
Structures built by animals, often called animal architecture, abound in nature. Examples include termite mounds, wasp and beehives, burrow complexes of rodents, beaver dams, elaborate nests of birds, and webs of spiders.

An ant colony is the basic unit around which ants organize their lifecycle. Ant colonies are eusocial, communal, and efficiently organized and are very much like those found in other social Hymenoptera, though the various groups of these developed sociality independently through convergent evolution. The typical colony consists of one or more egg-laying queens, numerous sterile females and, seasonally, many winged sexual males and females. In order to establish new colonies, ants undertake flights that occur at species-characteristic times of the day. Swarms of the winged sexuals depart the nest in search of other nests. The males die shortly thereafter, along with most of the females. A small percentage of the females survive to initiate new nests.

A nest box, also spelled nestbox, is a man-made enclosure provided for animals to nest in. Nest boxes are most frequently utilized for birds, in which case they are also called birdhouses or a birdbox/bird box, but some mammalian species such as bats may also use them. Placing nestboxes or roosting boxes may also be used to help maintain populations of particular species in an area. The modern nest box was invented by the British conservationist Charles Waterton in the early 19th century to encourage more birdlife and wildfowl on the nature reserve he set up on his estate.

Beavers are large, semiaquatic rodents in the genus Castor native to the temperate Northern Hemisphere. There are two extant species: the North American beaver and the Eurasian beaver. Beavers are the second-largest living rodents after the capybaras. They have stout bodies with large heads, long chisel-like incisors, brown or gray fur, hand-like front feet, webbed back feet and flat, scaly tails. The Eurasian beaver has a more elongated skull with a more triangular nasal bone opening, lighter fur color and a narrower tail. The animals can be found in a number of freshwater habitats, such as rivers, streams, lakes and ponds. They are herbivorous, consuming tree bark, aquatic plants, grasses and sedges.

A beehive is an enclosed structure in which some honey bee species of the subgenus Apis live and raise their young. Though the word beehive is commonly used to describe the nest of any bee colony, scientific and professional literature distinguishes nest from hive. Nest is used to discuss colonies that house themselves in natural or artificial cavities or are hanging and exposed. Hive is used to describe an artificial/man-made structure to house a honey bee nest. Several species of Apis live in colonies, but for honey production the western honey bee and the eastern honey bee are the main species kept in hives.

A bird nest is the spot in which a bird lays and incubates its eggs and raises its young. Although the term popularly refers to a specific structure made by the bird itself—such as the grassy cup nest of the American robin or Eurasian blackbird, or the elaborately woven hanging nest of the Montezuma oropendola or the village weaver—that is too restrictive a definition. For some species, a nest is simply a shallow depression made in sand; for others, it is the knot-hole left by a broken branch, a burrow dug into the ground, a chamber drilled into a tree, an enormous rotting pile of vegetation and earth, a shelf made of dried saliva or a mud dome with an entrance tunnel. The smallest bird nests are those of some hummingbirds, tiny cups which can be a mere 2 cm (0.8 in) across and 2–3 cm (0.8–1.2 in) high. At the other extreme, some nest mounds built by the dusky scrubfowl measure more than 11 m (36 ft) in diameter and stand nearly 5 m (16 ft) tall. The study of birds' nests is known as caliology.

A burrow is a hole or tunnel excavated into the ground by an animal to construct a space suitable for habitation or temporary refuge, or as a byproduct of locomotion. Burrows provide a form of shelter against predation and exposure to the elements and can be found in nearly every biome and among various biological interactions. Many different animal species are known to form burrows. These species range from small invertebrates, such as the Corophium arenarium, to very large vertebrate species such as the polar bear. Burrows can be constructed into a wide variety of substrates and can range in complexity from a simple tube a few centimeters long to a complex network of interconnecting tunnels and chambers hundreds or thousands of meters in total length; an example of the latter level of complexity, a well-developed burrow, would be a rabbit warren.

Dawnsong is a public artwork by American artist Brose Partington, located at Indianapolis Art Center in Indianapolis, Indiana, United States. Dawnsong was installed as part of the Center's ARTSPARK initiative.
A drey is the nest of a tree squirrel, flying squirrel or ringtail possum.Dreys are usually built of twigs, dry leaves, and grass, and typically assembled in the forks of a tall tree. They are sometimes referred to as "drey nests" to distinguish them from squirrel "cavity nests". In temperate regions, dreys become much more visible in the autumn, when leaf-fall reveals new nests built the previous summer or in early fall.
Otters are carnivorous mammals in the subfamily Lutrinae. The 13 extant otter species are all semiaquatic, aquatic or marine, with diets based on fish and invertebrates. Lutrinae is a branch of the Mustelidae family, which also includes weasels, badgers, mink, and wolverines, among other animals.

A nest is a structure built for certain animals to hold eggs. Although nests are most closely associated with birds, members of all classes of vertebrates and some invertebrates construct nests. They may be composed of organic material such as twigs, grass, and leaves, or may be a simple depression in the ground, or a hole in a rock, tree, or building. Human-made materials, such as string, plastic, cloth, or paper, may also be used. Nests can be found in all types of habitat.

A nest box, also spelled nestbox, is a man-made enclosure provided for animals to nest in. Nest boxes are most frequently utilized for birds, in which case they are also called birdhouses or a birdbox/bird box, but some mammalian species such as bats may also use them. Placing nestboxes or roosting boxes may also be used to help maintain populations of particular species in an area. The modern nest box was invented by the British conservationist Charles Waterton in the early 19th century to encourage more birdlife and wildfowl on the nature reserve he set up on his estate.

Nest-building in primates refers to the behaviour of building nests by extant strepsirrhines and hominid apes. Strepsirrhines build nests for both sleeping and also for raising families. Hominid apes build nests for sleeping at night, and in some species, for sleeping during the day. Nest-building by hominid apes is learned by infants watching the mother and others in the group, and is considered tool use rather than animal architecture. Old World monkeys and New World monkeys do not nest. It has been speculated that a major evolutionary advance in the cognitive abilities of hominoids may first have occurred due to the development of nest-building behaviour and that the transition from nest-building to ground-sleeping led to "modifications in the quality and quantity of hominid sleep, which in turn may have enhanced waking survival skills through priming, promoted creativity and innovation, and aided the consolidation of procedural memories".

A sett or set is a badger's den. It usually consists of a network of tunnels and numerous entrances. The largest setts are spacious enough to accommodate 15 or more animals with up to 300 metres (1,000 ft) of tunnels and as many as 40 openings. Such elaborate setts with extensive tunneling take many years for badgers to complete. One sett in Southern England spreads over an estimated area in excess of 2,000 square metres – precise measurement has not been attempted. Setts are typically excavated in soil that is well drained and easy to dig, such as sand, and situated on sloping ground where there is some cover.

Silkhenge structures are a means of spider reproduction used by one or more currently-unknown species of spider. It typically consists of a central "spire" constructed of spider silk, containing one to two eggs, surrounded by a sort of fence of silk in a circle.

Termites are eusocial insects that are classified at the taxonomic rank of infraorder Isoptera, or alternatively as epifamily Termitoidae, within the order Blattodea. Termites were once classified in a separate order from cockroaches, but recent phylogenetic studies indicate that they evolved from cockroaches, as they are deeply nested within the group, and the sister group to wood eating cockroaches of the genus Cryptocercus. Previous estimates suggested the divergence took place during the Jurassic or Triassic. More recent estimates suggest they have an origin during the Late Jurassic, with the first fossil records in the Early Cretaceous. About 3,106 species are currently described, with a few hundred more left to be described. Although these insects are often called "white ants", they are not ants, and are not closely related to ants.