Before we can answer this question, we must define what is meant by thought. Thought can be defined in several ways; in particular, it is philosophical rumination and/or the processing of perceptions of the natural world. Because we are still trying to translate animal communication into human language, it is difficult to provide definitive proof of philosophical thought processes. Studies by animal behaviorists suggest that animals with a varied social life (such as chimpanzees) perceive the world in ways similar to humans. However, since we do not share a common verbal language with animals, it is impossible to know what they are truly thinking.