Not to deliver it, but to take the package or envelope, check the address, then put it in a pile to go to a distribution center in the appropriate, proximal zip code of its destination. That done, the mail might wait up to a day to be flown out, two days at times, then another day to be delivered by ground.
Some breeds of dogs have a natural curl or bend to their tails. But others have been selectively bred to take this curl to an extreme, cork-screw shape. Dog breeds with curly tails referred to as screw tails include Boston Terriers, Pugs, Bulldogs and French Bulldogs.
Tail in the Air With a Curve. Cats will sometimes hold their tail in a way that resembles a question mark. The curve at the end of their straight tail expresses playfulness. They are feeling friendly and open to some activity.