The sea otter is the largest member of the weasel family, yet the smallest marine mammal in North America. Otters have some interesting relatives. Otters are part of the Mustelidae family, which is a family of carnivorous mammals that includes skunks, weasels, wolverines, and badgers. If this southern sea otter looks comfy, that’s because it’s settling down to rest in a small patch of Egregia (feather boa kelp) at Moss Landing in California. Sea otters weigh more - around 45-90 pounds - with large, furry faces. River otters are much smaller - averaging 10-30 pounds - with a cylindrical body and small head. is home to two species: the sea otter and the North American river otter. Forget everything you thought you knew about otter species. Thirteen different species exist around the globe. We promise that you’ll be otterly entertained!ġ. Get ready for some awesome otter facts and photos. Held every year during the last week in September, Sea Otter Awareness Week spotlights the important role of sea otters in nearshore ecosystems of the North Pacific Ocean. Their charming features are unparalleled, from their expressions to their use of tools. Otters are some of the most adorable aquatic animals.