Fruit Bats

 



Only the Order of Rodents has more species than Chiropetera, which is the Order for bats. These remarkable animals can be found as essential parts of ecosystems in many warm and temperate climates with the exceptions of a few places including some extremely remote islands. Bats are normally not found at altitudes above the tree line. There are two distinct Sub Orders of bats with 18 families, 187 genera and nearly 1000 species categorized today. This is nearly 25% of all living mammal species today. Bats are true flying mammals, quite differentiated from the 'gliding' mammals, two of which are covered in this text. Bats have highly specialized diets as follows:

No bats may be kept in private ownership due to a ban by the Center for Disease Control. All bats in captivity must be permitted!!!

  • Insectivorous - those that eat insects, spiders and scorpions - About 70% of all species of bats
  • Frugivorous - Those that eat fruits and flowers - Some species also eat nectar and pollen.
  • Nectarivorous - Those that eat nectar and pollen - Only a few species that feed exclusively on nectar and pollen
  • Carnivorous - Those that eat small mammals, reptiles and amphibians - Only a few species
  • Piscivorous - Those that eat fish - Only a few species
  • Sanguivorous - Those that feed on the blood of warm-blooded animals including birds. Only a few species (All in the Americas)
    • Insectivorous and frugivorous, nectarivorous bats are highly beneficial to mankind and the ecosystem.

    Tiny insectivorous bats can catch 600 mosquitoes in an hour. There are over 20 million Mexican free-tailed bats living in Bracken Cave in Texas. They are reputed to eat 250 tons of insects every night. Bats eat beetles, moths, flies, mosquitoes, cockroaches, termites, flying ants, crickets, katydids, and many other insects. In addition to insects, they also eat spiders and scorpions. About 70% of all the bat species are insectivorous.

    Fruit and nectar eating bats may also consume flowers and pollen with a few insects thrown in for good measure. Some species specialize on nectar and pollen. In the process of consuming large volumes of fruits, nectars and pollens the bats pollinate flowers and disperse seeds. There are some plant species whose seeds will not germinate unless they pass through the gut of a bat or bird.

    Bats vary in size from 1" to 16" in body length, with wing spans from 6 inches to 6 feet. Weights range from less than 1/20th of an ounce to 3.5 lb. Most bats have soft, silky fur on their body and naked wings. There is one Genus of naked bats, Cheiromeles.

    Bats first appeared (as evidenced by fossil records) about 60 - 70 million years ago. Examination of fossil remains from 50 million years ago show similarities in basicranial features as those of today's bats that have echo-location capabilities. Despite bats' diverse forms and diets, it is probable that all bats have a common root ancestor. Some scientists agree that bats are related to gliding lemurs and are evolved from tree-dwelling insectivorous ancestors of prosimians and monkeys. Some of the smaller bats are thought to have evolved from shrew-like ancestors. Bats are taxonomically divided by structure rather than feeding habits because some bats overlap more than one type of food category.

    Many legends and superstitions surround bats. Because of their diverse forms, they have been named, in native languages, descriptively such as butterfly mouse, flying mouse, flying fox, hammer-headed fruit bat, little flying cow, dog-faced bat, shaggy-haired bat, ghost bat, mustached bat, , leaf-nosed bats, flower-faced bat, horseshoe bat, big-eared bat, sword-nosed bat, long-tongued bat, yellow-shouldered bat, and many more.

    Bats are uniquely separated from all other living mammals by their ability to achieve sustained flight. In ancient times there were flying saurians (reptiles) that eventually became extinct. Today, bats are the only living creatures besides insects and birds that have the capability of flight. The bats have a flight membrane that stretches from the body, legs, tail and through three elongated fingers. The former flying reptiles had a flight membrane but only one elongated finger. Birds, on the other hand, the 'finger' is greatly shortened, with a very small membrane, and the wing itself is created from a system of long and overlapping feathers. All of these three vertebrates, however, have strong flight muscles.

    A large portion of the rest of the information on bats in this FAQs will deal with frugivorous bats of the species Rousetteus aegypticus.

    Taxonomic Classification
    Order: Chiroptera - Bats - 17 Families and nearly 1000 species
    Sub Order: Pteropodidae - Old World Fruit Bats
    Genus: Rousettus - 9 Species
    Species: aegyptiacus - Found in Egypt, Turkey, Cyprus, Pakistan, Arabia, and most of Africa South of the Sahara.


    Range and habitat
    Bats are found in most warm parts of the world, with the exception of some very isolated tropical islands. Bats rarely are found at altitudes that are above the natural tree line. They are found somewhere on all of the continents except Antarctica. In colder temperate zones, the bats may hibernate during cold periods. Their incredible capability for flying long distances has enabled them to reach many remote islands. One genus, Myotis is the most widespread of all and in fact, may be the most widespread of any mammal. Many species are unique to a particular region and have highly specialized diets and environmental requirements. Bats roost in trees, caves, tombs buildings, under rocks and even under leaves in the case of the tiny hog-nosed bat. The majority of bats are distributed in the warmer regions of the world, however.
    Food in the wild
    Fruit Bats
    Fruit and nectar eating bats are both an integral part of the ecosystem in their native rain forests and a significant ally to local agriculture. In their search for nectar and ripe fruits, they are one of the most important pollinators in many areas for bananas, figs, dates, mangoes, agave plants, many cactus plants and other fruit bearing plants. As they consume the ripe fruits, they also become directly involved in crucial seed dispersal and subsequent propagation of those types of plants. The relationship between these plants and the bats are uniquely symbiotic and critical to the survival of both. Some insect matter and pollen are consumed as a matter of course while eating fruits and nectar. These bats are usually larger than most of the insectivorous species.
    Insectivorous Bats
    Insect eating bats consume millions of insects every evening. A single bat can consume over 500 mosquitoes in an hour and 100 bats will consume 2.5 lb. of insects in a single night. In areas where insectivorous bats are common, farmers and the local population are protected from hoards of insects that are the bats daily fare. Bats are adept in catching insects in flight. The bat has the amazing ability to cup the tail portion of its body forward and envelope its wings around the insect prey, even while flying for an instant if it is apparent that the prey might escape. The bat is able to immediately right itself and continue on its way.
    Bats with other diets
    Some bats have highly specialized diets and have developed physical characteristics necessary for that diet. Certain nectar eating species have elongated muzzles and very long tongues to enable them reach into flowers. Another species has extra long feet which are dipped into the water surface to catch small fish. Some species prefer small mice and other vertebrates like frogs and small lizards. There are also, three species of true vampire bats in the new world. The inflict a small wound on a sleeping mammal or bird and feed on its blood.
    Characteristics
    Bats have bodies adapted to allow for their aerodynamic life style. Their bodies have the center of gravity near the chest. Their body is conical and slim. Their shoulders are very muscular and their neck not visually discernible. The bones of the forearm and fingers are extremely elongated with the patagium (flight membrane) stretched between them and the and the body. Claws on the thumb and feet aid the bat when moving along a surface. They have specialized tendons in their legs for grasping prey, food and resting surfaces. Most fruit bats have either a vestigial tail or none at all. Most insectivorous bats have a tail of some sort.
    Social habits
    Depending on the species, bats are usually found in large groups. Many species cluster together in tight bunches. In some species the mother will leave her baby at the roost when she searches for food. In other species, the baby clutches to the mother's fur with its milk teeth and claws for up to 4-5 weeks after birth.
    Personal Habits
    Bats groom themselves with their long tongues and back feet. They are able to comb their fur with their toes and can reach any portion of their back or head with their feet. Normally, bats rest hanging from their back feet, head pointed down, wings folded around themselves. Youngsters hang on to their mother's fur with their toes and curved milk teeth. The mother bat folds her wings around her youngster when she is at rest. The baby also hangs head down when the mother is at rest. Bats urinate and defecate during flight, however, if the need arises while they are roosting it could be quite messy if they did not change positions. We have documented bats roosting in a normal 'upside-down' position, hanging by their hind feet, with the wings folded around their body. They lift the wings and head to the upright position, take hold of the roosting structure by their hook-like thumb, let go with the back feet, and the body pivots downward for defecation and urination. When ! finished, they return to the normal roosting position.
    Longevity
    Healthy bats in the wild live from five to ten years. Captive bats have lived up to 30 years in some zoological gardens.
    Enemies
    Enemies in the wild include various raptors (birds of prey), some snakes, various native predatory animals and humans. Bats, especially fruit-eating species, are considered a delicacy in various tropical islands and Asian countries. Therefore, humans are probably the number one enemy of bats. Humans also contribute to the demise of many bat populations by the introduction of fertilizers, pesticides and other chemicals as well as deforestation.
    Active and dormant periods
    Bats are active at different times of the day and night depending on their species and the availability of food. The majority of insectivorous and carnivorous bats are active from dusk to dawn. These animals create quite a stir in some localities because every bat begins its night flight at a precise moment as darkness falls.
    Physiology Normal Values
    Fruit bats are able to maintain normal body temperatures of 37 degrees C. (98.6 degrees F) when the ambient temperature is between 41 and 95 degrees F. At less than 70 degrees F. The animal may shiver to increase metabolic heat. At higher temperatures, the bat may pant, extend and fan their wings. In some instances the bat may salivate and lick their wings to facilitate cooling. I appears that the standard blood measurements for bats have higher values than other similarly sized mammals. The mean hematocrit values are 51.2 to 52.7 for certain fruit bats and hemoglobin concentration of 16.9 gm/dl.
    Structure and appearance Dentition Young bats have about 22 'milk teeth' that are curved to help the baby hold on to the mother's fur. Adult dentition numbers between 20 and 38 depending on the species. In Rousettus, the dentition formula is as follows for a total of 34 teeth:
  • Incisors: top 2 Bottom 2
  • Canines: top 1 Bottom 1
  • Pre-Molars: top 3 Bottom 3
  • Molars: top 2 Bottom 3

    • For those of you not familiar with dentition formulas, these figures represent one side of each of the top or bottom. This is multiplied by two to get the total number of teeth, which is 34. This varies in mammals and the major difference lies in the number of incisors and various molars. Bats have a total of 4 incisors on the top, and 4 on the bottom. Most placental mammals have six or less on top or bottom. This of course, does not include certain ungulates which have NO incisors on top. Their incisors are tiny with moderately long canines. The molars are smooth, low and long, adapted for a soft diet. Their palate has ridges that the food is crushed against by the tongue. The tongue is moderately elongated to assist in gathering nectar and grooming. Teats
    Females have two teats below the approximate area of the armpits.
    Senses
    Fruit bats locate their food by their sense of smell. The fruit bats are one species of bat with good eyesight and often use this sense also for detecting fruit or flowers. They have highly sensitive ears that can detect sounds well out of the range of human hearing. Bats do not use their sense of sight for nocturnal orientation, but instead use echolocation. These bats emit sounds from their mouth which are reflected back to the bat's ears and help it to avoid obstacles. Of the fruit-eating bats, only the rousettus and one or two other species use echolocation.
    Wings
    The bats' wings are the unique adaptation that separates them from all other living mammals. The wings are forelimbs that have been modified. The forearm bone is elongated and extends away from the body at the upper arm. Each wing has five digits. The first one, which is the thumb, is very short, and has hooked claw. This is used for grasping surfaces. The second digit is a short distance from the wrist, slightly inside the wing membrane and has a small hook on Egyptian fruit bats. The third digit extends to the end of the wing. Digits four and five form a "V" and extend to the bottom edge of the wing. The wing membrane is composed of several segments between the various fingers, arm bones, body and tail. The wing membrane is composed of two layers of skin with a small amount of connective tissue between them and no tissues other than nerves and blood vessels.
    Skin, Color and Hair Coat
    Most bats are dusky gray or brown in color. Certain species are decorated with various shades of rust, gold or yellow fur. The fur is normally soft and dense. Certain species also have stiff hairs around the neck areas and are associated with cutaneous glandular formation.
    Eyes
    All bats are able to see, however, the old world fruit bats (flying foxes) use their vision more than other species to locate their food source.
    Ears
    Bats have a wide variety of ear types and sizes. The fruit bats have small fox-like ears that are upright. Their ears have the ability to pick up sounds well out of the range of human hearing.
    Feet & legs
    The rear feet of the bat have five curved toes and claws. These sharp claws enable it to grasp and climb various surfaces. The front limbs are modified into wings. The thumb has been modified into a hook that is used to grasp during climbing.
    Genital Area
    Males
    In Rousettus bats, the testes descend into the scrotal sac just prior to breeding season. During the balance of the year, they are carried abdominally and not visible. The penis is composed of tissues and in structure similar to primates.
    Female
    Females have a reproductive tract not unlike other placental mammals. It consists of two uterine horns joined at the cervix. There are two ovaries.
    Sexing Bats
    During breeding season and immediately prior to it, the male's testicles descend into the scrotum.
    Communication
    Bats are very vocal and use their voices to communicate with each other and to exhibit their emotions. The rousettus fruit bats have a variety of squeaks, clicks, and chirps that can be quite interesting to listen to when they are feeding and resting. They can become quite quarrelsome in vying for a favorite roosting place or piece of fruit. Often times, a bat that is resting and content (but not asleep) will vibrate its whole body. I like to compare this to purring in a cat.
    Metabolism
    Bats can hibernate during cold weather. When doing so, they reduce their metabolism and consume less that 1% of the normal amount of oxygen. Sleeping bats also reduce their metabolism and body temperature and consume 10% of the normal amount of oxygen. Upon awaking, normal metabolism returns.
    Echolocation
    Most fruit bats do not use echolocation, however, Rousettus aegyptiacus is one of a handful of fruit eating bats that do have the ability to use this method of ultrasonic orientation.
    Diet
    The following diet is for one day for 25 Rousettus aegypticus bats. It is divided in two meals per day and fed in several dishes, at 9:00 am and 4:00 PM, daily. We have a platform mounted on a post about 6 feet high upon which we place the dishes. We find that pizza pans work very nicely. Fruit should be cut in relatively small pieces and placed in several locations so that the more aggressive feeders to not monopolize the food. Bats that are allowed to fly, do not tend to become obese so we always put more food than is necessary. Bats tend to eat more some days than others with temperature and season affecting their consumption. In general, small fruit bats should be fed all that they will eat. They can eat up to 1/2 their weight in fruit per day. Fruit bats should not get too much vitamin D and must get the proper amounts of calcium to prevent brittle bones. When calcium deficient, their bones will break easily. Fruits should be ripe and sweet. It is not necessar! y to peel fruits, and in fact the bats seem to enjoy scraping the skins clean.

    When their plates are empty, bats that are still hungry will go to the floor of the enclosure to search for unfinished portions of fruit. This indicates that it is important that there are no toxic substances, i.e. chlorine bleach, detergents, insect sprays, etc. within reach of these bats or the dropped fruit. Unless grossly overfed, the bats will not leave one speck of fruit.
  • 1 can ZuPreem Primate Diet cut in small chunks*
  • 10 medium bananas peeled and sliced
  • 4+ cups of other diced fruit - cantaloupe, apples, pears, plums, grapes, tomatoes, cooked sweet potato, cooked carrots, papaya, avocado, berries, oranges etc. All fruit must be ripe and sweet. We do not recommend citrus of any type.
  • 1 cup chopped leafy greens (leaf lettuce, collards, celery, mustard, endive, watercress, etc.)
  • 1 tsp. Vitamin/mineral mix** sprinkled on top of fruit
    • **Vitamin/mineral mix
  • 12 oz. Sterilized bone meal (25% Calcium, 12% Phosphorus
  • 8 oz. Dicalcium phosphate (18% Calcium, 21% Phosphorus
  • 2 oz. Limestone (38% Calcium)
  • 10.5 oz. Multivitamin powder (Theralin)
  • 2 oz. Vitamin E Powder that is 50 IU/g
  • Fresh water

    • Fresh water. Nekton Lorikeet nectar mix can be used also if desired or canned fruit nectars such as guava, peach, pear, etc.

    *Some persons have been successful substituting 'soft' dry dog food such as Ken-L Ration Burger for the canned primate diet.


     

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