In Leonardo da Vinci's Lady with an Ermine, an ermine is a small, graceful mammal characterised by its pristine white fur and distinctive, black-tipped tail. The portrait, created around 1488-1490, features Cecilia Gallerani holding this creature, symbolising her lover's loyalty. The ermine's elegant appearance and historical association with nobility add layers of meaning to the painting, showcasing Leonardo's keen attention to detail and ability to embed symbolism into his artworks.