The evolution of hominoid communication is evident through chimpanzee hoo vocalizations and alarm calls. Researchers propose that communication evolved as natural selection diversified hoo vocalizations into context-dependent hoos for travel, rest, and threats. Context-dependent communication is beneficial and likely maintained by selection as it facilities cooperative activities and social cohesion between signallers and receivers that can increase the likelihood of survival. Alarm calls in chimpanzees also point to the evolution of hominoid language. Callers assess conspecifics' knowledge of threats, fill their need for information, and, in doing so, use social cues and intentionality to inform communication. Filling a gap in information and incorporating social cues and intentionality into communication are all components of human language. These shared elements between chimpanzee and human communication suggest an evolutionary basis, most likely that the last common human ancestor with chimpanzees also possessed these linguistic abilities.