The rabbit, when first upgraded, is perhaps the smallest animal in the game. It is also the first animal with a tail, which unlike most animals' tails, cannot be bitten by its prey. The body is colored in grayish-brown, with few decorations such as nubs for a nose and a tail, and two darker colored ears appearing as two ovals.
The rabbit is a very small animal, making it useful for you to pass through small spaces. If you ever encounter a predator, your best option is to run away, with your speed slightly higher than others; also, with your small size, you can go through tight spaces to avoid your predator.
The easiest way to level up is to find a berry bush, or Healing Stones. Either way, be wary of any predators, and albeit your ability grants you the ability to create temporary hiding holes, foxes can easily pull you out or other predators can wait outside your hole until it vanishes and you are exposed.
Mud, dominated mostly by pigs, can spawn in carrots in which a rabbit can eat. A mud spot unguarded by predators while having a handsome amount of carrots is an opportunity to upgrade to the next animal. A few carrots is enough to upgrade you from the rabbit to the pig, in which case, you can easily get resources from mud such as mushrooms and carrots. If you are in a predicament in which a predator has spotted you while in mud (usually pigs), burrow a hiding hole for a quick escape.