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Bats on Blow?

February 11, 2008

Throughout northeastern North America, scientists are finding dead bats with a white substance around their nostrils. In a handful of caves throughout New York and Vermont, researchers are trying to figure out just what is killing these bats, and how it is jumping from cave to cave. In upstate New York, 90% of the bats in one cave succumbed to this mystery illness over the past 2 years. Is this a bat pendemic? If researchers don’t figure out exactly how the bats are dying, how the disease is transmitted and most importantly, how to contain it, then it could be.

The powdery looking substance around their nostrils is the white Fusarium mold–ruling out the obvious theory of an out of control cocaine addiction in the bat community. But while scientists have identified the mold, they don’t know what role–if any–it plays in the deaths.

Theories abound. The “white-nose syndrome” could be linked to increased pesticide use in agriculture. The mold could be a symptom of a new pathogen (any disease-causing agent like a virus, bacterium or some other microorganism) in the bats’ environment. Or maybe the bats are more susceptible to existing disesases because of poor nutrition.  

Right now the die-offs are limited to around 10 sites in New York and one in Vermont, but white-nose syndrome has already spread to four different species of bats, including the endangered Indiana bat. Little brown bats (Myotis lucifugus) make up the largest percentage of the dieoffs, but that may be because they are the most common bat in North America. Little brown bats are found in almost ever state and every province in North America.

With close to a thousand bat species worldwide, bats represent a fifth of all mammal species. There are two kinds of bats: microbats and megabats. Like their name suggests, microbats are small. The smallest is the hog-nosed bat in Thailand, a microbat that weighs only two grams, or seven hundredths of an ounce. Although some microbats eat fruits and nectar, most microbats are insectivores—they only eat insects. And they do it quickly, eating half their body weight in bugs each night. (Little brown bats can eat 600 mosquitoes an hour.) And they do it blindly. Microbats are nocturnal (they only come out at night) and have such poor eyesight that they must rely on echolocation to find their prey.

Echolocation works much like the sonar used by submarines. The bats send out high frequency sound waves that bounce off insects, trees and anything else in their way. The returning sound waves not only tell the bat that something is there, they also let the bat know the size, shape and density of an object, and how far away it is. But not all bats echolocate. Megabats, less familar cousins of the microbats we know in North America, don’t echolocate (with the exception of one Egyptian species). Some megabats even fly around during the day. 

While microbats are found worldwide, megabats are found only in Asia and Australia. And unlike microbats, megabats are huge. The world’s biggest bat, the gigantic flying fox found in Asia, has a massive 6-foot-wide wingspan. But there’s no need to cross Asia off your list of places to visit. Gigantic flying foxes, like all megabats, only eat fruits and nectar.   

Bats are more important than most people realize. They eat mosquitoes and other nighttime pests, but they also protect our agricultural industry by eating bugs that directly damage crops, like grasshoppers and leafhoppers. And they eat beetles and moths, whose larvae also damage crops. As for those bats that eat fruit and nectar? They are important pollinators, especially for a number of cactus species in the southern US and Mexico.

Bats are already getting hit hard by habitat loss and decreasing prey availability (thanks to pesticides). And while scientists don’t know what’s happening to the white-nosed bats yet, many bat specialists consider this one of the biggest threats to bat-kind that they have ever seen. 

One Comment leave one →
  1. February 11, 2008 2:22 am

    I found your site on google blog search and read a few of your other posts. Keep up the good work. Just added your RSS feed to my feed reader. Look forward to reading more from you.

    Karen Halls

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