Pig

The Pig is a passive mob that appears in Survival, Infdev,  and Indev mode. Pigs exist for the express purpose of providing health-replenishing food to the player. Pigs spawn in groups of three or four and wander aimlessly around a map. Though they are not hostile, pigs can bump into the player, possibly pushing the player over  a cliff to their death.

In Survival Test, Pigs can be killed to drop Brown Mushrooms.

In Alpha pigs eat mushrooms when they touch them, and they can also be  ridden via a saddle. The pigs cannot be controlled when ridden and are the only creature that can use said saddle.

Drops
Survival: Alpha:
 * 0-2 brown mushrooms
 * 0-2 pieces of pork