As field scientists, we don't always see gorillas, so we look for clues that tell us where the animals have been and what they were doing. And when we do see gorillas, we systematically record behavior we see or hear. One of the tools we use to do this is an ethogram. By using an ethogram, we can figure out how often and why gorillas do some of the things they do.

Here's how you can chart your own ethogram.

• Print out the ethogram chart.
• Review the behaviors by clicking the name of the behavior: knuckle-walking, eating, foraging, baby care, sleeping, tree-climbing, brachiating, grooming and playing.
• Based on what you have learned, predict which behaviors you will see most often and which you will see least often and write your predictions on the spaces provided on the chart. Think about why you made the predictions.
• Then, watch a video by clicking an image on the right. As you watch each video, make a mark on your ethogram each time you see a behavior. Some behaviors are performed more than once in the same video, some not at all. You may want to watch each video more than once to improve your accuracy.
• After you have watched the videos and recorded the behaviors, add up the number of times that you recorded each behavior. Enter your results on the graph at the bottom of the ethogram.
• Did your predictions match your results? Note on the chart which behaviors you observed most often and which you observed least often.
• When you're finished, compare your results to mine. Based on your observations what have you learned about the behavior of gorillas?