As the chimpanzees became increasingly tolerant of their
human observers, it was possible to follow a select individual from the
time he or she left the sleeping nest in the morning until the time he or
she retired for the night. Typical “follows” last a few days,
with some exceptions. Researchers followed Melissa for 55 days after the
birth of her twins. When following, researchers collect data on the focal
individual’s behaviors and interactions with other chimpanzees. They
use the time interval technique, keeping a check sheet of behaviors observed
in minute-long time segments. Click
here to view the chart.