Bats of Costa Rica:
An Introduction to Ecology and Diversity
o Intro Slide
 Welcome the group and introduce yourself.
 This talk is designed to provide an introduction to bats’ general characteristics,
adaptations, and ecology, and then to discuss some of the major bat families found
in Costa Rica.
 Bats are extremely important to ecosystem health and function both here in the
tropics, as well as in temperate habitats, yet they are a vastly understudied and a
largely misunderstood group of animals. (What do you all think of bats? Do you like
them? Do they scare you?)
o Photo: Commissaris’s long-tongued bat (Glossophaga commissarisi) feeding
on the flower of the Calabash tree (Crescentia cujete)
o What is a bat?
 A nocturnal, flying mammal! Like a flying rodent? Despite popular belief (they are
sometimes called “flying mice”), they are actually more closely related to us, the
primates, than they are to rodents. (Evidence suggests that primates and bats
belong in a group called Archonta, along with flying lemurs and tree shrews).
 Bats belong to the Order Chiroptera, one of about 27 orders in Class Mammalia.
Chiroptera means “hand-wing.”
o Mammal Diversity
 This pie chart shows the species distribution among mammalian orders. As you can
see, Chiroptera is the second most diverse order of mammals, second only to
Rodentia (rodents, such as squirrels, agoutis, mice).
 About 20% (1/5) of all mammal species are bats; this equals about 1200 species, out
of about 5,500.
(About 2200 spp of rodents = about 40%)
 Of these bat species, the majority is found in the tropics, with diversity actually
decreasing away from the equator (a typical ecological pattern called the “latitudinal
diversity gradient”).
 So, what do you think has facilitated this impressive diversification? What special
adaptations have bats evolved?
o Why are bats so diverse?
o The abilities to fly and to echolocate have allowed them to exploit a unique nichethe nighttime sky.
o Bats have evolved adaptations for a variety of roost sites and feeding habits, which
has reduced competition between species.
o Bats basically fulfill the same ecological niche as birds do during the dayeating insects, dispersing seeds, etc.
o Flight
1





Bats are the only mammals with true flight; others, such as flying squirrels, have the
ability to “glide,” but they cannot sustain powered flight.
The evolution of bat flight likely began in an arboreal mammal that glided from tree
to tree. This behavior would be advantageous for a number of reasons, including
energy conservation (from not having to run up and down tree trunks), safety from
ground predators, and the ability to capture flying insects. Thus, it is likely that
natural selection favored larger skin membranes, which eventually became full
wings.
As you can see in this diagram, bat wings are structurally very different from bird
wings. They have undergone lengthening of the forearm, hand bones (metacarpels),
and finger bones, which have two thin, flexible skin membranes stretched across
them. This membrane is covered in microscopic hairs that can sense airflow.
Here’s a video of the flight pattern of a bat, and you can tell that the wings are highly
articulated; they contain about 24 independent joints, which gives them greater
maneuverability than other flying animals. They can actually make 180-degree
turns in a distance of less than half a wingspan! Further, the large surface area and
the elasticity of the skin membrane enables them to extend them in ways that
generate more lift and fold them in ways that create less drag than is experienced
with the more rigid wing structure of birds and insects. Thus, many scientists say
that the flight of bats is the most efficient in the animal world.
Bats also have porous (not hollow) bones, and very small pelvis bones, which serves
to make them lighter for flight.
o Anatomy of a Bat
 Point out the thumb and other four fingers. The first finger, or thumb, has a claw
that is used for climbing (e.g. up tree trunks).
 Notice how the legs are rotated 180° compared to humans, with the “top” of the
knee on the dorsal, or back, side (i.e., the legs bend toward the back). This
adaptation allows them to hang upside down in the direction that they will fly,
but also enables them to make a basket out of the tail membrane (called the
“uropatagium”), which is used for catching insects in flight. Though, the size of the
uropatagium differs between species and is sometimes completely absent.
 Also, this diagram is missing the reproductive parts, which, as expected, would be
above the tail membrane, and are similar to the genitalia of other mammals.
o Life History
 Given their small body size, bats have an unusually long life span and slow
reproduction and development (collectively, this is referred to as a slow “lifehistory strategy,” which is generally associated with large animals, such as
humans).
 Though ages differ between groups, some bats have been found to live up to 38
years! (a Brandt’s bat, Myotis brandtii)
 They have a gestation period of at least 3 months, after which they generally only
give birth to one, or occasionally two babies, called “pups”. In Costa Rica, most pups
are born at the end of the dry season or beginning of the wet season. Some species
2




will have a second pup in the middle of the wet season. (Though not all females
reproduce every reproductive season.)
When born, pups weigh between ¼ and 1/3 of their mother’s weight! They have
hook-like “baby” teeth (that they later replace with adult teeth), which allow them
to grab onto their mother’s nipples. She will feed them for at least the first 6-8
weeks, after which they are able to fly.
Bats have extremely varied roosting habits. Though some live solitarily, more often
they live in social groups/ colonies. These can range from a couple of bats to tens of
thousands.
The most common social structure for colonial bats is a harem, which contain many
females and young with a few males (“resident males”) and a separate group of
“nonresident males”.
Social complexity (some live together for over 10 yrs) resembles that of highly
intelligent animals.
 Photo: Brazilian free-tailed bat (Tadarida brasiliensis)
o Echolocation
 Alongside nocturnal flight, bats evolved the ability to echolocate, which is essentially
a way to “see” using sounds.
 Bats emit sonar waves (some emit the vocalizations from their mouth, while others
emit it through their nose), which then bounce off of objects in the environment. The
returning echoes are analyzed by the bat’s brain, similarly to the way our brains
interpret visual input, essentially creating a “sound-picture” of the environment.
 Bats’ ears also contain unique folding patterns and they have elongated tragus/
specialized inner ears, which aid in the reception and analysis of the sound waves.
 Bats can also adjust the frequency of the sonar waves to develop a more complete
picture (higher frequency waves detect smaller objects, such as insects, but don’t
travel as far as lower frequency waves). Some can detect objects as fine as a human
hair!
 For most species, the calls are at too high a frequency for humans to hear (11kHz to
212 kHz); here is an example of bat calls, but the frequency has been lowered to fall
within our hearing range.
 Because they are unique to each species, these echolocation calls are also used by
researchers to help identify flying bats using sound detector and analysis
technologies (such as Ana Bat).
 Echolocation ability is not unique to bats (who else? Whales and dolphins; shrews
and tenrecs; the oilbird and swiftlets (cave-dwelling bird species)), but they do have
one of the most sophisticated systems.
 So, the combination of these two unique mammalian capabilities- flight and
echolocation- has given bats the ability to exploit the night sky.
o Bat Taxonomy
 I mentioned at the beginning that all bats are in the mammalian Order Chiroptera,
and this is divided into two major groups: the Megachiroptera and the
Microchiroptera.
3

However, bats are actually not well represented in the fossil record (thin bones,
adapted for flight, do not preserve easily; they tend to only find the jaws). Thus, the
evolutionary history is not fully understood. Most scientists agree that bats arose
from one evolutionary line; some are actually now contending that the two lines
arose independently, though evidence for this is still unclear.
o Megachiroptera
 The Megachiroptera, also known as the Fruit bats, are only found in the Old World
(that is, Africa, tropical Asia, and Indo-Australasia).
 This group includes the world’s largest bats, called the Flying Foxes, which can have
a wingspan up to 6 ft. and live in the Philippines.
 These bats exclusively eat plants (i.e. fruit, flowers, nectar, and pollen), and thus lack
echolocation, but have good eyesight, which helps them find fruits.
 All Megachiroptera are in one Family- Pteropodidae.
 However, all of the bats in Costa Rica belong in the Suborder Microchiroptera…
o Microchiroptera
 The Microchiroptera, also called the echolocating bats, are found in both the Old and
the New World, on every continent except Antarctica, and on many isolated islands.
 There are 1046 species organized among 16 different families (much higher
diversity than the Megachiroptera). These bats all have some ability to echolocate,
and probably evolved from an insectivorous bat.
 However, over time, they have experienced extensive speciation. Especially in
tropical regions, bats have undergone adaptive radiation, which basically means
that they quickly diversified to fulfill a variety of niches. Today, Microchiroptera
have a wide variety of feeding habits: many still eat insects, but others eat fruit,
insects, other bats, fish, and even, in a few cases, blood.
o Anatomical Adaptations: Dentition and Wings
 The faces and dentition (teeth) of the bats have evolved into forms that are well
suited for eating these particular foods.
 From these photos of facial structure, what do you think each of these bats eats? 1)
nectar; 2) insects; 3) fruit.
 As you can see, the nectar-feeders have a long snout; they also have reduced or even
absent lower incisors, which allows them to extend their long tongue into tubular
flowers. Insectivorous bats usually have pointed, W-shaped molars that can bite
through and chew on insect exoskeletons, while fruit-eaters have flattened molars
to chew up fruit flesh.
o Anatomical Adaptations: Wings and Tail Membranes
 Further, the different wing shapes and sizes of different species are ideal for their
particular flying and feeding habits. For example, aerial insectivores tend to have
long, narrow wings that facilitate fast, agile flight. Species that eat fruit, blood, or
slow-moving prey, on the other hand, sometimes have to fly long distances to find
food, and thus tend to have shorter, wider wings for slower flight.
4


Aerial insectivores have large tail membranes (uropatagiums) that can be used to
catch insects while flying, wile many other species have reduced or absent tail
membranes.
We’ll talk about how these features differ between the major bat families of Costa
Rica on the following slides.
o Bats of Costa Rica
 Almost half of Costa Rica’s 240 mammal species are bats!
 There are now 111 species of bats in Costa Rica, distributed among 9 families (the
most recent species discovery was just last year; thus, it is not improbable that more
could be discovered in the future; we are still in the early stages of bat research (i.e.
figuring out what species are living where!))
 This represents about 11% of the world’s bat species, while Costa Rica is less than
1% of the world’s landmass.
 About 60 species in the Monteverde area
 This can be compared to the entire U.S., which only has 47 species, among 4
different families (Mormoopidae, Phyllostomidae, Vespertillionidae, Molossidae).
o Ecological Roles/ “What are bats good for?”
 What role do bats play in the ecosystem?
 Insectivores are important for controlling populations. In the tropics, the fruit and
nectar feeders are extremely important in pollination and seed dispersal, and all
bats are a natural source of fertilization. Of course, they also provide food for other
animals. We’ll talk about each of these in turn.
o Insect Control
o The insectivores are important for insect population control, with some colonies
eating hundreds of tons of insects every night.
o Specifically, they help control mosquitos, which carry the vast majority of insectborne diseases (e.g. malaria). Some vesper bats can eat up to 600 mosquitos in one
hour!
o They can also eat insects that are agricultural pests, acting as a sort of natural (and
free!) pesticide. Some studies have estimated a $1 million savings in farmer costs for
every 10,000 acres of crops due to this ecosystem service.
o Pollination
 Other bats, namely nectar-feeders, help pollinate flowers, such as that of the
Mucuna liana.
 Bat-pollinated flowers, and their leaves, tend to have certain adaptations:
o White or yellow (to be more easily seen at night)
o Stronger odors at nighttime (bats have a good sense of smell!):
 This pale-colored calabash flower emits an odor of “sweaty cheese”!
o Waxy surfaces to reflect echolocation calls
o Ideal shapes to reflect echolocation calls :
5

One study recently found that the Mucuna leaf’s dish-shape is shaped in a way that
reflects echolocation calls back strongly and from multiple angles, reducing the bat’s
search time by half compared to a flat leaf.
 Photo: Glossophaga commissarisi feeding on a Mucuna liana
o Seed dispersal
 Seeds are separated from fruit pulp as they pass through gut; after, some are less
vulnerable to fungus; some species (Cercropia) have higher germination rates.
 In the cloud forest (here), they disperse the seeds of Cercropia, Solanum, and Piper
trees, each of which are pioneer species, extremely important in the process of
forest regeneration (i.e., these are some of the first plants to grow in areas that have
been cut, or in forest gaps).
 One fruit bat can eat/ poop 60,000 seeds in a night!
 Photos: Carollia perspicillata feeding on a Piper fruit;
 Carollia perspicillata feeding on a Cercropia fruit
o Fertilization
 Additionally, bat feces, called guano, are very rich in nitrogen and other nutrients,
and thus naturally fertilize vegetation in forests.
 It can also be commercially mined and sold as garden or farm fertilizer.
o Food source
 Do you know what eats bats? Bat falcons (pictured), owls, hawks, snakes, other
mammals such as weasels (pictured here: the Tayra).
o Bat Families
 Today we’ll be talking about 6 of the 16 Microchiropteran families, as well as 5
subfamilies, all of which are found in Costa Rica.
o Family Vespertillionidae
 Family Vespertillionidae, also called the common bats, evening bats, or mouse-eared
bats, is the largest and most widespread bat family in the world, containing over 300
species.
 Most are insectivores, and thus have a large tail membrane. They use echolocation
to find their insect prey, but do not have nose-leafs to aid in the hunt; to
compensate, most have relatively large ears.
 Vesper bats are abundant in Costa Rica and elsewhere, and can be found roosting in
hollow trees, caves, or buildings.
o Family Mormoopidae
 The mustached bats are also called “leaf-chinned” bats due to their thick lips with
extra skin folds. With long, narrow wings, they are fast, agile fliers. They also have a
wide tail membrane, which is suitable for catching insects.
 The mustached bats usually roost in large colonies in caves, producing enough
guano to commercially mine.
6
o Family Thyropteridae
 There are only 4 species in Family Thyropteridae, which are called the disk-winged
or sucker-footed bats. We have 2 in Costa Rica. These furry bats are aerial
insectivores, and thus have long tails and tail membranes.
 These bats are unique in that they are 4 of only 6 bat species in the world that roost
upright! (The other two are endemic to Madagascar, in Family Myzopodidae) To do
so, they use structures on their thumbs and heels that are sometimes called
“suction cups.” This adaptation allows them to cling to the smooth, coiled leaves of
bananas and Heliconia, which is where they generally roost alone or in small groups.
 One study in Costa Rica found that the unfurling leaves also serve to funnel bat callsmaking them up to 10 decibels louder- to the roosting bats, thus helping flying bats
find their roost-mates (once the roosting bats hear their family call, they call back to
make location known).
o Family Molossidae
o Family Molossidae, also called the free-tailed bats or the mastiff bats, are a
widespread family - 100 spp (found on every continent except Antarctica)
o They have a robust body with long, narrow wings that give them fast, agile flight to
catch insects on the wing.
o They have a “free” tail that extends out beyond the tail membrane, which helps them
fine tune their flight maneuvers, and they actually include the fastest-flying batsone was recorded at 43 km/hr, but “this is probably an underestimate”!
o Family Noctilionidae
 Family Noctilionidae is a small family, with only 2 species (Greater and Lesser
Bulldog bats), both found in Costa Rica (neither found in San Luis). They are also
known as the fishing bats or the bulldog bats.
 Indeed, these large bats eat fish! They also consume lots of insects and other small
organisms (e.g. crabs, scorpions, shrimp), in ponds and rivers.
 They can detect the water ripples made by fish swimming near the surface, after
which they swoop above the water and use their massive feet and claws to grab
the fish. (since echolocation calls bounce off water)
 They also have cheek pouches that can be used for storing food (for later, after
they’re finished hunting, or to bring back to the pups).
 The bulldog bats supposedly retain a strong, fishy odor.
o Family Phyllostomidae
 Family Phyllostomidae, or the American leaf-nosed bats, is a tropical family found
in Central and South America (from Mexico to Argentina)
 Phyllostomidae is the largest family in Costa Rica, and the most ecologically varied
family of all bats, thus it is divided into 5 subfamilies, each of which is represented
here in San Luis. Despite their variety of roosting and feeding habits, almost all of
the Phyllostomidae have structures called nose leafs (all except the vampires and
Centurio senex).
7

What is the nose-leaf? What do you think it’s used for? It is thought that the nose
leaf helps direct and “broadcast” vocalizations during echolocation. The size and
form of these differ substantially among species.
o Subfamily Phyllostominae
 Subfamily Phyllostominae includes the gleaning and carnivorous bats. Food includes
small arthropods, birds, and small mammals, which they glean from the ground,
vegetation, or trees. (“gleaning” is a type of food searching strategy wherein prey
are snatched up from other surfaces, rather than caught in the air like aerial
insectivores)
 Fly slowly and sometimes long distances, searching for prey. They are generally
found in primary forest.
 Includes the largest bat in the Americas, the Vampyrum spectrum or “false vampire
bat”, with a wingspan of about 1 meter (found here!). In Guanacaste, one was found
to have eaten 18 species of birds! also can eat lizards, rodents, and other bats.
o Subfamily Glossophaginae
 Subfamily Glossophaginae are the pollen and nectar feeding bats. These rather small
bats have special adaptations for feeding on flowers, including a long, narrow
snout, a long tongue, and the ability to hover at the flower. The tail membrane is
usually lacking (since they are not catching insects),
 They behave like hummingbirds, and are important pollinators in tropical forests.
One study in Ecuador found that bats carried ten times as many pollen grains as
hummingbirds! (Probably due to their furry heads; doesn’t necessarily mean they’re
more efficient)
o Subfamily Carollinae
 Subfamily Carollinae are known as either the short-tailed or the piper-eating bats,
because they specialize on the fruits of Piper plants (a common tropical family that
is important in forest regeneration). They basically eat a piper fruit like an ear of
corn, nibbling on the seeds. They then defecate as they fly, thus dispersing the seeds
throughout the forest.
 They are distinguished by a U-shaped row of small warts around a large central
wart on the chin (compared to the gleaners, with a V-shaped pad); these are thought
to be used as a sensory mechanism.
 There are only four species in Costa Rica, but it is a fairly abundant family; many of
the bats that you see flying around campus at night are likely Carollia.
o Subfamily Stenodermatinae
 Subfamily Stenodermatinae are the fruit-eating bats, which are abundant in Costa
Rica and are incredibly important for seed dispersal in tropical forests.
 Fruit diets vary, but may include figs, guitite, Solanum, Cercropia, bananas, guavas,
palm fruits, etc.
 Because they are not eating insects, they usually lack a tail membrane (and tail), and
they have large eyes that aid in finding fruit. Stenodermatinae have blunt faces and
8




medium-sized nose-leafs, and many have facial or back stripes, which are thought to
aid in camouflage.
You can also notice that they have strong shoulder muscles, which can help them
carry heavy fruits.
This family also includes the tent-making bats. There are actually 15 different
species of tropical, New World bats that manipulate their surroundings to construct
tent-like living structures.
For example, the Honduran white bat (Ectophylla alba) found in Costa Rican
lowlands (not here), uses Heliconia leaves to construct a tent by cutting the side
veins of the leaf, causing the sides to fold down, providing protection from winds
and rain. Generally 6-8 roost together in a leaf. Further, they have white fur, which
reflects light from the leaves, thus giving them a greenish coloration that provides
further camouflage.
The tent-making bat (Uroderma bilobatum) also folds large leaves- usually banana
or palms- into a V-shaped tent. One tent may last up to 60 days before dying and
falling off the plant, after which they spend a few days constructing a new one.
These roosting groups can range from 2 to 59 individuals!
o Subfamily Desmodontinae
 There are only 3 species of vampire, or blood-feeding, bats, all of which are found in
Costa Rica. One of these, the common vampire bat (Desmodus rotundus) feeds on
mammals, while the other two feed on the blood of birds (the hairy-legged vampire
bat (Diphylla ecaudata) and the white-winged vampire bat (Diaemus youngi)).
 Vampire bats have small ears, a short tail, and a large, flattened nose pad (no nose
leaf). They have fewer teeth than other bats, but much larger and sharper canines
and incisors.
 First, the vampires fly to the general location of the victim animal. They then land
and run on the ground and jump onto the sleeping animal (e.g. cow). Because they
have evolved large thumbs and strong, specialized wing muscles, they can run up to
5 miles per hour! (only bat with this ability!)
 The common vampire bat has specialized infrared-sensitive receptors
(“thermoreceptors”)- three facial pits that allow them to detect small differences in
temperature- which help them find areas where the blood vessels flow close to the
skin of their victim. Thus, they usually feed on either the neck or the flank. (the only
other vertebrate with thermoreception capabilities are boas, pythons, and pit
vipers!)
 They then shave away any fur before they use razor-sharp teeth to slice the skin
without pain, usually without waking the victim. The saliva contains an
anticoagulant, thus preventing the blood from clotting so that it can flow for longer
(in fact, this is so effective that it has been used to develop medication for stroke
victims).
 The vampires lap up the blood (they don’t actually suck it) with grooved tongues.
 Vampires are highly social bats, usually found in large groups (about 50 but up to
1000s), and roosting in either caves or hollow trees. Vampire bats exhibit reciprocal
altruism, or sharing behavior. Each bat needs to drink blood at least every other
9

night, but cannot always find an animal. Thus, individuals will regurgitate and share
blood meals with individuals that didn’t find an animal, a favor that is returned later.
They also participate in social grooming, and are the only bats known to “adopt”
orphaned baby bats! (strong family bonds)
o Unfortunately, “bat populations are declining almost everywhere,” which is largely
due to:
o Threats to Bats
 Habitat loss
Richard K. LeVal: “large scale alteration of bat habitat has already occurred. For example, of
the original dry forest that covered western central America, including Guanacaste, only
2% remains. Most of the original wet forest that covered the Carribean lowlands of CR is
now gone. And most of the premontane and montane habitats on the Pacific side are also
gone. Agricultural habitats sometimes support a large number of bats, but of few species.”
Some species are restricted to primary forest.
 Use of pesticides and other toxic chemicals
Especially on large multinational farms in the country (e.g. pineapple and banana).
 Climate change
Warmer temps- as is the case with other species, some bat species are moving up in
elevation; some bats are confined to highest altitude, meaning that they could be “squeezed
off the mountain.”
 Deaths from windmills
Windmills in North America may kill about 700,000 bats annually; CR is expanding wind
energy, meaning this could become more of an issue.
 Misconceptions and farmer-conflicts, and resulting deaths
“A common belief is that all bats are vampires…efforts to control vampire bats usually lead
to the undesirable and unnecessary death of beneficial bats.”
Understandably, many farmers are in conflict with vampire bats that are harming their
livestock, which has resulted both in their deaths as well as the deaths of other bats, if
misidentified.
 Slow recovery in cases of population decline
Because bats have such slow reproduction, it is difficult for populations to rebound after
suffering declines.
o White Nose Syndrome
 White nose syndrome is a disease that is devastating populations of bats across
North America.
 It has killed more than 5.7 million bats, of 7 different species, since it was discovered
in New York state in 2006. Mortality rates are 100% at some sites.
 WNS is so named for a white fungus (Pseudogymnoascus destructans) that grows on
the noses, ears, and wings of infected bats. It is thought that it causes hibernating
bats to wake up and emerge from their hibernation prematurely. They then use up
their winter fat reserves and either freeze or starve to death.
10



WNS has been spreading from the east across the U.S. (see map). It is thought that
bat-to-bat transmission is the primary mechanism, though humans may also be
inadvertently contributing to the spread of fungal spores between sites (and many
caves in the U.S. have been closed for this reason).
Will WNS affect Costa Rica’s bats? From Bat Conservation International: “The
ecological and geographical limits of White-nose Syndrome are not yet understood.”
Some evidence suggests that bats with short hibernations will be less affected, and it
seems that bats without hibernation patterns are unaffected (because of warm
temps, many tropical bats fall into this category.)
Costa Rica, however, has its own conservation concerns.
o Conservation Measures: So, what can you do to help?
 Bat homes
o Thin, narrow boxes can provide bats a place to roost
 Bat night gardens
o Planting bat-pollinated flowers may draw in more nectar-feeders
 Pesticide reduction
o Buying organic; using less on your own garden
 Reforestation
 Habitat management
o Managing forests for bat roost preferences, such as old hollow trees
 Education and outreach
o Like this! Get educated and share the knowledge with others. Arturo has
down outreach programs in the area to teach identification skills to farmers
to eliminate deaths from misidentification. Also, hands-on activities with
kids, school groups, tourists, can increase awareness and interest in these
fascinating creatures.
o For more information, check out the Bat Jungle in Monteverde (run by Costa Rican bat
expert Richard LeVal), or read more from these sources: links.
OTHER NOTES:
• Bats are warm-blooded like all mammals (meaning they internally maintain their
body temp), yet have the ability to enter a torpor state each night, in which their
metabolism slows and their body temperature drops, allowing them to conserve
energy (similar to hummingbirds!).
• Most bats in temperate areas either hibernate through the winter (oftentimes in
caves), or migrate to warmer locations.
• What eats bats? Hawks, owls, other bats; sometimes snakes or predatory mammals
(e.g. weasels) can climb up and eat roosting bats
• Why do bats roost upside down? Unlike birds, bats cannot take flight from the
ground (this is because their wings cannot produce enough lift, and their hind legs
are not strong enough to run up to a takeoff speed; rather, they have to climb up a
11
•
•
•
•
tree using their front claws, then drop into flight). Thus, they are ready to fly from
the roosting position. Also, there is little competition for their small roosting
locations, and gives refuge from predators.
How do they hang upside down? When they relax, their talons naturally close,
thus gravity allows them to hang without having to exert energy.
Do bats carry diseases? In fact, very few diseases can be contracted from bats. Less
than 1% carry rabies (mostly vampires), and it is rare that humans contract it.
Can bats smell? Yes, they have a good sense of smell. Some use it to find fruit or
flowers, while many use it to identify family members.
Echolocation: One transmitter and two receivers (the ears)>> the echoes arrive to
the two ears at different times and different loudness>>these differences are used to
perceive distance and direction.
Created by Emily Deitchler, UGA Resident Naturalist, April 2014
12