Bat Habits

Most bats are nocturnal. They fly and forage for their food (insects) at night. This means that they need safe places to sleep during the day. Historically, caves have provided the kind of protected shelter in which bats can thrive. Hanging from the ceiling of a cave, bats are out of reach of most of their enemies. Some of the most successful species of bats live in large cave colonies. Some of these colonies have millions of members, even up to 20 million!

Bats do not have good eyesight, in fact they are nearly blind. They use echolocation to locate food and avoid obstacles. They have the ability to create and hear noises that humans cannot hear. The sound waves bounce off of objects and back to the bat, which can then judge the size and distance of the object. These subsonic noises vary in length and pulse frequency, and are unique to the individual. Each bat recognizes its own pulse reflections, or "voice," and uses it to avoid objects and to identify food.

Most bat colonies leave their caves more or less together, in large groups after dark. Before leaving every evening, they fly around inside, preparing for departure. Flying around with thousands of other bats inside a cave creates an insane amount of noise! The bats simply ignore their personal navigation systems until they leave the cave.  If you were to wander into the cave at this time, they would crash into you and the sound would be deafening.. 

When bats are paying attention to their sonar signals, they can navigate without crashing into things. They can identify and capture food while it is moving. The echolocation system is designed to locate very small insects. Most of them are less than a centimeter in diameter. Compared to a bug, a human being is a very large, slow moving sound-reflecting surface. Outside of the cave, the chance of a bat hitting a person is very slim!

There are also bats that fly and hunt for food during the day. They sleep outdoors at night in trees, under bridges and other locations. Unlike nocturnal bats, they have well-developed eyes and poorly developed echolocation.

Diving for Water

Microbats often use echolocation to find water as well as insects. They will swoop down to take a drink without landing.

Ideal bat habitat is within a quarter mile of a natural body of water. Those are usually also good places to hunt flying insects.  This isn't crucial, though, and it's still possible to attract bats even without a lake or pond nearby. 

Bats are known to drink from swimming pools, but that sometimes turns out badly.They normally don't land to drink, instead skimming the surface for quick, mid-flight gulps. Some microbats even naturally hunt frogs and fish. The problem seems to be high walls on some pools, which block bats (and other wildlife) from climbing out.  If you have a large pool, a ramp can help a bat escape that 'hits the wall' and gets stuck.

Grooming & Socializing

When bat species aren’t looking for food or sleeping they are usually grooming and socializing. They are very clean creatures and will spend lots of time grooming themselves so that their fur remains soft.

They can be very caring creatures. In some bat species the orphaned young will be well cared for by other females. There are also species that readily share their food with those that are injured. Such caring ways aren’t something the average person typically associates with any bat species.

Group living has many benefits, but it also comes at a cost. A study of insect-eating bats in England finds that females and males often live at different altitudes, but can have surprisingly diverse mating behaviors.

Researchers observed the Daubenton's bat (Myotis daubentonii) and found at lower altitudes were mostly mama bats and their babies, while males dominated at higher altitudes. However, at intermediate heights, males and females were found cohabiting. These living arrangements reflect tradeoffs bats make for access to food, warmth and other resources, scientists reported. Most of the bats are segregated - males living apart from females - but also living together too. The bats probably segregate because there's not enough food to go around at higher altitudes. Mama bats need lots of nourishment when pregnant or nursing, so they can't afford to compete with the males. The male bats may opt to live alone to avoid the rampant parasites found in the close quarters of baby bat nurseries. In Michigan the bats give birth May through June, with both common species of brown bat producing one young. Young bats grow quickly and are able to fly within about three weeks. Both species of bats live approximately 6-7 years, and often until age 10. There have been a few documentations of little brown bats living over 30 years.

But the middle territory may be a happy medium where males and females can more easily satisfy feeding and mating needs.

While most of the bats live apart during the year, in late summer they congregate in droves near caves in a mating frenzy known as "swarming." The males just hang around night after night trying to pick up girls. Only a lucky few will become fathers, however, because the females only produce one baby at a time. The males that live together with females at the middle altitudes may have the best shot because they can mate with females even before they reach the caves.  In the spring, the females gather together in colonies known as nursery roosts, where each gives birth  in June. Naked and blind at first, the young bats grow quickly, nourished on a diet of rich milk from its mother. By August it is fully weaned and able to fly and forage for itself. In winter bats need cool sites with high humidity in order to conserve energy by slowing down their metabolism. Winter roosts include caves, tunnels, and old mine workings where they hibernate for up to 8 months.

Communication

The animal kingdom has a wide variety of communication that varies from species to species, but studies have shown that bats may have the most complex and intricate form of communication aside from humans. Some researchers “Translated" Bat Talk. It turns out they argue—A Lot. A machine learning algorithm helped decode the squeaks Egyptian fruit bats make in their roost, revealing that they “speak" to one another as individuals.

They found that the bat noises are not just random, as previously thought. They were able to classify 60 percent of the calls into four categories. One of the call types indicates the bats are arguing about food. Another indicates a dispute about their positions within the sleeping cluster. A third call is reserved for males making unwanted mating advances and the fourth happens when a bat argues with another bat sitting too close. The bats make slightly different versions of the calls when speaking to different individuals within the group, similar to a human using a different tone of voice when talking to different people. They point out that besides humans, only dolphins and a handful of other species are known to address individuals rather than making broad communication sounds. The research appears in the journal Scientific Reports.

Bats usually communicate with each other through high frequency chirps, screeches, and songs usually too high for humans to hear. And while we can hear sounds limited to frequencies between 20 and 20,000 waves per second, bats can emit and hear sounds at frequencies that are over 100,000 waves per second. The human ear can't naturally pick up the high-pitched sounds produced by bats, but we can hear those sounds that are within our wave frequency range. The ultrasonic sounds produced by bats can be recorded with special professional gear, and if you want to hear them, there are tons of good recordings available on the web. 

When "talking" to each other, however, the tones and calls are very different than the songs used for mating. Males marking their territory may use more aggressive and fiercer tones to keep other males away. Females also use different tones with each other than they would if they were communicating with males. The differences between male bat calls and female bat calls is distinct. Not only can bats detect the sex of the animal emitting the noise, but humans can decipher it as well. Most bats, whether they are communicating to predators, potential mates, or to their young, have a distinct style all their own.

Many species of bats rely upon echolocation in order to help them be able to locate their prey. They send out sounds and then wait for the echoes of them to come back. Bats communicate with their environment mostly by using their biological sonar. Like some birds, killer whales, dolphins and porpoises, bats use echolocation to navigate, detect food, and stay away from predators. Most North American bat species are insectivores, though we have three species of fruit bats in the US that migrate from Mexico.

By using echolocation, a bat will gather a huge amount of information about the space surrounding it. Echolocation will let a bat know about every obstacle in its path, the number of obstacles and how far they are from each other, as well as the size and shape of the obstacles. Its tiny brain will immediately calculate the exact point in time and space when it will have to avoid an obstacle, and how it will avoid it. It calculates speed, distance, and degrees while in flight better than any computer, being the most intensely studied animal in military aeronautical development. It eats in continuous flight, chewing and swallowing while continuing to successfully use echolocation.