For example, hoofed animals with longer necks could reach the juiciest leaves on tall trees and therefore tended to eat well, live longer, and reproduce more successfully than others.

• 例如，脖子较长的有蹄动物能够吃到高树上的嫩枝嫩叶，因此与同类相比更容易吃得好、活得长、有更多的后代。