Not Like Dogs
Ferrets are not pack animals like dogs and do not have the same instinct to protect a "pack." They are naturally curious and more likely to investigate a stranger than threaten them. They can be territorial about their space but usually respond with hissing or nipping rather than protection.
Signs of Attachment
Ferrets may get stressed when their owner leaves, become vocal or nippy toward strangers out of fear, or follow their owner around the house.
Individual Differences
Ferrets are not known for protectiveness in the way dogs are, but they can be very attached. Behavior varies by personality and experience.