Wagging their tails

Question
How come my pig wags its tail ALL the time? Ive heard its when their happy, but even in situations when I know he cant be happy, hes wagging his tail?

Answer
Pigs wag their tails when they are excited and energized. Healthy young piglets wag their tails almost constantly. It's a sign that they are feeling well, alert, and interested in their environment. Excitement of any sort, such as frustration, anger or fear, also triggers piglets to wag their tails.

Contented, adult pigs wag their tails, too. Pigs wag when they are enjoying a rooting session, or just after rolling in mud or swimming in a pool. Pigs wags in any situation that might involve food. Adult pigs also wag when they are angry. When two pigs are about to charge each other, they frantically wag their tails.