Seal Society of San Diego- Differences between seals and sea lions

Both are Pinnipeds, “fin-footed”, with a common ancestor, Enaliarctus Mealsi, a big otter-like creature who lived millions of years ago. As such, seals and sea lions are considered to be in the seal family. Both are warm-blooded mammals and produce milk. A layer of blubber or fat insulates both sea lions and seals from the cold water.