The weasel family. Has Genera naturally occurring on all continents except for Australia and Antarctica (they have introduced to Australia by humans). All have 5 toes per foot, and sharp, non-retractible claws. Most mustelids have well-developed musk glands.
The mustelids are also notable for their mating habits -- the female must be properly aroused for ovulation. This is achieved by long (it can be hours) and rowdy mating. The male is aided in this by a baculum. During mating mustelids are more vulnerable to predators, but because ovulation is induced only during mating, fertilization is almost certain.
The Mustelidae has five subfamilies.