Vampire bats may be on their way to Texas

Arnulfo Moreno-Valdez, director of the Natural Museum of
Tamaulipas in Mexico, displays a vampire bat

Warmer winters could allow vampire bats to expand their native range from Mexico to Texas, according to researchers at Texas State University.

One expert said the expansion is a result of climate change. Computer models indicate they could become year-round threat to Texas within 50 years.

“They will not survive in places that go below 50 degrees for a sustained period of time,” said Ivan Castro-Arellano, a biologist and wildlife disease expert in Texas State University's Biology Department.

“If the animals can find a place to roost during the day that keeps them warmer than the 50-degree limit, then they will be able to exploit new areas, especially Texas,” said Castro-Arellano.

Castro-Arellano is one of more than 40 scientists throughout the Texas State University System working through the Institute for the Study of Invasive Species in Huntsville to study and develop strategies to deal with invasive species across the state.

The warming trend in Texas is reflected in the recently updated USDA plant hardiness zone map, which generally revised minimum winter temperatures upwards 5 degrees. This climate shift pushes Texas one step closer to becoming suitable habitat for vampire bats.

Because bats can easily fly hundreds of miles, an immediate concern is that vanguard colonies of vampire bats may already be venturing into South Texas.

Warmer weather could allow vampire bats
 to expand their native range from Mexico
into South Texas.

While native Texas bats are beneficial by eating tons of insects that would otherwise damage crops that make up a large part of the state’s agricultural industry, vampire bats could pose a big threat to livestock.

Vampire bats target cattle and other livestock, approaching the animal on the ground and licking it with anesthetic saliva that also prevents blood from clotting. Then, it bites the victim with razor-sharp teeth and laps up the free-flowing blood.

Since they feed on mammals, they can easily spread rabies and infect herds of domestic livestock. They also tend to target the same victim night after night, and repeated feedings can kill individual animals.

Vampire bats cost ranchers in Mexico millions of dollars each year in losses.

“If the animals get here, that’s a real problem for cattle ranchers,” said Castro-Arellano. “As you can see, there are conservation and economic implications for these species that can come into Texas in the future”.

The key, Castro-Arellano said, is to identify such potential roosts before any vampire bats arrive and effectively monitor them.

Castro-Arellano plans to explore probable sites where vampire bats might settle and place remote thermometers in those locations to record temperatures throughout the winter.

If local climates show stable temperatures suitable for vampire bats over a series of years, that data would serve as an early warning.

Strategies for dealing with vampire bats have been developed in Mexico, but they’re most effective if they can be implemented before a colony becomes well established.

Castro-Arellano has not begun collecting any data due to absence of funding. He has discussed combining efforts to tackle the problem with Arnulfo Moreno-Valdez, the director of Natural Museum of Tamaulipas and one of the top authorities on vampire bats in eastern Mexico.

Source: KXAN