Primal Magic can awaken animals and plants, granting them a human-level of intelligence, and the means to communicate. Primarily, animals are awakened by druids, and so most awakened animals are found in the Eldeen Reaches. There are many reasons that someone may choose to awaken an animal, whether for a specific purpose or just for companionship, but the skill and expensive material components required to do so mean it is not a step taken lightly. The vast majority of druids won't awaken an animal without reason (with the notable exception of the Greensingers.)
The Eldeen Reaches is home to the most Awakened Animals on Khorvaire, where they are integrated into communities and play many roles. Oalian's Voice is made up of awakened animals (many awakened by the great druid himself) who travel the Reaches, bringing news to the disparate communities in the Towering Wood and taking it back to Greenheart. The Bloodhounds are a corps of canines awakened by the Wardens of the Wood to help in maintaining order and solving crime.
And there are countless awakened animals that aren't directly associated with the Wardens of the Wood. Companions of druids, totems of local communities, or even those who were agents of the Wardens, but have since retired. The second largest source of Awakened Animals in the Towering Wood are the Greensingers, who awaken animals simply to bring more magic and whimsy into the world.