The human brain has evolved specialised neural mechanisms for visual recognition of faces, which afford us a remarkable ability to discriminate between, remember, and think about many hundreds of different individuals. Sheep also recognise and are attracted to individual sheep by their faces, as they possess similar specialised neural systems in the temporal and frontal lobes for assisting in this important social task, including a greater involvement of the right brain hemisphere.

K.M. Kendrick et al (Babraham Institute, UK) demonstrated that individual sheep can remember 50 other sheep faces for over 2 years, and that the specialised neural circuits involved maintain selective encoding of individual sheep and human faces even after long periods of separation.