Sea otters are neither friendly nor unfriendly, they are simply wild animals.
People who interact with our otters are trained wildlife professionals. Play is a normal part of sea otter growth and development. Pups practice survival skills, like diving and cracking shellfish, when they play. They also learn to be part of the otter community by playing or interacting with other pups. Like any wild mammal, an otter will use its teeth to defend itself, especially when it's frightened or injured.