Why do swans put gesses under the water?

Swans often submerge their heads and necks in water to forage for food, such as aquatic plants, insects, and small fish. This behavior allows them to access nutrients and vegetation that are not available from the surface. By dipping their heads underwater, swans can also engage in preening, which helps maintain their feathers and waterproofing. Overall, this behavior is essential for their feeding and grooming needs.