Well, because dogs are descended from ancient gray wolves, who were food cachers themselves.

额，因为狗是古老的灰狼的后裔，而灰狼本身就是食物储藏者。

Dogs are descended from ancient gray wolves, who were food cachers themselves, and it seems that instinct never went away, even after all these years spent as a pet out of the wild.

狗是古老灰狼的后代，而灰狼本身就是食物储藏者，即使这些年来不在野外作为宠物度过了如此漫长的岁月，其本能似乎也从未消失。