A DIGESTION TRIAL ON BIG BROWN BATS

Photo courtesy of Sue Ellis

Overall health, long life, and reproductive success are the ultimate goals for captive maintenance of all animals. To reach these goals, sound nutrition is essential. Although the science of nutrition is based on the fact that all animals need the same broad groups of nutrients, each species has adapted uniquely to the problem of obtaining and utilizing the food it requires. Consequently, the feeding of unnatural foods, or even natural foods in an unnatural way, can produce unsatisfactory results. The question is to what extent? Therefore, how and what to feed insectivorous bats deserves close scrutiny.

Because it is impossible to duplicate the wild diet in captivity, captive diets have been designed that involve various preparation methods. Many of these preparations are in the form of "bat glop." Bat glop is essentially a puree of various dairy products, commercial baby foods, commercial cultivars of produce, and other commercially available foods. Although a puree may be convenient to feed, they have routinely produced unsatisfactory health response and longevity.

This digestion trial is multifaceted:

1) Two frequently debated captive bat diet preparations will be compared for nutritional suitability;

2) The ability of captive big brown bats to utilize the same nutrients offered in different forms will be evaluated;

3) A determination will be made on which dietary form most closely approximates the absorption levels of bats feeding on a wild diet.

A comparison of wild and captive diets may provide some valuable answers. The findings of this study will be published in appropriate, refereed journals, and updates will be shared with the Basically Bats membership.

1.  The first step in this project was to collect feces from wild bats.  Newspapers were placed under the roost, and the feces were collected daily.      Insect parts in the feces are currently being identified.  The feces are also being analyzed for nutritional content.  This information will be compared to the nutritional content of the feces of bats fed various captive diets. 2.  The next step was to locate the area in which the bats were feeding, in order to capture the bugs identified in the feces.  Bats had to be captured and fitted with radio transmitters.  A tube was constructed and placed over the bats' roost exit.

3.  After the bats were fitted with the radio transmitters, they were released to join their roost mates.  For approximately two weeks, the bats were tracked from their roost to their feeding grounds. 4.  Insect traps such as Malaise and multidirectional impaction traps will be placed where the bats were feeding.  The captured insects will be analyzed for nutritional content.

This and other research projects require funding.  Your tax deductible donation or membership to Basically Bats is greatly appreciated.

This page was updated by Tamara Romaine of

Page last updated 09 May 2004