Are you curious about the differences between weasels and ferrets? In this article, we’ll dive into their contrasting characteristics and behaviors. Weasels, not domesticated, are smaller in size, measuring about 7-12 inches long and weighing around 1-2 lbs. Ferrets, both wild and domesticated, are larger, growing up to 20 inches long and weighing between 1.5-4 lbs.