Some pinnipeds are a group of aquatic mammals that include seals, sea lions, and walruses. They are found in all oceans of the world and some species inhabit freshwater rivers and lakes. Seals are the most abundant and diverse of the pinniped species, with over 30 species living in the wild. They are typically characterized by their streamlined bodies, webbed feet, and fur-covered flippers. Seals are well adapted to life in the water, and they use their flippers to propel themselves through the water.