Sheep Remember 50 Faces for 2 Years as Brain Cells Encode Individuals

1 articles · Updated · spacedaily.com · Aug 20

A 2001 Nature study found sheep could remember about 50 individual faces for more than two years, challenging the view of sheep as interchangeable followers.
Twenty sheep were trained on 25 pairs of face photographs linked to food rewards, then kept identifying the correct faces long after training ended.
Single-cell recordings in visual-recognition brain regions showed some neurons responded most strongly to particular familiar faces, pointing to circuits tuned to known individuals rather than faces in general.
Researchers and later reviewers said that memory appears to fade gradually—from recognition of a specific individual to a broader sense of familiarity—though that mechanism remains a proposed model, not a settled fact.
The work suggests sheep have durable social memory and some human-like face-processing organization, but later commentary cautioned that similarities to human recognition may be overstated.