Squirrels and chipmunks look very similar and are often easily confused.

However, upon closer observation, you will notice the differences between them: compared to squirrels, chipmunks are smaller in size, have stripes on their heads, and have shorter tails. They also emit different sounds.

Chipmunks, squirrels, groundhogs, and prairie dogs are all members of the squirrel family. However, over millions of years of evolution, squirrels and chipmunks have become very different animals to adapt to various environments. For example, chipmunks spend most of their time on or below the ground, while squirrels prefer to stay in trees. Why is this?

This is closely related to how chipmunks and squirrels survive the winter.

1. Chipmunks have a varied diet, feeding on legumes, grains, cereals, and fruits. They invade fields in spring to dig up seeds of crops, and in autumn, they steal large amounts of grain using their cheek pouches. A storage space can hold 5-10 kilograms of food, occupying an area of up to 30 square meters.

They also climb trees to steal walnuts, apricots, apples, pears, etc. Due to their weak memory for food storage locations, they play a role in "seed dispersal" to some extent. They hibernate underground, and the entrance to their burrows is usually well hidden. Each burrow only houses one chipmunk, providing excellent security for chipmunks needing to hibernate.

Before the cold winter, chipmunks store plenty of nuts in their burrows and stuff their mouths with nuts. Then, they curl into a small ball, lowering their body temperature and heart rate. This way, when they need to wake up suddenly or feel cold, they can eat nuts to replenish their energy at any time.

When spring arrives in April of the following year, they suddenly wake up, and within two hours, their body temperature rises from 1°C to 37°C, and they begin to eat until the end of October when they enter hibernation again.

2. Squirrels are omnivores, eating various plants, including nuts, seeds, pine cones, fruits, fungi, green plants, and insects. They spend 70%-80% of their time foraging, preferring to forage and store food in coniferous forests.

In autumn, squirrels scatter nuts on the ground and store fungi on tree branches. Autumn caching is beneficial for squirrels to survive the winter and reproduce the following year. The microhabitat selection and re-caching mechanisms of squirrels have been extensively studied, becoming a hot topic in current squirrel ecology research.

Depending on the species and their environment, some squirrels hibernate while others do not. However, even for squirrels that do not hibernate, you may rarely see them in winter. This is because squirrels prefer to stay in trees, storing enough food to survive the winter. Occasionally, when they are active on the ground, they choose relatively safe areas under trees.

Squirrels' nesting habits sometimes utilize tree hollows and bird nests. Each individual typically occupies 2-3 nests simultaneously. Since fir trees have denser foliage than pine trees, squirrels usually nest in fir trees in artificial forests. There have been no reports on nest site selection in natural forests.

Most nests are built on branches 8-16 meters above the ground, near the trunk, or at branch forks, and are divided into two types: resting nests for daytime use and sleeping nests for nighttime use. They are usually spherical, about 30 cm in diameter, constructed of fine twigs, pine needles, and leaves, and lined with soft materials such as moss, leaves, pine needles, hay, and bark. Several squirrels may share the same nest in cold winters to maintain body temperature.