You’re sitting on a rock in Sri Lanka, trying to capture the perfect photo of a small frog when all of a sudden there’s a a high pitched clicking sound, a flash of soft gray, the startled croak of the toad as it attempts to jump, and than … nothing. The toad and whatever that gray thing was are gone without a single trace. It’s as if they never existed.
A glance at your phone reveals a blurry image of the toad and just above it, the grey thing you saw. Zooming in reveals the fuzzy image of … a long eared, big winged bat.
Congratulations, you’ve just experienced a close encounter with a greater false vampire bat.
The greater false vampire bat (Megaderma lyra) has the word vampire in their name or that it’s a carnivorous species fool you. No matter how hungry the species gets, it doesn’t actively seek out blood. If there’s any human blood in its system, it came from eating an insect that recently finished feeding on a person.
About the Greater False Vampire Bat
If you hear the words carnivorous and false vampire bat and assume that the animal must be ugly, you’re in for a surprise. With their short, grayish colored back fur and white underside, large oval ears, and warm, expressive eyes, this is a very attractive species. Adults weigh anywhere from 40-60 g with a body length of 65-95 mm. The species doesn’t have an external tail and a rostrum connects the bat’s ears.
When kept in captivity, this species can live up to fourteen years.
Where to Find Greater False Vampire Bats
The species has a large range that includes:
- Sri Lanka
- Eastern Pakistan
- Southeastern China
- The northern part of the Malay Peninsula
When it comes to day roosts, they prefer settling into quiet buildings, caves, and hollow trees. The general rule of thumb is that day roosts contain a moderately sized colony of no more than 30 bats, but in India, there’s at least one seasonal colony that contains approximately 2000 greater false vampire bats. Researchers have also observed small contact cluster colonies that consist of about five different bats which are made up of a mother and her offspring. While roosting, this species likes to maintain about 9cm between one another. The males and females of the species happily share the same roosts.
Greater false vampire bats prefer to use the same day roost for years and years, indicating that the loss of the roost through habitat destruction would have a devastating psychological impact on the animals, though it’s unclear how they’d handle the stress and deal with relocating.
The Greater False Vampire Bats Bizarre Hunting Habits
What makes the greater false vampire bat stand out is that insects only make up a portion of its diet. The bat is strong enough and clever enough to also take on small song birds, the occasional fish, small lizards, and even, if the opportunity presents itself, other bat species.
If you love bat watching, you’ll have a great time observing the greater false vampire bat in action. While they’re hunting, these bats skim along the ground and the surface of quiet lakes and ponds. When they spot a tasty morsel, they snatch it directly off the ground. This hunting style is dubbed gleaning and bats such as the greater false vampire bat and the pallid bat are often referred to as gleaning bats.
This particular bat is up all-night long, and they’re not afraid to travel. There have been multiple reports of the adults flying approximately 4 kilometers from their roosting site in search of food.
The greater false vampire bat uses a combination of hunting practices. The bulk of its meals are obtained while the bat flies low, about a meter above the ground, and scans the landscape they’re flying over. When the bat spots a large bug, or a small lizard, they swoop down and grab it right off the ground!
About 15% of the time, the greater false vampire bat, changes its approach. Instead of actively hunting for prey, it finds a place to rest and stays very still, waiting for something edible to come along.
There are times when the bat relies on echolocation to help locate prey and at other times, they’ve been observed using a passive listening technique. So far, no one knows why or how the bat switches from one hunting method to another.
Once the bat makes a capture, they carry their food to a safe location where they settle in and start dining.
Breeding and Caring for Young
Males and females get together during the breeding season which generally runs from November to January. Following a 150-160 day gestation period, the females give birth to one (occasionally two) pup. She spends several weeks flying with the pup clinging to her chest before it’s finally old enough to be left alone while she forages. She’ll continue to nurse her pup until it’s two or three months old. The male pups become sexually mature at about 15 months of age, while the females generally reach sexual maturity at 19 months old.
Gene Diversity in the Greater False Vampire Bat
In 2006, a group of researchers collected genetic samples of greater false vampire bats from different colonies with the intent of discovering if there was any sign that the population could be in trouble as a result of not enough genetic diversity.
Based on the results the team collected, that while family members do live in the same colonies, there’s nothing to indicate that any inbreeding has taken place. It’s assumed that the males visit different colonies during the breeding season allowing them to spread their DNA around. It also might explain why so many young females stay close to their mother. By living in the same colony with both their mother and their father, the youngsters actually decrease the odds of a genetic slip up happening. The species still has a diverse gene pool which will help ensure their survival provided they don’t start to suffer from habitat loss.
This brings up another concern. As more of the colonies are uprooted and the distance between each colony grows, will the male bats continue to be able to find enough non-related females in order to maintain a diverse genetic make-up or will the increased distance increase the likelihood of inbreeding?
The team also noted that while all greater false vampire bats are one and the same species no matter where they’re geographically located, the bats in, say Sri Lanka, do have some minor genetic quirks that set them apart from those that inhabit the Malay Peninsula. It’s possible, that after a few hundred years, these small changes could alter the bats so much, they evolve into a separate species of bat.
“Greater False Vampire Bat.” Infogalatic. 12 November 2015. Web. Accessed 1 November 2017. https://infogalactic.com/info/Greater_false_vampire_bat
Rajan, K. Emmanuvel. Marimuthu G. “A preliminary examination of genetic diversity in the Indian false vampire bat Megaderma lyra.” 2006. Web. Accessed 1 November 2017. http://abc.museucienciesjournals.cat/files/ABC-29-2-pp-109-115.pdf
Stumpf, J. 2002. “Megaderma lyra” (On-line), Animal Diversity Web. Accessed November 01, 2017 at http://animaldiversity.org/accounts/Megaderma_lyra/