bat drops down on the prey and graps it by the head near the snout or beak and its long canine teeth will sink into the skull. With the prey between its jaws, the bat then flys back to its roost. When feeding, the bat holds and steadies its prey with its thumb claws and masticates it.[9]
Hollow trees are the most common roosting sites for this species. Bats may roost solitarily or in small groups. It appears that births are limited to a single young at the end of the dry season or the beginning of the rainy season.[2][1] Overall, little is known about the reproductive cycle of this species. The spectral bat is perhaps the only bat species that forms long-term pair-bonds and lives in extended family groups.[10] Adults pairs will roost together in the same hollow tree for over a year and their offspring of three reproductions may remain with their parents. The spectral bat is one of only two species that shows evidence of male parental care (the other being the yellow-winged bat).[10] A least one adult male or older offspring will remain in the roost with the most recently born juvenile, while the other bats in the group go out to forage. Foragers may return to the roost with prey and the energy content of these prey may exceed the needs of a solitary forager.[10] Thus, it is likely that both the adults and the older offspring will guard the young and provision them with food.[8] The foraging habits of the spectral bat apparently involves an extended period of time during which the young learn to forage.[10] With the extended time in which parents are involved with their young and the provision of adult to offspring is what drove the selection for monogamy in this species.[8]