Animals must do all they can to survive in the wild, and that often means sheltering themselves from predators or dangerous weather. Some animals are perfectly content with finding shelter such as caves, trees or old logs. Other animals would rather make their own shelters by digging holes in the ground or building nests in trees. These animals are examples of how intelligent wildlife can be, even if humans don't always give them enough credit.
Aside from humans, birds are known far more than any other animal for building their own homes. These homes are nests, and they can range from simple nests such as those made by adelie penguins (mounds of rocks placed on the ground to protect against flooding) to elaborate hanging nests such as those built by hummingbirds and warblers. They can be made from any material, but they are generally made from whatever is handy for the nest builders. Some materials used to make nests include twigs, straw, mud, stones and leaves. Some birds are even content to dig holes in the ground to use as nests.
Spiders are other creatures known for their ability to build impressive homes for themselves and their young. Nearly everybody knows that spiders can spin strong silk webs that can capture even large insects for food, and a complete spider web can indeed be an impressive sight. While many of these webs may not qualify as shelters because of the way so many are exposed to the elements, many species of spider are quite adept at building other structures. Most web-spinning spiders create egg sacs out of spider silk to store and protect their eggs much in the same way birds lay their eggs in nests. One fascinating species of spider is the trap door spider, which digs burrows underground and covers them with hinged lids.
Rabbits shelters are relatively simple burrows that are dug underground, but they can get quite complex when groups of rabbits live together. Groups of rabbits can create complex underground networks of burrows called warrens. These warrens can get quite large, consisting of several underground rooms. Like most animals that live in their own shelters, rabbit burrows and warrens are primarily used for protection against predators and for places where young rabbits can grow. The burrows are often lined with soft grass and fur, especially when there are homes to young rabbits.
Another animal known for its impressive home-building skills is the beaver. While some beavers live in burrows along the banks of rivers, most North American beavers live in lodges built from sticks, mud, and wood chips near rivers, lakes, and marshes. These lodges are dome-shaped structures that can get up to 10 feet tall. The lodges have one central chamber, and some of them have multiple entrances. They often are built just above the water on a river or lake, but wood chips line the floor to absorb moisture.