Seal Identification

Each grey seal has a unique pattern in its fur that it keeps for life. This enables us to learn about our seals as individuals in a completely non invasive way.

We take photos of the left and right profiles of seals we see on land and in the sea and build up photo identification catalogues for the different sites that seals choose to visit. Each seal is allocated a unique code and multiple tags reflecting the shapes we can see in their fur patterns enabling us to search our catalogues quickly and easily.

Lewis ID


To confirm a seal identification, a minimum of five exact fur pattern matches are required in the same relative positions, preferably from both sides of the seal and the rest of the seal’s pattern must be consistent. Once two surveyors are in agreement, the match is recorded in our database from which sightings histories for individual seals can be generated.

Links are routinely made between catalogues allowing us to remotely track seals around our coast. Hundreds of different seals have been identified at multiple sites.