TONOSI, Panama — Cattleman Francisco Oliva was on a roundup -- of vampire bats. After a swarm of the blood-slurping creatures divebombed his herd and drank their fill one recent night, he corralled several dozen of them in special contraptions that look like giant badminton nets.
He put each bat in a cage and then brushed a poison called vampirin on their backs before releasing them. Back in the bat roost, the animals would be groomed by as many as 20 other bats, causing their deaths. Or so Oliva hoped.
"We have to look for answers, because this little animal is very stubborn," Oliva said days after the capture as he surveyed his 300-head herd, most of it bearing fang marks and red stains from the nightly bloodletting. Oliva said he would exterminate every single bat if he could.
"You keep the good and get rid of the bad," the rancher said, philosophic but wearied by the attacks, "and these little devils are terrible."
More than 100 miles away, on an island research station in the middle of the Panama Canal, Stefan Klose begged to differ. He not only stuck up for Desmodus rotundus, the scientific name for the most common vampire bat, but described the animals as boons to humanity. Research involving bats led to the development of sonar and anticoagulant drugs that prevent heart attacks, he pointed out, and scientists are just beginning to understand the creatures.
"I certainly defend vampire bats' right to a place in the ecosystem," said Klose, a young German zoologist who does fieldwork at the Barro Colorado tropical scientific center run by the Smithsonian Institution. Man's irrational reaction to vampires, he said, reflects "our primal fear of being someone else's food object."
Few animals inspire the repugnance and fascination of vampire bats, and perhaps nowhere are opinions more divided than in Panama, which has 120 bat species. Bats are found everywhere in the world except Antarctica, but they thrive in the tropical rain forests that cover much of Panama because of a plenitude of animal and plant foods, abundant shelter and a lack of seasons to inhibit regeneration. In a tropical environment's biodiversity, bats "have more niches to exploit," Klose said.
On one side of the debate over the creatures are farmers such as Oliva faced with an escalating plague, and on the other are scientists who use bats and the scientific breakthroughs they have inspired to promote biodiversity.
"Bats have developed a radar system that can distinguish the tiniest insect in the middle of dense bush in the dead of night," said Todd Capson, a Smithsonian staff scientist who tracks the development of technology derived from tropical flora and fauna. "It's inconceivable there isn't something more to learn from that."
But the benefits of bats are a tough sell here. Sabine Spehn, another German researcher who recently did fieldwork in Panama, said by telephone from the German city of Ulm that her efforts to explain "the nice things about bats" to Panamanians, such as insect control and seed and pollen dispersion, came to naught.
"The response I got was always, 'The only good bat is a dead bat,' " Spehn said.
The antagonism of rancher Oliva is understandable. Here in the remote and hilly southwestern corner of Panama, he and other cattlemen wage a constant battle against a variety of livestock nemeses such as coyotes, crocodiles, ticks, worms and tropical diseases. He has been driven to the edge of desperation by the increasing bat attacks.
Vampire bats have always been present in Panama and their attacks have ebbed and flowed. "But now the bad cycles have become more frequent," said Argis Barrios, president of Panama's National Cattlemen's Assn.
Scientists theorize that the increased attacks on livestock are the result of logging that has flushed the bats out of food-rich forests, and to the growth here in Tonosi of cattle herds, a ready-made and usually stationary food supply for the bats. "The problem is a man-made one," Spehn said.
During April alone, Oliva said, he lost 10 calves to anemia caused by successive bat attacks. He and other cattlemen bemoan the scarcity of the bat-catching nets, which are strictly controlled by the federal government to prevent their being used to capture endangered birds.
Catching vampire bats with the nets and poisoning them is legal. But Japan, which donated the net Oliva used, has stipulated that a veterinarian always be present to save "good," or non-vampire, bats caught in the webbing, and there are just three vets in the entire Tonosi Valley region, which is about a quarter the size of Yosemite National Park.
Non-vampire bats make up the overwhelming majority of the 1,100 known bat species. Even the scariest of bats, the giant flying fox of New Guinea, which has a Dracula-like wingspan of more than 5 feet, feeds only on fruit and insects. There are only three blood-sucking, or vampire, bats.