Form and Function


            These bats are amazing creatures because like most bats they are nocturnal, which means they sleep for most of the day and come out at night to hunt for food. The Brazilian/Mexican free-tailed bat also is a relatively small creature that you can hold in your hand! Keep reading below to find out even more about this awesome species.


            Dental studies have determined that the longest living bat related to this species was over eight years old. That might seem very young but the longest living bat lived to be only twelve years old in captivity! Tadarida brasiliensis  is a relatively small bat, males are on average 23 mm and females 46 mm (Wilkins, 1989).  Although they may seem small and not have a long lifespans they do have very impressive adaptions to their environment that help them survive. Some of these adaptions include the development of using echolocation to communicate and physical adaptions such as stronger muscles to control flight speed.


            Brazilian/Mexican free-tailed bats begin foraging for food after sunset and feed all throughout the night. These bats can fly over 50 kilometers in order to reach a feeding area and at 3300 meters they have the highest recorded flight altitude among other species (Sosnicki, 2012). A recent observation in a Colorado mine discovered that these bats were most active in feeding and searching for new roost sites in the late morning and afternoon. It was also found that these behaviors occurred in the months of June through September because the seasons are beginning to change at this time. Brazilian/Mexican free-tailed bats have also been found to be social animals and tend to live in large colonies. (Sosnicki, 2012)

           In order to sense different stimuli and their environment these bats use a form of echolocation as their main mode of perception. Echolocation is a form of communication used mostly with bats but also seen with dolphins where the animal uses sonar in a call to detect the distance of objects. They also use this for detecting prey and navigation mainly because they come out at night for food (Sosnicki, 2012). This adaption has helped the bats when flying in the dark in order to detect prey as well as nearby objects so they do not slam into something. Bats use this form of communication and perception due to their poor eyesight. While adapting to hunting at night and having to find a more adaptive form of finding food (echolocation) bats may have began to lose their eyesight.

            The Brazilian/Mexican free-tailed bat does have morphological features that suggest adaptations for rapid flight. For instance these bats have short ears that lie against the head so they do not face the direct route air would move during flight. Wrinkled lips around the muzzle of the bat suggest an enlarged mouth opening for capturing insects and food to make up for their lack of maneuverability during high speed flight. Muscles are also very well developed in the wing membranes to tense different areas during flight in order to control flight speed (Wilkins, 1989). Muscles that are used mainly for flight are composed of fast oxidative fibers which represent an adaption for high speed flight for long periods of time. During colder months the Brazilian/Mexican free-tailed bat shows an ability to resist hyperthermia due to an increase of fat storage during season changes (Wilkins, 1989). When testing different reactions to environment change it was found that the Brazilian free-tailed bats could only survive without food and water for one-fourth to one-third the time of other hibernating species. It was found that the bats could survive three to four times longer at 27°C than other hibernating species though (Wilkins, 2012). This find could be a possibility for explaining how they can survive such cold weather due to a mechanism of greater body-water retention (Wilkins, 2012).

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