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Ecology

Bats The Wonderful World of Winged Mammals

Bats exist almost everywhere in the world, except polar areas, and they are more abundant in the tropics. They are the second largest order of mammals, behind rodents, reportedly comprising about 20% of all classified mammal species.

By: Emma Romeu
Photos: Mario Torres Sebastián, René Murrieta, Emmanuel Solís, Cristina MacSwiney, César Guzmán

A number of years ago, an extravagant guest installed himself on my balcony. He slept upside down, walked with his wings, and as a proud adult, did not drink milk. On the contrary, this rare visitor used his radar to find insects or ripe fruit, and also, surely to find his lodgings in my main window at those times when the sun of the Caribbean appeased the vanity of the stars. This guest never wanted to enter my abode, which housed, in addition to me, a yearning Amazonian, a migratory bird, two crickets, and a frog in the cleaning bucket.

I loved that house in East Havana, where for the first time I felt like a hostess. I loved the scent of the sea, the beach flowers planted in cups rescued from wrecks, the messages under the door in my world without telephones, and the living room with so, so much love in all of its corners.

My balcony guest left one day; shortly after, so did I … so far away. And now someone is asking me to write an article about bats, to research and highlight their virtues as friends of plants, scourges of pests, makers of compost, a refined link in the long chain of life.

I am doing my homework, but to be fair, I should start by publishing a new report for scientists: “This rare mammal, with one vowel in its name, comes with a certain risk: bats stir up nostalgia.”

The Spanish word for bat, murciélago, or murciégalo as it once was called, has its roots in Latin, where muris means mouse and caecus means blind, describing the bat as a “blind mouse.” But although bats are mammals just like mice, they belong to another zoological order, Chiroptera, which comes from the Greek cheir, meaning hand, and pteron, meaning wing. In fairness, the approximate 1,300 bat species that exist in the world are better described as “winged arms.”

Bats exist almost everywhere on the planet, except polar areas, and they are more abundant in the tropics. They are the second largest order of mammals, behind rodents, comprising about 20% of all classified mammal species.

Biology traditionally grouped bats into two suborders: Microchiroptera and Megachiroptera. The primarily nocturnal small-eyed Micro, which make use of echolocation, are the most widely distributed in the world.

 

The smallest one lives in Thailand and its common name, bumblebee bat, indicates its size (its scientific name is Craseonycteris thonglongyai). But, of course, not all bats are so tiny. One of the largest species of this suborder is the so-called Linnaeus’ False Vampire Bat (Vampyrum spectrum), with a wingspan that measures about three feet and which feeds on birds, rodents, and other smaller bats, according to the book Microchiropteran Bats: Global Status Survey and Conservation Action Plan, edited by the International Union for Conservation of Nature.

The Mega, on the other hand, is not found in the Americas. These are the so-called flying foxes, some with a wingspan of 6.5 feet. The interesting literature on these enormous bats recognizes that some use echolocation, but most use sight and smell to locate their food (fruits, pollen, nectar, and flowers) in the regions of Asia, Oceania, Australia, and Africa.

It’s not difficult to imagine that the wide distribution of bats may be due to their ability to fly and navigate at night, in addition to their enviable acoustic guidance system, which also helps them locate food.

 

Most bats are insectivores, which is another advantage, since insects are the most abundant animal group on the planet. This means bats never have to go without food. Other bat species are frugivorous, taking advantage of pollen and the nectar of flowers; and there are carnivorous ones too, which generally capture smaller vertebrates.

However, many people still only associate bats with vampires. And since vampire bats can be transmitters of rabies, this adds to their bad reputation. When they show up in livestock areas because of the loss of their natural habitats, it further condemns them to being fought directly by humans with extermination techniques. But the truth is that only three species of bats are known to feed on the blood of wild mammals, birds, and livestock.

Bats depend on echolocation for food, movement, and other aspects of their existence, so studying their sounds helps us to better understand them. Dr. Cristina MacSwiney of the Tropical Research Center at the Universidad Veracruzana in Mexico is a biologist who devotes her research to bats. She is part of a project supported by the National Commission for the Knowledge and Use of Biodiversity of México (CONABIO, for its acronym in Spanish). In this research, species are captured, studied, and released into their natural environments, where the sounds they emit are recorded and sent to a database. MacSwiney describes the project: “With this project, we can have a library of sounds that will help us better determine the diversity of bat species in different habitats. This will provide important information to companies, governmental agencies, universities, and other sectors interested in the evaluation of risks and impacts through the study of bats. The characteristics of the ultrasonic sounds that bats emit will allow species identification without capture.

Numerous species of bats are exceptionally skilled at evading nets, so they are often absent from diversity inventories. Our project also seeks to correct this.”

The mammal identification guide produced by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), published in México in 2015, reports that eighty-four of the approximately 1,300 species of bats are in some type of danger with regards to their conservation. Dr. MacSwiney explains that “many factors threaten the survival of bats, especially deforestation and the fragmentation of their habitats. Although they are capable of flying great distances, there are bat species that cannot cross deforested environments. Since 2006, a disease called white nose syndrome, caused by the fungus Pseudogymnoascus destructans, has killed millions of insectivorous bats in the United States and Canada, and severely threatens the survival of some species in these countries.

Other species suffer the continual vandalism of their places of refuge, such as caves and trees, because people want to get rid of bats due to fear and lack of knowledge of the important role they play in our ecosystems. They act as pest controllers, pollinators, and plant dispersers. Additional species are at risk because they are consumed in some Asian countries and Pacific islands as bushmeat, which has decimated their populations.”

 

Going back to the topic of nostalgia…. This is not the first time that the subject of bats has inspired me. In February 2004, I was lucky that Gilberto Silva Taboada, author of the outstanding scientific work Murciélagos de Cuba (Cuban Bats), reported in National Geographic magazine a new record for the fisherman bat in terms of its longevity.

This species is the largest of the twenty-seven that live in Cuba. In 1969 Silva released 216 bats, tagged with numbered metal bands, at a distance from the cave where they were captured in what today is the Caguanes National Park, in the middle of Cuba. A week later, he found that the bats had returned to the cave. Silva explained what happened years later in the NG article I mentioned: “However, we continued to be surprised when, in April 2003, I returned to visit this colony of Cueva Grande. I observed a tagged bat in each of the three roof cavities. I climbed up and had no doubt when I saw the partially illegible number on the metal ring: a new record of thirty-three years and five months for neotropical bat fauna now exists.”

Paying attention to the conservation of bats is the only way to continue enjoying news like the kind that the biologist Silvio Taboada gave to the world. This is why the abundant and mysterious “winged arms” deserve all the help we can give them for their survival.