Ducks swim because they have webbed feet. Webbed feet are feet that have webbing between the toes. This webbing helps ducks to spread out their weight and to propel themselves through the water. Ducks also have a thick layer of feathers that helps to keep them warm and dry in the water.
In addition to their wings and webbed feet, birds and ducks also have a number of other adaptations that help them to fly and swim, respectively. These adaptations include:
* A lightweight skeleton: Birds and ducks have lightweight skeletons that help to reduce their weight and make them easier to fly or swim.
* Powerful muscles: Birds and ducks have powerful muscles that help them to fly or swim.
* A streamlined body: Birds and ducks have streamlined bodies that help them to reduce drag and move more efficiently through the air or water.
* A long neck: Birds and ducks have long necks that help them to see over obstacles and to reach food.
* A keen sense of sight: Birds and ducks have a keen sense of sight that helps them to find food and avoid predators.
* A strong sense of hearing: Birds and ducks have a strong sense of hearing that helps them to detect predators and other animals.
These are just a few of the adaptations that help birds and ducks to fly and swim. These adaptations are the result of millions of years of evolution, and they have allowed birds and ducks to become some of the most successful animals on Earth.