Bonobos, apes that closely resemble chimpanzees, live in dense
forests with faint trails in bands of more than 100 and each night rest
together in trees in a different spot.
During the day, they separate into small groups and forage for food,
often traveling for miles. When the day ends, they find their way back
together at a new resting place.
Ms. Savage-Rumbaugh said that in following the animals, she noticed
that whenever a trail crossed another trail, the lead group would stamp
down vegetation or rip off large leaves and place them carefully.
''What they are doing is leaving little notes in the vegetation,''
she said. ''Those notes are signals about where they are going to go.''
To prove her discovery, Ms. Savage-Rumbaugh said she twice followed
the trail signs far behind groups of the apes. At the end of each day,
she found her way to the reassembled band's new nesting trees.
Ms. Savage-Rumbaugh said it is impossible to study verbal
communications among bonobos in the wild because they vocalize only when
they are together in the trees. But captive bonobos, she said, have been
easily trained to respond to verbal language and to point to symbols
that have specific meanings.
