There is now a vigorous debate over the evolutionary status of music. Some scholars argue that humans have been shaped by evolution to be musical, while others maintain that musical abilities have not been a target of natural selection but reflect an alternative use of more adaptive cognitive skills. One way to address this debate is to break music cognition into its underlying components and determine whether any of these are innate, specific to music, and unique to humans. Taking this approach, Justus and Hutsler (2005) and McDermott and Hauser (2005) suggest that musical pitch perception can be explained without invoking natural selection for music. However, they leave the issue of musical rhythm largely unexplored. This comment extends their conceptual approach to musical rhythm and suggests how issues of innateness, domain specificity, and human specificity might be addressed.