- Size: Male ducks are typically larger than female ducks.
- Color: Male ducks often have brighter, more vibrant colors than female ducks. This is especially true during mating season.
- Plumage: Male ducks often have more elaborate plumage than female ducks. For example, male mallard ducks have a green head, white neck ring, and brown body, while female mallard ducks have a brown head, white belly, and gray body.
- Voice: Male ducks typically have a louder, more distinctive voice than female ducks.
- Behavior: Male ducks are often more aggressive and territorial than female ducks.
- Anatomy: Male ducks have a penis, while female ducks do not.