KINDS OF BATS: SMALLEST, BIGGEST, VAMPIRE BATS

KINDS OF BATS

bumblebee bat

There are more than 1,400 species of bats in the world, which is almost 20 percent of all mammal species. Bats can be found on almost every part of the planet, except in extreme deserts and polar regions

There are two main kinds of bats: insect-eating bats and fruit-eating bats. There are about 700 species of insect-eating bats. The biggest is about the size of a small rat. The smallest, the high-nosed bat of Thailand, sometimes called the bumble bat, rivals the pygmy shrew as the smallest of all mammals. Both the shrew and the bat are around four centimeters long and weigh two grams.

Fish eating bats swoop down out of the sky like an eagle and capture their guppie-size prey with one claw, then while still flight place the fish in their mouth, kill it with a couple of chomps, and then store the fish until later.

Websites and Resources on Animals: Animal Diversity Web animaldiversity.org ; BBC Earth bbcearth.com; A-Z-Animals.com a-z-animals.com; Live Science Animals livescience.com; Animal Info animalinfo.org ; Encyclopedia of Life eol.org , a project to create an online reference source for every species; World Wildlife Fund (WWF) worldwildlife.org the world’s largest independent conservation body; National Geographic National Geographic ; Endangered Animals (IUCN Red List of Threatened Species) iucnredlist.org ; Biodiversity Heritage Library biodiversitylibrary.org

Websites and Resources: Bat Conservation Trust bats.org.uk ; Bat Conservation International batcon.org ; Wikipedia article Wikipedia ; Merlin Tuttle, the founder and president of Bat Conservation International.

Fruit Bats

Fruit bats are much larger than insect-eating bats. For the most part they eat food other than fruit and lack the sophisticated navigation system of insect-eating bats. Instead they rely on sight and their large eyes.

The brains of fruit-eating bats and insect-eating bats are so different that some scientist believe they descended from a hole different set of animals. Molecular and genetic evidence indicates the two groups share a common ancestor. Fruit bats likely branched off from insect-eating bats some time ago.

Some species feed almost exclusively on plant species that rely on them for pollination, These include bats that feed on cacti, mangroves, and wild eucalyptus. Many of the plants produce flowers the open at night and are white making it easier for the bats to see them and are clear of twigs and leaves so the bats don’t tangle their wings on them. The plants also tend to produce a large quantity of nectar that bats can sense from a long distance away.

Because there is relatively little nutrition in the fruit and so much water bats have to eat a whole lot of fruit. A group of fruit bats have been known to descend on an orchard and destroy a fruit farmer entire crop overnight.

Bumblebee Bat — World’s Smallest Bat and Arguably the Smallest Mammal

The Kitti's hog-nosed bat (Craseonycteris thonglongyai), also known as the bumblebee bat, is the smallest species of bat and arguably the world's smallest mammal by body length (the Etruscan shrew is regarded as the smallest by body mass). The only extant member of the family Craseonycteridae, it lives in western Thailand and southeast Myanmar, where it occupies limestone caves along rivers. It is regarded as a near-threatened species. [Source Wikipedia]

Kitti's hog-nosed bat is about 29 to 33 millimeters (1.1 to 1.3 inches) in length and weighs two grams (0.071 ounce). The main competitors for the title of the world's smallest mammal, depending on how size is defined, are small shrews. The Etruscan shrew may be lighter at 1.2 to 2.7 grams (0.042 to 0.095 ounce) but its body is longer, measuring 36 to 53 millimeters (1.4 to 2.1 inches) from its head to the base of the tail. There are also very small shrews in Japan and other places

The Kitti's hog-nosed bat has a reddish-brown or grey coat, with a distinctive pig-like snout. Colonies range greatly in size, with an average of 100 individuals per cave. The bat feeds during short activity periods in the evening and dawn, foraging around nearby forest areas for insects. Females give birth annually to a single offspring.

Although the bat's status in Myanmar is not well known, the Thai population is restricted to a single province and may be at risk of extinction. Its potential threats are primarily anthropogenic, and include habitat degradation and the disturbance of roosting sites.

Flying Foxes

Giant Golden-Crowned Flying Fox

Flying foxes are the world’s largest bats. They are distinguished from other kinds of bats in that, for the most part, they use their eyes not echolocation to locate objects. Flying foxes get their names from their foxy faces and some recent neurological and morphological studies have shown that they may be flying primates.

Flying foxes are fruit bats. They are not as big as foxes but they have fox-like faces and reddish fur. There are over 200 species of them scattered across Asia, Africa and the South Pacific — but not in the Americas and Europe. They are most common in tropical Asia, Madagascar, Australia and the South Pacific islands. Southeast Asia is home to many species of flying fox. The Malayan flying fox is the world’s largest bat. It has a body the size of a house cat and wingspan up to five feet.

Flying foxes are dark grey, black or brown in color with a yellow or tawny mantle. Their muzzle is long and slender like a fox’s; the hair on their bodies may be up to a foot long; and their fingers may be as long as their arms. Tendons in their feet allow them to hang upside down without effort. They need muscles to let go. They are quite agile climbing through trees but they can’t walk or sit.

Indian and Giant Golden-Crowned Flying Foxes — the World’s Largest Bats

The giant golden-crowned flying fox (Acerodon jubatus), also known as the golden-capped fruit bat, is recognized at the world’s largest bat. A species of megabat endemic to the Philippines, it weighs up to 1.4 kilograms (3.1 pounds). The Indian and great flying fox can weigh more but the giant golden-crowned flying fox has the longest documented forearm length of any bat species at 21 centimeters (8.3 inches). Its wingspan of 1.5–1.7 meters (4.9–5.6 feet). [Source Wikipedia]

The Indian flying fox (Pteropus medius) and great flying fox (Pteropus neohibernicus) have a maximum weight of 1.6 kilograms (3.5 pounds) and 1.45 kilograms (3.2 pounds) respectively. The great flying fox has a slightly shorter forearm length and wingspan. Its wingspan is up to 1.5 meters (4.9 feet). The giant golden-crowned flying fox is somewhat dimorphic, with males slightly larger than females in many cranial and external measurements.

The giant golden-crowned flying fox is primarily frugivorous, consuming several kinds of fig and some leaves. It forages at night and sleeps during the day in tree roosts. These roosts can consist of thousands of individuals, often including another species, the large flying fox. Not much is known about its reproduction; it gives birth annually from April through June, with females having one pup at a time. Predators of the giant golden-crowned flying fox include raptors such as eagles, the reticulated python, and humans.

The giant golden-crowned flying fox is an endangered species primarily due to deforestation and poaching for bushmeat. Since its description in 1831, three subspecies of the giant golden-crowned flying fox have been recognized, one of which is extinct. The extinct subspecies (A. jubatus lucifer) was formerly recognized as a full species, the Panay golden-crowned flying fox.

Vampire Bats

vampire bat feeding on a pig

Vampire bats drink blood and weigh less than an ounce. They feed primarily on cattle and usually circle their prey several minutes before landing. They are not found in Transylvania in Romania. Rather the live in tropical Central and South America. Several rainforest people regard them as delicacies.

"Most agile of bats," bat expert Alan Novick told National Geographic , "the vampire can walk like an ape, scurry like a mouse, or jump like a frog, and stalk its prey on foot. But the bat rarely attacks man." They supposedly make good pets. Novick had one named Gwendolyn that like to hang contentedly from his breast pocket.

Vampire bats have an efficient anticoagulant in their saliva. They drink about a tablespoon of blood by puncturing a shallow wound into the victims skin with is sharp fangs and then lapping up the blood with its tongue. The secret to vampire's success is stealth. The bats have a "light touch and a quick getaway." Most cows never know what hit them. Vampire bats are a problem in some areas because they carry rabies and they can attack individual animals so many times that some livestock becomes weak and less productive.

Pet vampire bats can be trained to take blood from a dish. People live in areas where they are common say the bats bite animals but not people and scoff at stories about people having problems with them. The famous animal behaviorist Konrad Lorenz (of "imprinting" geese fame) once tried to get two vampire bats to bite but said they were too shy to do it.

In the rainforest some people complain about them. "More than once," says adventurer W. Jesco von Puttkamer," asleep in my hammock, I have been awakened by stealthy movement on my toes and found a vampire bat walking about looking for an opening in my blanket so it could make a meal of my blood." [Source: W. Jesco von Puttkamer, National Geographic, January 1979]

Serotine Bats — First Mammals Known to Mate Without Penetration

A video has revealed that the serotine bat (Eptesicus serotinus), a fairly large Eurasian bat with large ears, may be the first mammal known to mate without using penetration. Katie Hunt of CNN wrote: Serotine bats mate by touching their genitals together. The male bat uses its penis more like an arm to move a protective membrane away from the female bat’s vulva, according to a study published in November 2023 in the journal Current Biology. [Source: Katie Hunt, CNN, November 22, 2023]

Thanks to the efforts of a Dutch bat enthusiast who set up 18 video cameras in a church in the Netherlands that was home to a roosting colony of serotine bats, Nicolas Fasel, a bat specialist at the University of Lausanne in Switzerland, and his colleagues were able to analyze 93 mating events in detail. Video of an additional four mating events involving the same species came from collaborators at a bat rescue and rehabilitation center in Ukraine. “You can really see the copulation and see that the penis is not going inside,” Fasel said.

The footage showed that half of the recorded mating episodes lasted less than 53 minutes, while on one occasion a pair of bats stayed together in a copulative embrace for more than 12 hours. The behavior is similar to a “cloacal kiss,” a way of mating used by many birds.

What Fasel and his colleagues observed on the videos may solve a long-standing puzzle about the reproductive biology of this species of bat, and others in the same family. The male bat’s penis is around seven times longer than its female counterpart’s vagina, and it has a heart-shaped head that is seven times wider than the vaginal opening. These are features that appear to make penetrative sex difficult, if not impossible, Fasel noted.

Teri Orr, an assistant professor and specialist in bat reproductive systems at New Mexico State University, said she was initially “astonished” to see that males may be using their genitalia as a “copulatory arm” and “maybe transferring sperm much as birds do.” Orr was not involved with the study. “Bats use their uropatagia (tail membranes) in many unique ways such as fishing nets, to catch pups during birth and so forth and thus they are useful in many ways but perhaps an impediment during mating,” Orr said.

“I agree that the male of this species may use his genitalia to navigate the female’s tail but there are some key things to be sorted out,” she added via email. “For one: how is the sperm transferred exactly and for another what is the female doing in this pair?” Study coauthor Susanne Holtze, a senior scientist at the Leibniz Institute for Zoo and Wildlife Research in Berlin, acknowledged that they had not been able to definitively prove the transfer of sperm from male to female bats and said that will be a focus of future research. “It’s a bit of an open question how their semen really gets into the female reproductive tract. It might be that there’s kind of suction involved. We cannot fully answer this mechanism,” she said.

Image Sources: Wikimedia Commons

Text Sources: Mostly National Geographic articles. Also David Attenborough books, Live Science, New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Natural History magazine, Discover magazine, Times of London, The New Yorker, Time, Newsweek, Reuters, AP, AFP, Lonely Planet Guides, Compton’s Encyclopedia and various books and other publications.

Last updated November 2024