McGrew reviews two books addressing what lies behind the behavior of nonhuman species. Griffin\u27s book caused considerable discussion when it first appeared five years earlier. The book has become the cornerstone of a new discipline – cognitive ethology. Three new chapters (on mental experiences, semantics, and evolutionary continuity) have been added to the original eight in the first edition. Almost a third of the cited studies have appeared since the first edition\u27s publication, illustrating the unexpected richness of the new findings. Griffin emphasizes that animal communication is the richest source of material, leading to inferences about animal minds. Griffin is careful not to overstate his case. Hall\u27s book is very different, and the two books, while focusing on more-or-less the same topic, could not be more different. However, McGrew argues that both books challenge the long-held assumptions about the mental lives of other species. Direct evidence of animal mental lives may be hard to find, but even the most prudent interpretation of the new research raises ethical implications
