tive experiments to clarify the role kinship plays in influenc-
ing social behavior. We also suggest that insight into the
evolution of specific social traits will best be gleaned by
mapping those traits onto more robust phylogenies. The
examination of intraspecific variation in social expression
should also prove informative, and we identify species that
will provide useful systems for such studies. Finally, we note
that cooperation in ground squirrels is not limited to ge-
netic relatives but expands with more complex sociality to
incorporate nonkin. Future investigations must also con-
sider societal benefits that accrue beyond lines dictated by
kinship.Ecology, Kinship, and Ground Squirrel Sociality: Insights from Comparative Analyses 355