Now this is something new. While GTA V has collided with the world of educational wildlife commentary before, it hasn't ever quite done something like this. The two wildlife documentaries which have been made for GTA V by 8-Bit Bastard are extremely well made and entertaining, however both of them are scripted and heavily edited. Neither of these things are bad, mind you, but what Deer Cam is doing is something else entirely.

GTA V has seen some experimentation before, such as the social experiment using the players of Online as subject, or the video observing the game when the player character is inactive. This one involves a lot more outside influence than those and rather focused on the fundamentals of AI coding.
Deer Cam is a Twitch stream which is following the adventures and misadventures of a deer in GTA V. This particular deer is a very special, modded deer. One of the player characters of the game has been replaced with the model of a deer, which is also autonomous. The deer moves on its own, picks its own directions, reacts dynamically to the world around it — in one word, it's smart. There is no-one controlling it, no one sitting in front of the PC.