Dolphins are marine mammals known for their streamlined bodies, which help them swim efficiently in water. They have a layer of blubber beneath their skin that provides insulation and buoyancy. Their bodies are equipped with a dorsal fin on top for stability and pectoral fins on the sides for steering. Dolphins also possess a blowhole on the top of their heads, allowing them to breathe air while swimming. Dolphins have a complex skull structure that houses a large brain, which is associated with their high intelligence. Their teeth are conical and designed for grasping prey, as they primarily feed on fish and squid. The echolocation ability of dolphins allows them to navigate and hunt in dark or murky waters by emitting sound waves and interpreting the echoes that return.