The term 'young seal' refers to three stages of a seal's life cycle. The first stage is the PUP, which is a baby seal that is 3 letters long. The second stage is the CALF, which is 4 letters long and is slightly older than the PUP. The final stage is the WHELP, which is 5 letters long and is the oldest of the three stages. All three stages are considered young seals and are characterized by their soft fur and playful nature.