I'm Marty Stouffer. Of all mammals, none are less understood or less appreciated than Bats. Perhaps the misconceptions are believed because we rarely come in contact with them.
Contrary to popular opinion, Bats are clean, gentle and intelligent.
Using echolocation to navigate, they consume as many as five hundred insects per hour, including some bothersome mosquitos and many crop pests.
Not only are Bats the most important controllers of night flying insects, they also pollinate and disperse the seeds of valuable fruits, nuts and spices.
They've suffered long enough from a bad public image. It's time to shed some light on our "BENEFICIAL BATS".
TRANSITION TO TITLE / MEXICAN FREE-TAILED BATS
The most famous and most photographed Bats of North America are those which populate the Carlsbad Caverns of Southeastern New Mexico.
Thousands of Mexican Free-tailed Bats emerge from the cave entrance in a dizzying display. As the light fades they stream out over the countryside, our only mammals which truly fly--waves of them travel 75 miles or more to feed on night flying insects--mostly moths.
By late spring, the Bats have arrived at Carlsbad, much to the delight of park visitors. They migrate 800 miles north to reach their summer home in these caves.
TRANSITION TO CAVE
Over 250 million years ago, an inland sea covered this area. Limestone reefs formed in the shallows near the shore. Eventually, the sea disappeared and the land was uplifted into mountains.
Scientists estimate that about 60 million years ago, the cave building process began. Acidic water dissolved the limestone, hollowing out a complex network of caves now protected within the boundaries of Carlsbad Caverns National Park.
About 17,000 years ago, Bats discovered these caves.
A perfectly embalmed Bat, encased in a stalagmite over a hundred years ago, underscores the long relationship of bats and Carlsbad.
SWARMING BATS LEAVING CARLSBAD CAVERNS
Each evening from Spring until Fall, several hundred thousand take flight, rising in columns, then evaporating into the twilight skies. When the Mexican Free-tails return at dawn, they may have eaten 100 per cent of their body weight in insects. That's a half million pounds of bugs.
The visual display is amazing, but imagine what it must have been like earlier in this century when the Carlsbad colony numbered nearly nine million! Today, the caverns shelter less than one half million, largely due to human vandalism of roosting sites.
TRANSITION TO ART
Since ancient times, Bats have been portrayed in a negative manner.
Throughout the centuries, artists portrayed Bats as satanic, supernatural creatures. In fact, Lucifer, himself, regularly appeared wearing Bat wings.
Medieval Christians often characterized early day spiritualists as devil worshippers. And, wouldn't you know, the little devils were decked out in their Bat wings.
Witches engaged the "fearsome" creatures in their mystical rituals. Remember the witches in MacBeth and their evil potion that contained "wool of bat?"
But myths and magic aside, the Bat is a gentle, intelligent creature.
One of our largest Bats is the plain-nosed, Hoary bat. Its heavy dark fur is tipped with white, giving it a frosty or "hoary" appearance.
The peculiar looking Western Mastiff of the southwest is the largest American Bat. Its remarkable ears droop over its face.
The smallest American Bat is the Pipistrelle. Tinier than a Hummingbird, the Pipistrelle weighs less than a nickel.
All of the Free-tailed Bats have short ears which join over the nose giving them a pugnacious expression.
The California Leaf-nose has elf-like, over-sized ears and a tiny, triangular flap of skin that sticks up above the nostrils.
The Yuma Myotis is a plain-nosed Bat usually found near water.
Because no fossils have ever been found of anything other than a fully formed Bat, we can't be sure how they evolved. But we do know that 60 million years ago, Bats were swooping in on their legendary wings.
The Bat wing is a thin, yet resilient membrane which resembles a bird's wing in shape. But that's where the similarity ends.
While a bird's hollow bones support delicate feathers, a Bat's wing is made of a thin meshwork of muscle strips covered by skin.
The bones that support the wing resemble a human hand. A long arm extends out from the body, complete with a wrist. From the wrist, finger bones fan out to form the hand.
A bird's wing bones, by comparison, are much simpler in design.
On the Bat, a tiny, clawed spur or thumb hooks out of the top of the wrist, allowing the bat to both crawl and cling. The finger bones support the wing something like the struts on an airplane.
Not all species of Bats in North America fly into the night skies to seek out "insect" prey. Some have an entirely different mission.
In our Southwest, the endangered Lesser Long-Nosed Bats are key pollinators of the most important plants of the desert. The future of an entire desert ecosystem may rest on these important night flyers, whose specially adapted long tongues and noses allow them to feed on night flowering cacti and agave.
BLOOMING CACTUS FLOWER
On hushed wings the Bats come, hovering over the beautiful blossoms, plunging their long tongues into the flowers and gathering its sweet nectar. Pollen sticks to their furry faces and bodies and, as they travel and feed, they cross pollinate the plants.
Although many birds and insects visit these plants in the daylight hours, the flowers are only reproductively receptive at night. And so the Long-Nosed Bat is the only species which insures the future of these giants of the desert.
The Bats visit the night flowering cacti in groups, hunting out the blossoms of the Saguaro and Organ Pipe among others.
But, where Long-Nosed Bats were once abundant, only a few thousand exist today--too few to successfully pollinate every plant.
If this trend continues, the situation will have far reaching implications. Some kinds of giant cacti could be lost to future generations. And, if they die out, so will the many other species of plants and animals which depend on them for food and shelter.
The potential demise then, of the Long-Nosed Bat, takes on enormous importance. Only by protecting them can we insure the future health of the desert ecosystem. And because they spend the winter in Mexican caves, we need to protect them south of the border as well. In many cases, the key to survival depends on preserving their roost sites from human disturbance and vandalism.
Another species which shares the Long-Nosed Bat's desert home is the Pallid Bat. It's a late night hunter which prefers to catch its prey on the ground.
Everything from Crickets and Grasshoppers to Lizards and Scorpions may be on the Pallid Bat's nightly menu. But, in the case of the Tarantula, the Bat gives this co-hunter of the night a wide berth.
The Pallid Bat is a fairly agile walker. Its shorter, exceptionally strong wings help it to maneuver across the desert floor.
Contrary to common belief, this Bat, and at least some other Bat species, have excellent eyesight, allowing them to discriminate patterns, even in low light levels.
Unlike most Bats that need to swoop down and pick up air speed in order to gain altitude, the Pallid can vault into the air to seek a new hunting location, aided by a flight membrane that makes up 80% of its body mass.
TRANSITION TO DAYLIGHT
Bats may spend over 3/4 of their lives asleep, slowing down their respiration and heart rate as they doze in a trance-like, torpid state. For hanging upside down, they have a blood-flow system that works in reverse to humans. And they have toes and knees which bend the opposite direction from ours.
The Pallid Bat often roosts in rock crevices, or old abandoned buildings. Some Bats have even been reported roosting in a pair of boots left on a porch overnight.
MEXICAN FREE-TAILED BATS
Suitable places to roost and rear their young are a particular problem for the Mexican Free-tailed Bats. Most rely on only a dozen caves in the United States, including Bracken Cave here in Texas.
Over 20 million individual Free-tailed Bats live within the cool confines of Bracken, ranking it as the largest gathering place for mammals in the World. As many as 200 adults per square foot may crowd onto cave ceilings, mostly females which raise their young here.
After a gestation period of about two and one-half months, the pups are born.
At birth, the pink pups are nearly 1/3 the weight of their mothers. Like a human female, the Bat mother nurses her young at her breast.
The pups are born hairless, sightless, and flightless but not clawless. After a short time spent clinging under their mother's wings they hang beside her in the roost.
Each evening the mother Bats leave their babies to hunt. Upon returning in the morning, they not only find their pup from among the seemingly identical millions, but they remember the location of their baby to within a few inches. Both pup and mother recognize each others' voices and the mother can confirm the identity of her offspring by scent.
Less than one-half will survive to adulthood. Most that accidentally fall from the roost, die.
Accumulated bat droppings or guano, as well as the bodies of Bats provide a rich food source for the teeming numbers of insects and other animals that live within the cave ecosystem. As the weeks pass, the young Bats grow quickly assisted only by their mothers. Now a grayish-brown, the young are almost as large as their parents.
A mother Bat may be intolerant of a strange baby and will allow only her offspring to nurse.
Even before sunset the adult Free-tailed Bats begin to fly into the darkening skies. This nightly odyssey will see them consume millions of pounds of insects.
BATS LEAVING CAVE BY THE THOUSANDS
In seemingly chaotic fashion, millions flow out of the cave entrance...a flurry of long, narrow wings...dancing silhouettes, spiraling upward to a height of ten thousand feet. The sound of millions of Bats leaving the cave to us humans is just a deafening roar. But to the Bats, it's a symphony in ultrasonic sound.
But predator can become prey. Frequently, other hunters like Owls and Hawks wait for the nightly Bat emergence.
The same echolocation that allows the Bats to catch fast flying insects on the darkest night, doesn't always allow them to out-maneuver the powerful Hawk.
Enter the quick Kestrel, smallest of our North American Falcons. Broad-siding the Bat, the smaller bird succeeds on its first try.
While hungry Bats continue to pour from the mouth of the cave, the Kestrel makes its meal of the 1/2 ounce, mouse sized Bat. Once again, the Red-tail dives, and once again it snares a Bat. The sheer numbers of Bats greatly increases any predator's chance of success.
As the Free-tailed Bats spread out over the Texas countryside, the same full moon greets the California Leaf-Nosed Bats as they begin their nightly hunt.
CALIFORNIA LEAF-NOSED BAT
Bats which hunt insects have the most highly developed sonar. They can truly "see with sound," locating flying insects by sending out high pitched, ultrasonic pulses. The echoes that bounce back are instantly processed. Strong echoes equal large targets. Small echoes, small targets, like this moth. Once the Bat has locked on, some species of moths have the ability to sense its signal and they immediately drop from the air.
Tiny differences in the echo indicate texture, shape, location, and direction of flight.
CLOSE-UP OF FLYING BAT HUNTING
A cruising Bat emits about 10 per second with up to 200 or more clicks per second when closing in on prey--at frequencies 10 times higher than our range of hearing.
A Cricket on its own search for a meal is shielded from the Bats' probing echoes by the irregular shape of the cactus.
When the Cricket leaves its perch, the Bat has no trouble deciphering its characteristics. The aerial chase only lasts a few seconds. Flying at speeds of 10 to 20 feet per second the Bat hones in on its target, scoops it up with a wingtip and passes it into its mouth. Some Bats catch up to a thousand mosquito-sized insects an hour.
Nearly half of all American Bat species are endangered.
An organization founded in the early 1980's called Bat Conservation International is trying to save our Bats from extermination.
Some species that have been evicted from their traditional roosts in caves, dead trees, and buildings can be lured to man-made substitutes.
Simply constructed Bat boxes with roosting compartments can shelter up to 100 individuals. If placed near a constant supply of water, we can increase our chances to attract these helpful hunters of the night.
Despite what we now know about their importance to a balanced ecosystem, Bats are still one of the most relentlessly persecuted animals on earth. One way we can help insure their survival is to erect Bat boxes like this one in our yards and nature preserves. In return for a place to roost, Bats will earn their keep by eating thousands of insects each night. You can obtain a ready made box through several conservation organizations or you can build one yourself. As you can see, all that's required is an open bottom and some snug compartments. By inviting them into your backyard you'll discover the useful and fascinating habits of our "BENEFICIAL BATS."
I'm Marty Stouffer. Until next time, enjoy our WILD AMERICA.