Adding sheep to the spectrum of comparative psychology
Marino & Merskin's comprehensive review of cognitive complexity in sheep is a laudable and important contribution to comparative psychology. It is also valuable because it shows promising directions for future research on this neglected species. The relatively small number of neurons in the bovid cerebral cortex indicates that sheep cognitive performance on traditional measures of complex learning is limited. Nevertheless, the social and emotional complexity of sheep underscores the importance of further research into domains including personality and psychological well-being.