Here's why:
* Young shoots: These are high in moisture, sugars, and nutrients, making them easier to digest and more palatable.
* Fresh, green leaves: While they are tougher than shoots, they still offer nutritional value and are more readily available than shoots.
Hard, dried-up yellowish bamboo is much tougher and less nutritious. Panda bears might nibble on it if they are desperate, but it's not their preferred food.
It's important to note that panda bears have specialized digestive systems adapted to digesting bamboo. They have a long digestive tract and strong jaws that help them break down the tough fibers.