Animal Science

The October air is crisp and leaves are falling from the trees in parts of the Northern hemisphere. Bats and black cats are animals we think about when Halloween rolls around each year. Of these two mainstays, one is considered a creepy creature – at least to most of society. The other animal is part of superstition and folklore. In Part 1 of this Halloween series, we'll examine bats– their similarities to humans and how they're ecologically helpful. In Part 2, we'll cross paths with black cats, studying their genetics and then moving on to superstition.

Bat Characteristics

On Halloween night, some people worry about being bitten by bats – probably because of the association between bats and vampires. But during the rest of the year, we might think about the ways bats help us out. For over 50 million years, bats have been around in some form or another. They are the only true flying mammal. Others, like the flying squirrel, can glide (but not fly) through the air.

Beneath their wings, bats have bone structures similar to those of many other mammals, including humans. For example, bats have wrists, metacarpals, and phalanges (fingers). Perhaps this is where part of the folklore about human transformation comes in? Another reason may be that bats give birth to and nurse dependent young – just like humans. Because of these characteristics, Carolus Linnaeus even put humans and bats into the same taxonomic group at first!

More than Alter-Egos for Vampires

The United States has 47 different types of bats. There are about 1,100 species worldwide, a figure that represents 20% of all mammals. In the U.S., bats are classified into four families – ghost-faced, leaf-nosed, vesper, and free-tailed.

So what are bats good for? Most people know that these animals eat bugs. In fact, about 70% of bats are insectivores. The rest are mainly frugivores, or fruit-eating bats. By eating fruit, bats help the planet's ecology by pollinating flowers and spreading seeds. In fact, some tropical plants wouldn't exist without the help of bats.

Echolocation

Another reason some people find bats so frightening is that these winged animals only come out at night. Fear of the unknown and anxiety about what we can't see clearly is a big factor. (Still, some people consider bats to be "cute".) Unlike some other animals, bats don't need to see their prey to eat. Instead, they use echolocation to find it. Let's look at hunting for insects as an example.

In order to use echolocation, a bat emits a high-pitched sound that travels through the air and bounces off something – hopefully an insect. The bat listens for the return sound – the echo. If the echo sounds like it bounced off a bug, the bat flies toward that area and snaps up its dinner.

Echolocation is so sophisticated that it not only tells a bat where an insect is, it can also help it determine how big the bug is and what direction it's moving! This is because smaller objects reflect smaller portions of the sound wave produced. For this reason, it's pretty unlikely that a bat will come after you. Lucky for you, a human reflects the sound in way that a bat knows you're too big to eat!

Editor's Note: Check back next week for Part 2 on the genetics of black cats and their superstitious role in Halloween.

Resources:

http://www.batcon.org/

http://en.wikipedia.org/wiki/Bat

http://animals.howstuffworks.com/mammals/bat2.htm