BatHead

Short Guide to the Bats of the (northern) Lesser Antilles by S. Pedersen & M. Morton
Introduction	Roosting	Distribution Table	References
Echolocation	Importance of Bats	Key to Roosts	Authors
Diets	Threats to Bats	Key to Taxa	Research Projects
Reproduction	Species profiles		Update: June 2008

PARTS LIST FOR A BAT
(Diagram: M. Morton)

INTRODUCTION

This introductory guide is designed for lay-scientists and the general public.
It is intended to stimulate interest in these fascinating, secretive animals.

Bats are mammals, they have fur and suckle their live-born young on milk. Worldwide there are over 1200 different species of bat- one-quarter of all mammalian species. They are the only mammals that are capable of self-powered flight upon wings made of skin, supported by the elongated arms fingers of the hand. This living skin has its own supply of nerves and blood vessels.

For the most-part, bats in the region either eat fruit, or they eat insects. There are no dangerous bats in the northern Lesser Antilles, though many can be a nuisance when they live in the ceiling of your home.

Nobody should attempt to handle live bats without proper training: if they do the person may be bitten, or the animal may be seriously injured. Bats are not a threat to anyone and will only bite if you attempt to pick them up. If you are bitten by a bat, wash the wound thoroughly and report it to a doctor, as you should for a bite from any wild animal. Although parts of this guide (including the key at the bottom) tell you how to identify bats in the hand, this is only intended for people who have been trained to do so.

ECHOLOCATION

Bats have perfectly good eyesight, but most bats also use "echolocation" to navigate in the darkness. Echolocation is a kind of biological radar system that involves the bat calling out sounds that are too high-pitched for the human ear to detect. These high-pitched sounds bounce off objects they hit (obstacles, insects, mangoes) and return to the bat as an echo. By listening to how long it takes for echoes to bounce back, bats learn how far away objects are, even if they can't see them with their eyes. In this way bats can chase insects, avoid obstacles, and can avoid daytime predators. They also avoid competing for food with birds that are active during the day.

DIET

Different species of bats eat different foods. In the northern Lesser Antilles, many bats eat only insects, others specialize on fruit (mangos, papayas, figs) and flowers, and one even catches fish and insects that float on the surface of ponds and streams. throughout the region, most of our captured fruit bats are covered in fruit juice and fruit pulp (see our Artibeus-Mango T-shirt logo at left). Elsewhere in the world, bats may eat small lizards, birds, and even a few feed on blood. Not to worry, Vampire bats are not found in the Caribbean, and even where they do occur (Central America), vampire bats feed on animal (not human) blood, usually from birds and livestock. Farmers are often upset by crop damage that they attribute to bats. In fact, birds initiate damage to fruit with their sharp beaks that the bats and their small teeth capitalize upon. Of note, bats do not eat vegetables (usually), but they have been known to eat young pigeon peas before the pods become too difficult to open. In a pinch, fruit bats may supplement their diets with the occasional insect. Many species of bat rely on open bodies of water where they drink whilst flying - skimming over the surface and dipping their mouths in.

Female A. jamaicensis with pup
(Photo A. Hartpence)

REPRODUCTION

Unlike rodents that produce large numbers of young throughout the year, bats throughout the New World tropics typically give birth twice a year. The births are timed to occur in the wet season so that babies are born when there is plentiful food to be found– i.e. when fruit trees are fruiting/flowering. Baby bats are especially vulnerable while they remain in their roosts because they cannot fly for the first few weeks of life. Bats may not breed until their second or third year of life. Mothers often mate immediately after giving birth to the first pup and are pregnant with their second pup while they are suckling the first. The eleven species of bats covered in this guide give birth to one baby at a time though twins are not uncommon. Insect-eating bats typically give birth once a year. These very low reproductive rates mean that if bat populations are reduced (i.e., volcano, hurricane, draught, human disturbance), it may take a very long time for the populations to recover.

(Photo A. Hartpence)

BAT ROOSTS

Nobody should deliberately disturb bats at their roosts, as this could cause them to abandon the roost and their young, or perhaps even scare them away permanently - disturbance should be kept to a minimum. Mother bats congregate to birth and suckle their babies at so-called nursery roosts. If these critical sites destroyed, then the bat population's reproductive output for that year could be lost with them.

Bat feces either contain identifiable seeds, or insect parts (shiny specks of insect “exoskeleton” = hard shiny covering of bugs), whereas rodent feces are chalky or smudgy in consistency. Most bat roosts are very quiet as the bats are usually secretive and do not wish to draw attention to themselves. However, the pig-nosed bat (Brachyphylla) forms large colonies that can be heard and smelled some distance away from the opening to the cave. Most fruit bats roost in small clusters 5-20 animals (Artibeus, Ardops). Free-tailed bats live in large groups (5-5,000: Molossus, Tadarida), whereas the unusual Funnel-eared bat (Natalus) prefers to hang in isolation from cave ceilings.

Bat droppings, noise levels, and clustering behavior can be useful aids in the identification of bat species occupying a roost if the bats are absent or you simply cannot see the bats (see table below).

(photo G. Kwiecinski)

(photo Merlin Tuttle)

IMPORTANCE OF BATS

Bats are the only native mammals known to occur throughout the region - monkeys, rats, mice, agoutis, and mongoose were all introduced to the island by man. In fact, 2 of the 11 species in the area are regional endemics, that is they are not found anywhere else on earth.For this reason alone, these small animals should be protected as an important part of the natural heritage of the Lesser Antilles. However, there are several important reasons for conserving bats.

INSECT CONTROL - Many bats consume huge numbers of insects nightly. The free-tailed bats can eat several hundred insects each evening, and though their presence in your home may be an inconvenience, they are not free-loaders, a small colony of bats easily pays their rent by eating thousands of mosquitoes in the neighborhood each evening - free pest-control.

SEED DISPERSAL - Many fruit bats carry fruit and seeds away from the parent plant thereby helping propagate that species of plant. Studies in Africa have shown that birds drop fruit seeds underneath the tree in which they are feeding where they cannot hope to germinate. Bats, on the other hand, spread their droppings (in flight) over large areas. This wide dispersal of seeds is very useful in the replanting of damaged forests or deforested areas (excessive logging, volcanoes, hurricanes). For some trees, bats are the main agents by which new areas can be reforested.

POLLINATION - Fruit production requires pollination of the flowers on the plant/tree in question. Many bats feed on flowers/nectar, and in doing so become covered with pollen. As they visit the next flower, they transfer this pollen and so pollinate new plants. Many trees that are of economical importance to man are pollinated by bats, i.e., calabash, mango, banana, and cashew. In fact some trees are pollinated ONLY by bats. That is, if the bats become extinct so do the bat-specialized trees. If these trees are lost, then all the other animals that depended on the trees for food or shelter may also be lost, and some of these animals will also be pollinators or seed dispersers for other tree species, and so on. Therefore, the loss of bats from an ecosystem may set-off a devastating cascade of effects throughout the ecosystem - for this reason some bats are called "keystone species", after the keystone that symbolically holds up an entire building.

(photo K. West)

THREATS TO BATS

Despite the valuable roles that bats play in maintaining the health of the natural environment, they are vulnerable to several threats. At roosts, large numbers of bats may congregate; if something destroys the roost then a large proportion of the whole bat population of an area may be lost in a single event. Bats can also be scared away from roosts by human disturbance. Many species have quite particular requirements for roosts. Many species need very humid caves to prevent their delicate wing membranes from drying out, e.g., N. stramineus.

Mother bats congregate to birth and suckle their babies at so-called nursery roosts. If these critical sites destroyed, then the bat population's reproductive output for that year could be lost with them. Bats also depend on a wide range of natural foraging habitats as well to hunt for insects and/or fruit. Damage to these habitats can be catastrophic to the bats, e.g., deforestation (hurricanes, agriculture) will kill important food plants. Over-development of an island may deplete natural springs that are absolutely critical for the maintenance of healthy forested ecosystems. Without the water, the forests die back - without the forests, the wildlife dies out - without neither the forests nor wildlife, tourists will have little reason to visit an island - they might as well stay at home and visit an asphalt covered parking lot in their home town.

Species Profiles The following links will provide a very brief description of some of the more obvious features of each species. A few details might need a bit of explaining for the novice: (1) Body measurements are mainly used by people identifying bats in the hand. The length of the forearm (millimeters) is often used as a measure of bat size. One might imagine that body weight would also be a good measure of body size in bats, however, bats can eat a tremendous amount of food in a very short time, as such, body weights vary greatly and are not a consistent measure of size. Scientific (Latin) names are used to avoid confusion amongst scientists who might otherwise apply "local" names to each type of bat using their own native tongue. As such, the scientific name of each bat consist of two parts - a genus-name and the species name. The first part of a species’ latin name is often abbreviated to its first letter, i.e., Artibeus jamaicensis = A. jamaicensis.
FRUGIVORES	NECTARIVORES	INSECTIVORES	CARNIVORES
Artibeus jamaicensis	Monophyllus plethodon	Molossus molossus	Noctilio leporinus
Artibeus lituratus	Glossophaga longirostris	Tadarida brasiliensis
Chiroderma improvisum		Natalus stramineus
Ardops nichollsi		Micronycteris megalophylla
Sturnira thomasi	Brachyphylla cavernarum	Myotis martiniquensis
		Pteronotus davyi
		Pteronotus parnellii
		Eptesicus fuscus

Bat Fauna of the Lesser Antilles
Photos by Anya Hartpence, Gary Kwiecinski, Peter Larsen, & Scott Pedersen

Artibeus jamaicensis (non stripey)	Artibeus jamaicensis (stripey)	Artibeus lituratus	Chiroderma improvisum
Sturnira lilium	Sturnira thomasi	Brachyphylla cavernarum	Ardop nichollsi
Monophyllus plethodon	Glossophaga longirostris		Noctilio leporinus
Pteronotus parnellii	Pteronotus davyi	Molossus molossus	Tadarida brasiliensis
Natalus stramineus	Myotis martiniquensis	Micronycteris megalotis	Eptesicus fuscus?

IDENTIFICATION KEY: BATS AT A ROOST
RESIDENT		CLUES/OBSERVATIONS
Birds/Lizards		Droppings: hard, white “chalky” bits in/on them
Rats/Mice		Droppings: black, hard (not crumbly), 'smudgy'
Fruit Bats: Artibeus, Monophyllus		Cave + Droppings are dark “splats” (maybe with little seeds) splashed onto walls or appearing in wet piles on floor. Animals grouped in small, tight clusters
Fruit Bats: Brachyphylla		Cave + Loud raucous groups of bats + Droppings are dark “splats” (maybe with seeds) splashed onto walls or appearing in wet piles on floor. Animals grouped in large, tight clusters
Fruit Bats: Artibeus, Monophyllus		Hollow tree/Tree cavity + Droppings are dark “splats” (maybe with seeds) splashed onto trunk or appearing at base of tree. Animals grouped in small, tight clusters
Fruit Bats: Artibeus, Ardops		Canopy/Live tree + Droppings are dark “splats” (maybe with little seeds) splashed onto trunk or appearing at base of tree. Grouped in small tight clusters.
Fishing Bat Noctilio		Shallow cave/Cliff face/Hollow tree trunk + Large droppings (>1cm) + fish scales/insect parts + Smells absolutely horrible! Grouped in clusters.
Freetailed Bats Molossus, Tadarida		Human dwellings/Shallow caves, Rock fissures + Small formed droppings (<1cm) + crumbly with lots of shiny specks (insect parts). Animals grouped in tight clusters.
Funnel-eared Bat Natalus		Caves + Small orange bats hanging randomly across the roof of the cave + spaced apart from each other (>1m)

SIMPLE IDENTIFICATION KEY TO BATS IN THE REGION Moving from left to right through this simplified table should allow you to accurately identify just about any bat in the region north of Guadeloupe and east of the Virgin Islands
SMELL?	TAIL/MEMBRANE?	NOSELEAF?	FUR?	SIZE?	SPECIES
Rancid, oily, fishy-smell	Yes - tail does not extend beyond tail membrane	No	Orange with white stripe down middle of back	Large FA = 83-89mm	Noctilio leporinus
	Yes - tail does not extend beyond tail membrane	No	Orange with buff colored belly	Very small FA = 37-40mm	Natalus stramineus
	Yes - tail extends beyond tail membrane	No	Light brown, ears meet above eyes, wrinkled upper lips	Small FA = 36-39mm	Tadarida brasiliensis
	Yes - tail extends beyond tail membrane	No
	Yes - tail extends beyond tail membrane	No	Dark brown, ears meet above eyes, unwrinkled upper lips	Small FA = 36-39mm	Molossus molossus
	Short tail - no tail membrane	Yes - but round, stumpy	Whitish-yellow to buffy-brown	Large FA = 61-69mm	Brachyphylla cavernarum
	Short tail that sticks our beyond a small tail membrane	Yes - small, heart-shaped	Dark brown fur, bristle-like whiskers encircle noseleaf	Medium FA = 39-43mm	Monophyllus plethodon
	No tail - Narrow tail membrane on inner surface of each leg	Yes	Grayish brown, faint white stripe down middle of back	Large FA = 59-60mm	Chiroderma improvisum
	No tail - Narrow tail membrane on inner surface of each leg	Yes	Medium length brown hair, often faint stripes above eye	Large FA = 60-69	Artibeus jamaicensis
	No tail - Narrow tail membrane on inner surface of each leg	Yes	Long, fluffy, light-brown hair, white tufts of fur on shoulder	Medium FA = 50-54mm	Ardops nichollsi
	No tail - no tail membrane	Yes	Orange shoulder patches (faint)	Large FA = 45mm	Sturnira thomasi

Biodiversity Inventory for much of the Lesser Antilles - 2008
@ indicates new species record for the island since 1994

SCOTT PEDERSEN, PhD
Associate Professor, Department of Biology & Microbiology,
South Dakota State University, Brookings South Dakota 57007
Scott_Pedersen@sdstate.edu, 605-688-5529

Involvement in this guide: Pedersen's research efforts have strayed significantly from his formal training in craniofacial evolution to focus rather on a study that literally fell into his lap — a natural experiment in island biogeography and biodiversity on the small island of Montserrat. Over the last 20 years, Montserrat has been severely damaged by two hurricanes and a series of volcanic eruptions. Variation in the local fruitbat population has accurately reflected the environmental damage caused by each natural disaster, indeed, Pedersen has documented the gain/loss of several species of fruitbat. Pedersen has sampled 8 neighboring islands to serve as natural controls. These small Caribbean islands are unique in that they exhibit high levels of endemism and have a taxonomic composition that is characteristic of more isolated oceanic islands. The effects of major natural disturbances such as hurricanes and volcanoes are so intense that exposed biotas are commonly reconfigured for years to come. Using bats as a model system, the series of natural disasters experienced by Montserrat provide an extraordinary opportunity to observe how the synergistic effects of two types of natural disasters and the associated loss of habitats affect island biodiversity.

MATHEW MORTON
BSc Durrell Wildlife Conservation Trust Les Augrés Manor,
Trinity, Jersey JE3 5BP, British Isles bats@mmorton.mailcan.com

Involvment in this guide: Morton initially developed an interest in bat faunas whilst surveying dwarf crocodiles in West Africa, following this up with bat detector surveys, radio-tracking and bat conservation work in the UK. Over the past ten years he has visited a number of islands in the Eastern Caribbean, focusing on basic inventories of local bat populations, and training local conservation workers, both within government and NGOs, to equip them with the basic techniques needed to monitor bats in their countries and make effective conservation management decisions. This work has often put an emphasis on roost sites as a first phase in conservation management. Education and outreach has also proved important as the ecological roles of bats and their importance to each islands natural heritage has often gone under appreciated. This guide grew out of smaller per-island guides that have been produced over the years as outputs from the capacity building undertaken in these countries.

IMPORTANT NOTICE

Nobody should attempt to handle live bats without proper training; the bat will probably be injured and the person may be bitten. Bats will only bite if you attempt to pick them up; otherwise, they are not a threat to anyone. If you are bitten by a bat, wash the wound thoroughly and report it to a doctor, as you would for a bite from any wild animal.

Although we provide information to help you identify bats in the hand, this is only intended for people who have been trained to do so. We also provide information that may help you identify bats in the roost without handling them. Anyone interested in catching or handling bats should always first make enquiries to the relevant organizations concerned with wildlife conservation on each island. Although bats are not a threat/health risk for people, their roosts can be very hazardous, such as caves and derelict buildings. When visiting such sites, it is best if you take someone along with you and it is important that you should notify someone as to where you are going and when you expect to return.

Nobody should deliberately disturb bats at their roosts, as this may cause them to abandon their young, or could scare them away permanently. Sometimes roosts may be discovered accidentally and it may then be worth trying to identify the bats you see (without catching them) using this guide. Disturbance should be kept to a minimum. New roosts should be reported to organizations concerned with wildlife conservation on each island who are tracking sites on each island that are important to bats.

SOURCE MATERIAL

Adams, R., and S. Pedersen., 1999. The effects of natural disasters on bat populations on Montserrat, BWI: A 20 year history. American Zoologist, 38(5):52A.

Baker, R. J., and H. H. Genoways. 1978. Zoogeography of Antillean bats. Academy Natural Science of Philadelphia Special Publication, 13:563-597.

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Davis, W. D. 1973. Geographic variation in the fishing bat, Noctilio leporinus. Journal of Mammalogy, 54: 862-874.

de la Torre, L., and A. Schwartz. 1966. New species of Sturnira (Chiroptera: Phyllostomidae) from the islands of Guadeloupe and Saint Vincent, Lesser Antilles. Proceedings of the Biological Society of Washington, 79:297-303.

Dolan, P. G. 1989. Systematics of Middle American mastiff bats of the genus Molossus. Special Publication of the Museum, Texas Tech University, 29: 1-71.

Fenton, M. B., et al. 1992. Phyllostomid bats (Chiroptera: Phyllostomidae) as indicators of habitat disruption in the Neotropics. Biotropica, 24:440-446.

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