There is no such thing as a Miniature Collie. Not all Collies look like Lassie. The smooth Collie is identical in conformation to the rough, but it's outer coat is short, hard, dense and flat. Collies are loving, loyal, devoted companions. The Collie standard forbids any display of sulleness, timidity or viciousness, and it is extremely rare to find a Collie possessing these undesireable traits.
Collies are nibblers, particularly when in play or when exhibiting their herding traits.
They frequently nibble gently at their family as a sign of playfulness or affection, and this should not be misinterpreted as biting.