By Grethel Capistrán, Greater Big Bend Coalition Board Member
There are a lot of myths about bats and I have heard so many. For instance, many believe that bats become vampires at midnight, attack people for their blood, all transmit rabies and that guano is extremely dangerous. Lately, bats have suffered a lot of backlash because of the COVID-19 pandemic, but the truth is they are not to blame and furthermore, they play an important ecological role in our ecosystems. (Note – The CDC reports that the origin of COVID-19 from bats is possible, but not proven.)
Bats belong to the order Chiroptera, the second most diverse mammal group, only after rodents. They are the only mammals capable of an active flight, allowing them to occupy a great diversity of ecosystems. Their flying capacity and nocturnal habits have helped them develop a really amazing adaptive evolutionary trait, echolocation, allowing most species to travel and feed in complete darkness.
The Chihuahuan Desert ecoregion is home to more than 130 species of mammals, including some 25 bat species. Insectivorous bats, such as the pallid bat (Antrozous pallidus), Mexican free‑tailed bat (Tadarida brasiliensis) and Townsend’s big-eared bat (Corynorhinus townsendii), help regulate insect populations preventing plagues and insect transmitted diseases.
Mexican free-tailed bats, form colonies of up to 2 million individuals, eating about a ton of insects each night. The guano of Mexican free-tailed bats in caves is considered to be an excellent fertilizer. Additionally, when hunting and foraging they tend to stand on flowers, becoming secondary pollinators.
Nectarivorous species that feed on pollen and nectar, like the Mexican long-tongued bat (Choeronycteris mexicana) and greater long-nosed bat (Leptonycteris nivalis), are responsible for most of the Agave species and columnar cacti pollination, an amazing co-adaptation, but rarely witnessed. Occasionally, insects are also eaten, as well as cactus fruits (helping disperse seeds throughout the desert).
Nevertheless, the Mexican long-tongued bat is listed as “Near Threatened” by the IUCN because of its fragile and threatened habitats. The population is also in decline due to human activities in cave roosts (ecotourism). The greater long-nosed bat is listed as “Endangered” by the IUCN because the population size has dramatically decreased in some sites. Major threats include disturbance of cave roosts, loss of food sources through clearing of land and human exploitation of agaves.
Vampire bats can also be found in the Chihuahuan Desert. The common vampire bat (Desmodus rotundus) is found in the far south and the hairy‑legged vampire bat (Diphylla ecaudata) to the east. Anticoagulant agents in vampire bats´ saliva have been used to treat heart attacks and strokes in humans.
In conclusion, the role that bats play in the Chihuahuan Desert and for our benefit is extraordinary. Do not underestimate or fear them!
WHAT CAN I DO TO PROTECT THEM AND ME?
- When hiking, do not disturb roosting sites (caves, old mining caves) as it could lead to population stress and decline.
- Keep in mind that some species of bats might be protected by federal laws. Stay away from trouble!
- Although not all bats carry rabies, do not attempt to capture them or any wild animals, this will lower the risk of a bite, thus contract diseases. When necessary, only specialists should manipulate them.
- Not all bat droppings contain Histoplasma capsulatum, the fungi responsible for histoplasmosis lung disease. But if you must work with or clean guano, wear protective gear such as gloves and face masks. It is also recommended to spray it with water before its manipulation to avoid dispersing fungus spores through the air.
- If bats have been seen on your property, they are probably a migratory species and will be out soon. However they are most likely return next year. If you can, try to coexist with them. If you do not wish to do so, try and make your house the less inviting possible. Remove any hollow logs or dead trees, constant water sources and insect pests.