A CHAT WITH BAT DEFENDER EXTRAORDINARY

If you’ve ever seen a really beautiful photograph of a bat, one that made you feel like petting the creature rather than swatting it, chances are that photo was taken by Dr. Merlín Tuttle, world-renowned expert on the most maligned of mammals. Dr. Tuttle is the founder of Bat Conservation International, located in Austin, Texas. As Susy and I were passing through, we decided to drop in and ask him a few questions of concern to cavers in México.

Our number one question was what we could do to educate country people about bats, which are in constant danger of being dynamited, poisoned or otherwise “exterminated” in Mexico. Dr. Tuttle began by pointing out the large number of useful plants that are pollinated by bats in our area: avocados, bananas, sapodillas (for chicle), figs, mangos, agaves (for tequila) and many, many more. He explained that the flowers of many desert plants are receptive to pollination only during the first few hours after opening. Since they open at night, bats are ideal for doing the job. On top of that, there’s evidence that possibly all large cacti are bat-pollinated. The loss of bats could mean the loss of many desert plants and all the creatures that depend on them.

Merlín Tuttle’s most effective procedure for turning rural folk into bat defenders was discovered during an encounter with an U.S. farmer who, he pointed out, was “not much different from the Mexican variety.” Merlin asked the farmer’s permission to take a look at the bats in a local cave. “Go right ahead,” said the man, “an’ you kin kill the lot of ‘em off for all I care.’

On the floor of the cave, beneath the bat colony, Tuttle discovered a thick layer of countless insect wings. Immediately recognizing them as belonging to the potato bug, he picked up a fistful and walked out of the cave. Nonchalantly, he asked the farmer what “this stuff” might be.

The farmer’s eyes bulged. “Belong to them no-good tatter bugs,” spouted the farmer. “Curious,” said Tuttle, “looks like that’s all those bats eat!” Merlin then gave the farmer his formula for calculating bat consumption of insects. Using very conservative estimates, you could say an average bat weights 12 grams (42 oz) and, when nursing, eats at least l00% of body weight per night. Now multiply this by a minimum of 200 bats per square foot of inhabited cave ceiling, and you have the weight of insects eaten nightly. In the case of one Texas cave, that turns out to be over 250,000 pounds of bugs!

When Dr. Tuttle next returned to the farmer’s cave, he was surprised to find e large sign there, warning visitors not to disturb or harm the bats. When asked about this, the farmer replied, “well shucks, how I kalkylate it, every one o’ them bats is worth five bucks t’ me as insecticide!

Naturally, we didn’t forget to ask Merlin for the complete lowdown on how to distinguish vampires -which are considered a definite nuisance in many parts of Mexico - from the much greater number of beneficial bats found in the country.

Our goal was not only to be better informed ourselves, but also to help Jesus Moreno prepare a factual “comic book” on bats, which ZOTZ hopes someday to distribute in remote corners of Mexico.

Vampires, explained Merlin, have no tails or tail membranes nor have they a nose leaf, such as those found on fruit-eating bats.

He then showed us two unusual slides. One, a portrait, shows a smiling vampire sporting two pointy upper front teeth, but not quite in the Dracula tradition, as they are small and both in the center. The other slide shows a vampire “walking” up to its prey, apparently using knobs or pads on its wings as extra “feet.” Since bats in a cave are unlikely to pose for portraits, Merlin’s information on guano will probably be most useful on identifying vampires. If it’s a jet black, gooey liquid like coal tar, you can bet it came from vampire bats.

Guano from insect-eaters breaks up easily and may contain bits and pieces of bugs. Fruit bat guano may have sprouts growing it from all the seeds they drop, and the walls of the cave may even show traces of yellow pollen. Finally, vampire bats never congregate in large numbers, meaning those people who have exterminated huge colonies have undoubtedly done irreparable harm.

From bats, we somehow drifted, to the subject of close calls in caves, upon which Merlin described the following memorable incident. He and a friend found themselves in the lowermost section of a Texas cave.

Suddenly both of them mentioned that they were felling quite tired and having a bit of difficulty breathing. This reminded Merlin of an article he had just happened to read a week earlier.

The article described the symptoms preceding death from breathing carbon dioxide and pointed out that a person encountering such symptoms may have only one more minute left to live.

As soon as the 1ight dawned, Merlin grabbed his friend and headed upward. With great difficulty, the two of them struggled to the cave entrance where they both collapsed, breathing in the fresh air in huge gulps. Only after several hours had passed, were they able to stand up and be on their way. CO2 in caves is produced by the collective breath of a bat colony and can settle in low, non-ventilated areas. There is a definite point where oxygen ends and CO2 begins, meaning that if a group is standing in the right (or is it the wrong?) spot. the short cavers could keel over while the others wouldn’t feel a thing. Though not a poison, carbon dioxide can still finish you off quite effectively¡ In regard to guano, we were also warned to keep our noses open for the smell of ammonia or the rotten-egg odor of sulfur dioxide. If you can detect either one, you are already being poisoned and there’s only one procedure, vamoose¡ Before leaving BCI’s headquarters, we purchased their beautiful slide and cassette show. Bats, Myths and Reality, which we have translated into Spanish for presentation in our area.