In Dōbutsu no Mori, the player arrives at a new town, which they name, and play as a singular character whose name they also choose. The game has no set goal; instead, it is more of a The Sims type of game, in which the player can do what they want, when they want, without rules, goals or time limit.
When the player first arrives, they will be given a house to live in. Unfortunately, they have no money, so they must pay off their home loan by earning "bells", the game's form of currency. Bells can be earned by performing various tasks for the other citizens of the town, catching and selling fish and insects, selling items, finding money in trees, and more. In addition to paying off the loan, money can be used to buy furniture and clothing. The player's home can see further expansions once the loan is paid.
One of the other main features of the game is the multitude of literally colorful characters that populate the town, all of whom are anthropomorphic animals; the player is the only human in sight. The town starts with a randomized selection of animal villagers, and more can move in and out as the game progresses. The player is able to talk to and befriend their animal neighbors.
The game uses an internal clock in the game pak to keep track of the date and time. Season changes and special holidays will occur in the town as time passes.