Wildlife Disease Association
St. Augustine, Florida
By Merlin Tuttle
The Wildlife Disease Association hosted a panel discussion on vampire bats (Desmodus rotundus), their impact, status, and changing distribution on August 5, 2018. A panel of six speakers from Europe, Mexico, and the U.S. were invited to speak. In the lead-off, tone-setting presentation,
I outlined the global value of bats, with special emphasis on Latin America, then proceeded to discuss my decades of observations on vampire control and the enormous damage done when beneficial species are inadvertently targeted. I favored control limited to the vampires causing problems. However, I emphasized that vampire problems are two-fold. One of course involves feeding on livestock and occasionally humans. The other involves their potential impact in crowding other species out of already declining roosting options. The dramatic expansion of vampire populations due to livestock introduction is likely impacting many other bat species that are essential to healthy ecosystems.
During my early bat surveys in remote rain forests inhabited only by aboriginal Indians, I rarely encountered vampire bats. In fact, I do not recall ever having seen a Yanomamo Indian bitten, despite their habit of sleeping nude in lean-to shelters without mosquito nets. I first encountered significant numbers of vampire bats where Indians under European influence were keeping chickens, pigs, or other livestock. My anecdotal observations indicated that humans first became substantial targets when they began keeping pigs or chickens. Vampires became accustomed to feeding on these, and when they were slaughtered for feasts, the hungry bats turned to humans. Later when ranchers sold livestock, again suddenly reducing the food supply, vampires whose numbers had grown to depend on their herds, turned to people.
Only three species of vampires exist. All live only in Latin America, and only one, the common vampire, poses a significant threat to human interests. More than 350 other species are highly beneficial, keeping insect populations in check, pollinating flowers, and dispersing seeds.