The biome that has squirrels, mice, rabbits, and deer is the temperate deciduous forest.

Here's why:

* Temperate deciduous forests have moderate temperatures and rainfall, making them ideal for a variety of animals.

* Squirrels, mice, and rabbits are all small mammals that thrive in these forests, finding food and shelter among the trees.

* Deer are larger herbivores that also flourish in this environment, feeding on leaves, grasses, and other vegetation.

While other biomes may have some of these animals, the temperate deciduous forest is the most likely habitat to have all four species together.