Posts Tagged ‘Bats’

Throwback: Bat Sniffer

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Monday, December 17th, 2012
Mexican Free-tailed Bat

Mexican Free-tailed Bat © NatureShare

Originally post December 2, 2009 by Jungle Pete

I like a faint smell of skunk, a gentle waft of monkey musk and even an odiferous breeze of bat. Don’t get me wrong, I like traditionally pleasant scents too. Orange blossom. Honeycomb. Fresh mown grass. But when I smell the distinct pungent perfume of the chiropterans I can’t help but get all aflutter.

Bats belong to the Order Chiroptera and number well over 1000 species. Considering that there are roughly 4000+ known species of mammals in the world, bats account for at least one quarter of them. Florida is home to 13 species of flying mammalians yet I was starting to think they had all disappeared. Since 2007, I had seen only one bat. One. But on a warm fall October evening, that would change.

The bridge over Judd Creek in Fort Myers Florida harbors a natural wonder. The underside is full of bats. The double lane concrete structure bridges a narrow gap on the mangrove-lined tidal creek and every evening at dusk, motorists whizz by unaware of the 1000+ bats that emerge for a night of insectivorous snacking.

To witness this spectacle, we kayaked to the bridge before dusk and like clockwork, the first of the bats began to gracefully dive from their concrete roost as the light faded. The expansion joints on the belly of the bridge are spaced perfectly for the two species of bats that roost here. In fact Mexican Free-tailed Bats (Tadarida brasiliensis) roost exclusively in manmade structures in Florida. On the other hand the Evening Bat (Nycticeius humeralis) is more often found roosting under loose bark or in dead trees but they have been known to roost in the bridge as well.

Normally it would be tough to identify one species of bat from another in flight but Mexican Free-tails are unique. They have brown to grey fur and a twelve-inch wingspan but most notably they have a tail that extends out beyond the uropatagium, a membrane that typically connects the hind legs and boney tail.

As the bats plunge and ascend, swirl and dive again, the six foot gap between bridge and creek fills with hundreds of elegant, swarming bats and the evening breeze bellows a fantastic scent of bat musk. Often confused for the smell of guano or bat droppings, the pheromone helps bats identify one another. The swirling mass begins to separate and one by one the bats zip off into the night.

I gently float with a subtle current, watching a wisp of a blackened wind trail off into the darkness leaving me in the lightless night with an ephemeral aroma of bat.

All We Have To Fear…

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Monday, October 29th, 2012

All We Have To Fear © Jungle Pete

All We Have To Fear… by Jungle Pete Corradino 

Arachnids with web spinning architectural prowess
Long-legged daddies with eight legs more or less
Brown furred mammalians with leathery wings
These are a few of my favorite things

Snakes striped with colors that will kill-a-fella
Turtles accused of passing salmonella
Poisonous ivy that desperately clings
These are a few of my favorite things

Aquatic finned creatures with razor sharp gnashers
Thundering, bumbling, honeycomb crashers
Well armored grubbers with nine banded rings
These are a few of my favorite things

When people fear them
When they kill them
This makes me mad
Please would you respect my favorite things
And then I don’t feel so bad

Bats and Moths: An Arms Race

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Thursday, July 12th, 2012

Bats and Moths: An Arms Race by Kent McFarland

For nearly 65 million years bats and moths have been locked in battle. Bats developed ultrasonic sound to track moth prey at night. Moths countered with ears capable of hearing the bats. The bats responded by changing their frequencies. Tiger moths, responded with the ability to actually create their own ultrasonic sound. They are locked in a coevolutionary predator verses prey race for survival.

Many moths in the Noctuidae family have tiny organs in their ears that can hear the echolocation calls of bats. Weak calls, indicating the bat may be some distance away, causes the moth to flee from detection. A strong detection of an approaching bat instantly produces erratic flight. The moth’s wing muscles literally go into spasms causing their flight to be an unpredictable loop, twist or twirl. A last ditch effort by the moth is the complete folding of wings causing a free-fall. The moth responds to the detection of bat calls in a mere 40 to 100 milliseconds. Be quick or be eaten.

Bats and Moths

The foul tasting Virgin Tiger Moth (Grammia virgo) warns daytime predators such as birds with its bright color and nocturnal predators like bats by emitting sound. © Kent McFarland

The Tiger Moth (Bertholdia trigona) in the southwestern United States has actually developed the ability to jam a bat’s echolocations. It has an organ on its body called a tymbal and it works like the popper in the board game “Trouble”. Push it down and it snaps back with a clicking noise. Biologists have measured up to 450 clicks in just one-tenth of one second coming from this organ. When a bat locks onto its target, the moth begins to rapidly click its tymbal. The bat becomes confused, slows down and misses the moth. What’s next for the bats?

What’s the Buzz on Pollinators: Bats

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Thursday, June 21st, 2012

Bat Facts:

Mexican Long-tongued Bat © Charles W. Melton

The Lesser Long-nosed and Mexican Long-tongued bats migrate 1,000 miles north every year from Mexico to Arizona, New Mexico, and Texas. Bats are vital pollinators in the tropical and desert climates and flock to large, pale flowers with fragrant, fermenting and fruit-like scents. Bats pollinate agave plants, saguaro plants and fruit trees, including mango, banana and guava.

Lesser Long-nosed Bat © Merlin D. Tuttle/Bat Conservation Int’l

More Bat Facts:
1.) Much like a human mother’s instinct to take in orphans as her own, female bats do the same.

2.) In West Africa bat droppings are highly valued. The excrement is used as fertilizer and adds nitrogen to soil.

3.) Bats can digest mangoes, bananas, and berries in 20 minutes.

4.) The saliva from Vampire Bats, which acts a blood thinner enabling the bat to drink the blood of a living animal unhindered by naturally clotting, has recently been used to treat heart conditions and strokes.

5.) A colony of bats may consume 400,000 pounds of insects in a single night.

6.) The Bumblebee Bat of Thailand is the world’s smallest mammal, weighing less than a penny.

7.) Although they have poor eyesight, bats have immaculate echolocation abilities. The Fishing Bat can sense a minnow with a fin as fine as a human hair protruding two millimeters above the waters surface.

8.) 200 tons of insects are eaten every night by the 20 million Mexican Free-tailed Bats who live in Bracken Cave, Texas.

Giant Saguaro Bloom by Charlie Rattigan

Giant Saguaro Bloom by Charlie Rattigan

Bats in Trouble

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Tuesday, November 30th, 2010

Big Brown Bat

We don’t know as much about bats as we should, and often what we do “know” is wrong. Professor Craig Willis of the University of Winnipeg is trying to change that. But he’s up against a mountain of opposition. Pop culture is his biggest enemy.
That’s probably why he objects to being called “The Bat Man”. Silly, teenage myths don’t help. Promoting bats as bloodthirsty, hair-grabbing, vampire-friendly, rabies-ridden monsters is just wrong.
Because of our boreal forests and limestone caves, Manitoba is a good place for bats. Of our six species, three are migratory (Hoary, Eastern Red, and Silver-haired Bats) and three are hibernating (Little Brown, Big Brown and Northern Bats). Both groups are in serious trouble but for different reasons.
Wind farms are killing migratory bats; those giant wind turbines cropping up everywhere are more of a threat to bats than to birds. Prof. Willis has discovered that bats that travel through the prairies, especially in the fall, are attracted to tall structures like wind turbines (also radio towers) during migration. Hundreds of thousands of dead bats have been discovered near them over the past ten years or so. With blades that spin at fourteen times per minute (or 210 kilometers – 140 miles — per hour at the tips) bat deaths are caused not just by collisions but from decompression of the flying mammals’ lungs as well.
Hibernating, non-migratory bats are dying at alarming rates in Quebec, Ontario, and the northeastern US. In the past four years over one million bats have died from White Nose Syndrome (WNS), a fungus that affects bats’ ability to survive hibernation. This is perhaps the fastest decline of a wildlife species ever.
WNS has not yet reached Manitoba. But it’s only a matter of time. Although only a small percentage (6%) of our bats leave Manitoba, the ones that do can travel over three hundred kilometers (180 miles). Contact with diseased bats is almost inevitable.
Because bats have complex social systems and can survive up to 35 years in the wild, they have low reproductive rates. This makes any population disturbance a concern. Bats are slow to recover.
Bats do not eat mosquitoes, but they can consume as many as 600 bugs per hour (mainly moths) through their uncanny echo-location. They probably save the North American farm economy billions per year.
Prof. Willis indicates that Dr. Scholl’s Foot Powder could save hibernating bats from WNS. It’s probably not economical to send cadres of spelunkers into caves to powder bats’ noses.

White Nose Syndrome

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Monday, November 2nd, 2009

Bats across the Northeast continue to suffer cataclysmic population losses as White Nose Syndrome rages on. How will bats in other regions of the country be affected as WNS persistently spreads through hibernating bats? Most bats in the southeast do not hibernate which could prevent WNS from affecting those species.

White-nose Syndrome: Something is Killing the Bats

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Tuesday, October 20th, 2009

For bats in the Northeast, fall means swarming time. Bats arrive at cave openings by the hundreds and thousands in preparation for hibernation. But this year, this bat tradition is missing from some caves and old mine shafts. White-nose Syndrome (WNS) has taken a serious toll.

In February 2006 near Albany, N.Y., a caver photographed hibernating bats with an unusual white material on their muzzles. He noticed several dead bats. The following winter more bats were found behaving erratically, others with white noses, and a few hundred dead bats were found in several caves. New York Department of Environmental Conservation biologists documented white-nose syndrome in January 2007.

Hundreds of thousands of hibernating bats have died since. Biologists with state and federal agencies and organizations across the country are still trying to find the answer to this deadly mystery. Bats have been found sick and dying in unprecedented numbers in and around caves and mines from Vermont to Virginia. In some hibernacula, 90 to 100 percent of the bats are dying.

While they are in the hibernacula, affected bats often have white fungus on their muzzles and other parts of their bodies. They may have low body fat. These bats often move to cold parts of the hibernacula, fly during the day and during cold winter weather when the insects they feed upon are not available, and exhibit other strange behavior. During late winter and early spring this year I was contacted by many people wondering why they had seen bats flying during the day with snow still on the ground.

Recently, biologists from the Vermont Fish and Game Department and the US Fish and Wildlife Service conducted their annual fall survey of the Elizabeth Mine in Strafford, VT. In normal years they capture around 900 bats during the survey. Last year they found only 300 bats. This year one juvenile male bat was captured on the first night and just one more two nights later.

U.S. Fish & Wildlife Service

Despite the continuing search to find the source of this condition by numerous laboratories and state and federal biologists, the cause of the bat deaths remains unknown. Recent identification of a cold-loving fungus could be a step toward an answer. Although biologists are not sure this is the killer, it is the leading candidate. The current hunch is that perhaps it was introduced accidentally from Europe, but that is just speculation at this point.

This year biologists are conducting an experiment to help understand WNS transmission. Healthy bats from Wisconsin are being sent to Vermont at the end of October. Two sites in VT now have bats excluded from them. The healthy Wisconsin bats will be placed in the mine shafts to hibernate. If these bats contact WNS, the biologists will know it is from the hibernacula and they can then come up with a way to eradicate the fungus from the cave.

One thing is certain, bat populations are in serious trouble and biologists are scrambling to find the answers before it is too late.