Why do chickens and turkeys have white meat but ducks not?

The difference in meat color between chickens, turkeys, and ducks comes down to the type of muscle fibers they primarily use for movement.

* White meat is primarily composed of fast-twitch muscle fibers. These fibers are designed for quick, powerful bursts of energy, like flying short distances or sprinting. They rely heavily on glycogen for fuel and have a lower blood supply, leading to the lighter color.

* Dark meat is made up of slow-twitch muscle fibers. These fibers are meant for sustained activity, like walking or swimming long distances. They use oxygen more efficiently and have a higher blood supply, leading to the darker color due to myoglobin, a protein that binds oxygen.

Here's the breakdown:

* Chickens and turkeys: While both can fly, they are primarily ground birds. They rely on their legs for movement, which are primarily composed of fast-twitch muscle fibers, resulting in white meat.

* Ducks: Ducks are strong swimmers, requiring sustained effort to move through water. They use their breast muscles extensively for this purpose, and these muscles are mostly slow-twitch fibers, leading to dark meat.

It's important to note that even within a single species, there can be variation in the amount of white and dark meat. For example, a chicken raised for meat will have more white meat than a wild chicken, which uses its wings more frequently.