A biome is a particular section of the world with a specific climate, home to particular mobs and containing particular resources. There are currently three biomes in starve.io: the forest, the winter/snow, and the ocean, with a fourth one (the desert) upcoming in future updates. The forest biome was the inaugural biome, and is currently located on the bottom left side of the map. Afterwards, the winter was added in the WINTER IS FINALLY HERE update, located on the top of the map. The newest biome, known as the ocean, is a large body of water, which contains six small islands, the only places where treasure chests can be found. The ocean biome is located in the bottom right part of the map and was added in the VAMOS A LA PLAYA update. Players start out in the forest biome, and generally move to the winter (or ocean) biome as they progress. Mob spawns and cold are based on the biome they are in.
The forest is the original biome that encompassed all of the map when the game came out. Currently, it covers about 1/4 of the map and is the smaller of the three biomes. The forest is the basis for survival, as it has a warm climate with relatively weak mobs.
The forest is advantageous for players because it is warmer. It also provides players with basic resources and food for survival. The forest is the only biome that allows players to plant berries, pumpkin and wheat without a plant plot.
The forest can be disadvantageous for players mainly due to the amount of players there. There is competition for resources and points. For example, players may take berries or gather gold right when you were going to, leaving nothing for you. Also, aggressive players would attack, chase, and possibly kill you so that they can have resources all to themselves, or simply because they want your points so they can get in the leaderboard or want to get items from your box after you die. If you want to avoid that, try going on servers with less people. Be careful though, you may lag a lot and still be chased. Also, the forest does not give the higher tier resources of diamonds, amethysts, dragon hearts, and winter fur etc.. Not to mention it is fairly hard to get water without going to a Lake, which is usually camped by other players.
The winter is a biome that was added in the WINTER IS FINALLY HERE update. It covers 1/2 of the map and is larger than the forest and ocean. The winter is much colder than the forest, and it is almost impossible to stay alive without using a chapka or fires. The winter is the stage for advanced players to obtain high tier resources, such as amethyst and the dragon heart.
Fun Fact: the nametag turns blue when a player goes into the winter.
The advantage of the winter is that there are fewer players and bases than the forest, and players can focus on survival. Also, the winter contains more powerful resources which increases the player's power. You can get resources more easily there due to how large the biome is, and because of the lack of players. You will also be able to obtain resources where you cannot find anywhere else, such as diamond, amethyst, winter fur, and dragon hearts. (Amethyst can be found in the Arctic biome's cave, dragon hearts can be obtained by killing the dragons that live in the cave, and diamonds are on both edges of the map).
The winter is extremely cold and has mobs that are challenging to kill without the right technique and equipment. Also there is no naturally spawning plants so a player would have to bring one over along with a plant plot in order to be able to plant anything. Since it is very cold you must be wearing a coat and you will have to put down many campfires to keep warm and survive, as well as have a large amount of food in your inventory.
The cave is located in the top right edge of the winter biome. The cave is guarded by up to 5 dragons. Amethyst and Dragon Heart resources are only obtainable in the cave. Since the cave is located very deep in the Arctic (in the top right corner of the map) you would have to travel across the Arctic for a long time in order to get there. Not to mention a player would have to avoid being killed by the dragons in the cave. Most players block off the dragons by using walls and hit the dragons through the wall by using a spear. when they don't intend to kill any dragons, they use an explorer's hat to get to the amethyst.
The ocean is the new biome added in the Vamos a la Playa (Spanish for "Let's go to the beach", and it is also a song) update.
Like the winter biome, there are barely any players here. Also, it is very hard to find someone's base given how expansively blank the ocean is (assuming you don't put your base on an island). The mobs can be really hard to kill however given how, once again, blank the ocean is, it will not annoy the average player too much. Also, it contains islands with treasure chests that can have rare items.
The ocean has few food sources other than hunting GMO Piranhas, with only two berry bushes. Also, it is very costly to build a base here, since you have to make a bridge for every place you want to build on the water, and you have to build plant plots in order to have a renewable source of food. This overall costs a lot of wood, unless if you build on one of the six islands.
The desert is an upcoming biome which will be added in the future. There is currently no official information on how and when it is going to be implemented. There are currently fan drawings of how it will look like, but none are confirmed to be implemented.