Leopard seals have variable spots, allowing for identification of individuals. In this latest research a subset of 40 spots on the face and neck of an adult female leopard seal residing in New Zealand (Owha) were monitored over time. Using images taken more than 4 years apart to see if the spots were more visible when the animal was wet or dry, and if they stayed constant.
The use of scars, acquired from wounds, allowed for cross-matching and confirmation that this was the same individual. The research found that all 40 spots were visible during this time period and when the animal was both wet and dry. However, they were better defined, and therefore more visible, when she was wet. Additionally, they identified a number of new and emerging spots, none of which masked or obscured the original ones.
So while a leopard seal can add new spots, they don’t lose the ones they have. Showing that photo-ID studies for the species are a robust system of identification and spot patterns are an effective tool for both individual identification and observing pigmentation change. However the research does suggest that care must be taken when matching individuals over long periods, to ensure that mis-matches and missed matches do not occur.