Bats in a Cave Lab

At times, biologists need to estimate animal populations. Sometimes the numbers are so large or the animals are too difficult or dangerous to capture, that it is not practical or even possible to count each animal in the group. One method that is used to estimate a population of animals is called the capture-recapture technique. The first step is to capture and tag a known number of animals. These tagged animals are then released to mix with all the other animals in the region being studied. Samples of the animals are then caught, and the number of tagged animals in the sample is recorded along with the total number of animals in the sample.
Using the data from the experiment and proportions, scientists can estimate the total number of animals in the population.
In this lab, you will simulate (model) the capture-recapture technique for estimating the number of bats in a cave. Beans will be used to represent the population of bats and a bag will be used to represent the cave. Your job will be to estimate the total number of beans in the bag. The procedure for your experiment will be similar to the experiment described in the “Bats” story.