Wolf

Wolves are neutral mobs that were added in Update 0.9.0. You can be tame them by feeding them Bones. They were the first tameable mob in the game.

Wild
Wild wolves spawn in Taiga, Plains, and Forest biomes. They wander aimlessly, but will sometimes coordinate and kill Sheep. When doing so, they will gain the appearance of aggressive Wolves.

Aggressive
Wild Wolves may turn hostile towards the player if they, or nearby Wolves are attacked. Aggressive Wolves have red eyes and black patches on their fur. Their tail is also raised higher than wild Wolves.

Tamed
Tamed wolves follow the player around the world, and teleport towards the player if they are too far. Tamed wolves are tamed using bones, and shake themselves dry after exiting any body of Water. They can be made to sit and stand by pressing the 'sit' or the 'stand' button (or by tapping and holding on them with an empty hand) respectively. They can be healed by tapping and holding them with any type of meat. Their collars can be dyed by pressing them with any Dye. By default, the collar is red, as of 0.11.0.

Breeding
Tamed Wolves can be bred using any type of meat (raw beef, pork chop ect.) if their health is fully restored, including Rotten Flesh, which will not poison them. However, they cannot be bred by using Fish. When bred, a puppy spawns, which is already tamed.

Wild Wolves cannot be breeded until tamed.

Combat
Tamed Wolves attack any mob the player attacks or attacks the player, and will attempt to kill it. Wolves can easily kill Skeletons, Zombies and Spiders, but face trouble against Creepers and Endermen, the former due to their explosive power and the latter due to their high health and teleporting ability.

Trivia

 * In early 0.9.0 beta builds, tamed Wolves had a black collar.
 * After 0.11.0, Wolves' collars became dyeable.
 * Hostile wolves will make growling sounds at the player.
 * Some players prefer to call tamed Wolves 'dogs'.
 * Tamed Wolves can enter love mode while sitting.
 * However, they cannot breed until they are made to stand.
 * Also, Wild Wolves can be fed but they can't breed.
 * Before Update 0.10.0, Baby Wolves couldn't swim in deep water and would drown.
 * After Update 0.12.1, Wolves will attack Skeletons, as they want Bones.
 * After Update 0.13.0, Wolves will attack Sheep and Rabbits.