more male gorillas sometimes vocalize together in a manner that perhaps
foreshadows human singing without words (gorillian chants?):One began hooting only to trail away to nothing before trying again.Then
another joined in,and a third one.Their clear hu-hu rose and fell as each stopped
and started independently.But when one reached a climax and beat his chest the
others followed.Then they usually settled down for a few minutes before repeat-
ing the whole procedure.(p.223)Chimpanzees are generally more gregarious than gorillas,and this is
reflected in their communication systems,which include rich repertoires
of facial,postural,and tactile expressions,similar to human body lan-
guage (e.g., chimpanzees and humans both greet conspecifics with
hugs and kisses).The auditory-vocal domain is where chimpanzees and
humans differ the most,although the former have a fairly elaborate
system of graded calls based on modifications of grunts,hoots,barks,and
screams (Marler,this volume) that express a variety of emotions ranging
from puzzlement to the appreciation of food.Different populations of
chimpanzees appear to have different accents,and adult males are
usually the most vocal individuals among both gorillas and chimpanzees.
For example,the long-distance pant-hoot is the most frequently used call
by adult male chimpanzees (see Ujhelyi and Geissmann,this volume).
These consist of a series of loud calls that are voiced on both inhalation
and exhalation,rising and falling in pitch,often ending with a scream.
Because primatologists are able to identify individuals on hearing
their pant-hoots,it is presumed that chimpanzees can too.In addition
to revealing locations of individual animals,long-distance pant-hoots
announce food sources or threaten individuals in other communities.
Goodall (1986:134) noted that pant-hoot choruses may break out during
the night,passing back and forth between parties that are sleeping within
earshot.Besides such “singing,”chimpanzees sometimes engage in drum-
ming displays by pounding hands and feet on large trees.Drumming is,
again,done primarily by males and is typically accompanied by pant-
hoots (Goodall 1986:133).Although chimpanzees are naturally chatty,
they actively suppress their vocalizations under some circumstances,such
as when males go on patrols of territorial boundaries.In sum,chim-
panzees engage in a rich variety of auditory communications.Their calls,
however,are not strictly referential,unlike vervet alarm calls,and this
fact more than any other reveals the limits of vocal communication in
our nearest nonhuman primate cousin (Mitani 1996).
These comparative observations,together with evidence pertaining to
the anatomy of the vocal tract (Frayer and Nicolay,this volume) and
cerebral cortex (Falk 1992a,b) of fossil hominids,allow one to form
reasonable speculations about auditory communication in our earliest210 Dean Falk