Story Written By: Joel Southern

Come early June in Bracken Cave, 1,000 bat pups are born every minute, cleaned by their mothers and smell their way to the breast for their first meal.

The bat pup must wait four to five weeks before gathering the courage to leap from his cave wall and reach for the oblong hole in the cave's ceiling where his mother disappears nightly and returns with food.

When a month old, the pup's yearning to fly mounts with his growing taste for the juicy insects his mom drops down his throat. And then she is gone again.

Weighing in at only a half ounce, the mother must eat nearly three quarters of her body weight each night to maintain the energy needed to feed herself and her pup.

The nursing cave is safe and warm, comfortable at about 100 degrees because of the decaying feces and dripping ammonia-saturated urine. It lies still, comforted by the steady but raucous melee of clicking sounds vibrating through its nervous system.

The pup does not know it, but he is able to stay attached to the rock face by a unique tendon locking mechanism on his foot.

As soon as the light hole on the ceiling begins to transition into darkness, scouting bats leap from their upside down perches and begin an energetic corkscrew flight pattern directly into the light hole to test the safety of the night sky.

The young bat pup watches and listens while packed into the impenetrable square foot of wall space that he shares with 500 roost mates. Envision this square foot of clattering bat pups, then step back to view 425 by 50 feet of cave wall chock full of pups, their mothers congregating separately close by.

Then, one at a time, millions of free-tailed bats bound upwards wing-to-wing like jet fighters determined to pierce the eye of a needle above them.

University of Tennessee biology professor Dr. Gary McCracken understands the urge and quest of the free-tailed bats. For 25 years, he has researched the populations, ecology, and genetics of this fellow mammal.

The bats, as McCracken explains it, are the good guys.

Consider their appetites. During June when the pups are salivating for their first meal caught on the fly, billions of earworm and armyworm moths hatch in the cornfields nearby. In south-central Texas alone, free-tailed bats eat a whopping two million pounds of insects a night.

Meanwhile, the U.S. Department of Agriculture and farmers spend hundreds of millions of dollars yearly on pesticides trying to stamp out these moths.

Besides the use of pesticides, reasons for bat decline include:

• habitat destruction
• direct killing
• disturbance of hibernation (arousal causes bats to use their winter fat needed to support them until insects are again available in spring; can cause bat starvation)
  
• vandalism
  
• maternity colonies (disturbance causes many bats to be dropped to their deaths or abandoned by panicked parents)
  

Pest infestations ruin an estimated 25 percent of crops nationally each year. The potential of bats to ameliorate this crisis seems overlooked.

But not by Gary McCracken.

McCracken and his team's research energies are focused now, in part, on quantifying the economic benefits of the free-tailed bat.

When farmers sit down at the end of the day, they would be wise to look to the evening sky and give thanks to the efficient flying and eating machines. Bats offset billions of dollars of crops lost annually to invading pests-bat's favorite food.

To better examine the lifecycle of bats, McCracken adopts audio and visual technologies, or invents methods when no off-the-shelf solution exists.

He was among the first scientists to use DNA analysis of feces to document feeding patterns of bats. Frustrated that he couldn't "hear" bats at high altitudes, he wrote a grant that allowed him to charter hot-air balloons with sophisticated sonar equipment into mile-high bat cafeterias.

Bats use high frequency echolocation outside the range of human hearing to navigate the sky and to locate their prey. They use a similar vocal call to find their babies when they return with food.

Generations of bat researchers assumed that nursing mothers chose pups at random. But in an article published in Science in the mid 1980s, McCracken presents findings that demonstrate that 83 percent of mothers successfully locate their own pups for feeding through a mixture of spatial memory, vocal cues between mother and pup and finally, as they close in on their pup, by smell.

Meanwhile, back in Bracken Cave, the month-old bat pup risks everything by unlocking his foot tendon from the cave wall, testing his fragile new wings, and erupting through the small opening above into twilight's secrets, new smells, and biologically driven impulses.

"They are clearly unusual animals," said McCracken. "People fear what they do not know or understand. The best way to counter this fear is education."