When gorillas that have been resting give "close calls" -- quiet grunts, grumbles, hums and whines -- they may be signaling their readiness to move on to another activity, suggest two UC Davis researchers. The signaling may allow the animals to indicate their tendencies and monitor those of others, say Kelly Stewart and Alexander Harcourt, UC Davis anthropology researchers. By providing information on what the gorillas will do next, the signals may synchronize the gorillas' activity and coordinate a departure from the resting site, the researchers suggest. Simple messages can produce complex social responses. For example, a message such as "I am hungry" results in the gorillas doing roughly the same thing at the same time and maintaining its group cohesion. Whether or not the meaning of the signal depends on the context of the situation or acoustical variation remains to be answered, the researchers say. Stewart and Harcourt will present their findings in the communication session on Thursday, July 29, 3:50 p.m., in Wellman Hall, Room 126.