Bagworms are really moths the caterpillar cloths itself with fragments of the plants on which it feeds. Inside this it changes to a chrysalis and the female moths never leave it, the males having to seek them out and mate with them while they are still in this protective bag.

Corals are polyps that build a massive internal skeleton of a chalky matter which is secreted from their tissues. In contrast the fan worm is a very skillful builder which fashions a tube by cementing sand grains together. It picks up each sand grain with its lips, moistens it with saliva an places it in position as a bricklayer would a brick, thus building a kind of circular tower around itself.

Some of the protozoans called formainifera build a sort of shell by cementing together grains of sand or even sponge spicules as in this case. Using available materials instead of manufacturing them saves an animal a good deal of effort and energy.

The shipwarm is a mollusk which has an elongated body and borrows in timbers submerged in the sea including the timbers of wooden ships. The larva settles on the surface of the wood and with two shells on the front of its body it rasps tunnels through the wood always working along the grains.

In spring the Pacific giant salamander burrows at the base of a spring emptying into a stream to create an underground pool. In this it mates, the female lays her eggs and the larvae spend the rest of the summer in it.

The scarab beetle not only excavates a cavity in the ground but fashions a sphere of dung which it then rolls along the ground and into the cavity. A sphere is the most difficult form to model but the beetle manages this successfully.

Although the rabbit has only weak front feet it excavates enormous burrows by scraping away the earth with the front feet and pushing it backwards with its strong hind feet. A colony of rabbits may excavate numerous tunnels in a bank which is then known as a warren. Some larger warrens have been known to extend nearly a quarter of a mile.

Wasps and bees are well known for building elaborate nests. Mostly they use wood chewed up an mixed with their saliva to form paper. Mud Wasps use mud in much the same way, using their saliva as a cement and adding the materials layer by layer so that the nest is marked with growth lines. The organ pipe mud wasps build a long pendulous cylinder and several of these together look like organ pipes. The nest is solely to house the egg and larvae. It is not a home.

Wasps also live in societies each society comprising the offspring of a single queen. Their nest is a bag which is made up of several layers of paper and inside it are several tiers of cells, each cell also being made of paper. The queen wasp starts the nest an the workers continue it by chewing fragments of wood from tree and converting them with their saliva into paper.

Ant lions are the larvae of insects which look something like small dragonflies. The larvae lives in sandy places and digs funnel shaped pits in the sand. there they wait for insects to fall into the pit where they seized by the jaws of the ant lion.

The larvae of the caddis fly live at the bottom of ponds or streams, carrying their homes about with them. Recent research has shown that the caddis fly larvae must build as a long as its body is naked, but once it is clothed as far as the head, the impulse to build dies down. This is what governs the length of the tube. The Larvae of the caddis fly lives in tubes which they make by gluing grains of sand or pieces of leaf together.

The fox squirrel lives in the eastern United States and nests in hollow trees or in nests made among branches an fashioned of leaves an twigs in the manner of other squirrels.

Flying squirrels of North America usually take over deserted holes of woodpeckers and line them with shredded bark and dry leaves and then make an inner lining of soft materials such as moss, feathers an fur. Sometimes they make an outside nest of sticks an line it in the same way. Squirrels build bulky nests of twigs and leaves which are called dreys. Some nests are used merely for resting and sleeping but others are used for nursery nests for the young.

All spiders produce silk. Some merely lay a trail of silk as they move across the ground but orb spinners, including the garden spider, build a beautiful geometric web as a snare to catch insects.

The water spider builds the prototype of the diving bell. It makes a thimble shaped bell of silk attacked by strands of silk to the submerged parts of water plants, the mouth of the bell being directed downwards. The bell is filled with air. To do this the spider goes to the surface, pushes the top of it’s abdomen into the air, traps a bubble of air among hairs on its abdomen, swims down to the bell and releases the air inside it.

Trapdoor spiders live under ground in a tunnel lined with silk. At the surface the entrance of the tunnel is closed with a lid. The spider must come out of its tunnel to catch insects but retires into the tunnel afterwards for protection. This means that the lid must not only efficiently hinged but must be a very close fit.

The wood duck makes a smaller nest than most other ducks, the chief feature of which is the way it lines the nest with feathers. That is the limit of building skill of the duck: many ducks will make their nest in hollow trees using a cavity already in existence an the wood duck does this more than most.

To protect its eggs from too much water or too little, the Brazilian tree frog builds a mud nest about a foot across an three or four inches deep. This miniature pool holds the eggs and a small amount of water.

Sand martins nest in sandy banks or sandy cliffs, excavating tunnels each of which goes up to three feet into the bank horizontally. This is a remarkable achievement because the bird has only a small beak and relatively weak feet to use in the excavation.

The caterpillars of many moths spin silken threads which are woven into a cocoon as the caterpillar rotates. The cocoon is waterproof an because of the air trapped among the fibers, the chrysalis into which the caterpillar turns lives at a constant temperature. The cocoon is a wonderful protection, the caterpillar uses to defend itself from parasitic invasion.

Pocket gophers build labyrinths of tunnels six inches to a foot below the surface of the ground. In tunneling the gopher throws the earth behind it, then makes a right turn and bulldozes the earth to the surface with its head and front paws.

This Malayan soldier crab feeds by sifting sand, taking in the edible material and casting aside the indigestible sand as pellets. It feeds when the tide is out and when the returning tide approaches. It also uses sand pellets to build an igloo around itself.

Approach a sand crab an it will try to take refuge in its burrow, but if intercepted it will dodge away an with astonishing speed race across the sand. They are also called ghost crabs, for on twilight nights they look pale and ghostly.

Leaf cutter ants can cause havoc in plantations when the workers sally forth and cut pieces out of leaves. These pieces are taken back to the nest where they are used as a compost for growing fungus on which the ants feed. Some of the nests built by these ants are of enormous size. One was said to have been twelve yards across.

Each colony of termites builds a high mound of mud cemented with saliva that becomes so hard that a pick is needed to break its surface. Inside the mound is riddled with tunnels but there is an orderly system about the tunnels which produces the perfect air conditioning. The mound is therefore not only impervious to water but is kept at a constant temperature.

The paper Nautilus is related to squids an octopuses but swims freely in the sea. It has no shell like that of the pearly nautilus, but if she is mated the female makes a paper thin white shell for reception of her eggs. This is secreted an fashioned by two of her arms which are much enlarged and flattened.

Sea lampreys move up rivers at breeding time, the males going first, followed later by the females. The males select a suitable depression in a sandy bed and removes any stones that maybe in the way. These stones are carefully collected and placed along the sides of the trough as a sort of protective wall. After the eggs have been laid and fertilized, both parents cover them over with sand and stones. The adults then leave and die.

Stink bugs are also known as shield bugs. They manufacture nothing and to protect their eggs and young larvae, the female uses her own body. she lays a batch of eggs on the underside of a leaf an then remains covering them with her body until they are old enough to shift for themselves.

Male sticklebacks construct nests of water reeds the three spinned species build on the bottom, the ten spinned off the bottom, among reed stems. When the structure is finished, the male tries to lure as many females as possible into it. After the young hatch, the male remains on guard.

The saying is “To eat somebody out of house and home.” The leaf miner does the reverse. as it eats the sift tissues at the middle of a leaf it creates a tunnel which becomes its home during its larval life.

Most species of orioles use long fibers in weaving their sac-like nests and sometimes create hundreds of intricate loops and knots during the construction. Eagles build a substantial nests of twigs and sticks in a tree or on a cliff.

The blue jay of North America is a woodland species which likes open forest but also takes up residence in parks and suburbs in cities. Like all members of the crow family, it builds a substantial nest of sticks. It is a notorious robber of other birds nests bu protects its own by building it among dense foliage.

Gannets live in colonies on islands. The nests are closely packed on the flat top of the cliff, each nest only about a foot from it’s neighbour. The nest is an untidy mound of seaweed with a saucer shaped depression in the top.

The long billed marsh wren lives among the reeds ant cattails of salt and freshwater marshes of North America. Wrens build large bulky nests, domed at the top and with a side entrance. This is the work of the male, the female merely lining the nest one she has chosen it. The urge to build is so strong in the male wren that he builds several nests, only one of which is used.

The Leach’s petrel spends most of its time at sea, coming to land only to breed. the nest is made at the end of a tunnel, but like the majority of birds which nest in tunnels the nest is no more then bare ground.

Burrowing owls are found on the American prairies. They nest in small colonies, each pair digging a small burrow with their long legs. the nest is also used for resting during the day.

Weaver birds are well known for their unusual nests which are most carefully woven and complex. For their size, they build some of the largest nests in the world. Some of the sparrow sized species construct nests as large as tents.

The female horn bill creates a prison for herself by building a brick hard wall across the nest opening. The male feeds her through a small hole. This wall protects her while incubating eggs, rearing young, and moulting her flight feathers.

The prairie dog is a foot long rodent living on the prairies of middle west United States. It used to be found in colonies numbering hundreds of millions all burrowing in the ground. These burrowed areas are known as towns and one town in 1901 was estimated to cover 100 by 240 miles and to contain 400 million prairie dogs.

Moles are probably the world’s best tunnelers, building elaborate underground “highway systems”. One individual made 302 mounds in seventy seven days. Grass lined chambers harbor young and sleeping adults. A Mole tunnels through the earth using its front feet as a combination of pick an shovel. Having loosened the earth it then turns around an pushes the earth out to the surface with it’s snout. Where moles are numerous the ground beneath the surface becomes a labyrinth of tunnels.

The chipmunk is a ground squirrel which excavates tunnels in the ground. A tunnel may reach thirty feet long and have several rooms. Two or three of the smaller rooms are for storing food. The rest are used for sleeping quarters and one is used for toilet purposes.

The white throat-ed wood rat is also known as the pack or trade rat because of its propensity for taking bright objects but always leaving a stone in place of the object it steals. These objects are carried back to its ome, which is a bulky structure made of any litter rubbish, but particularly of sticks, and looks like a badly built beaver lodge.

The Raccoon of North America is remarkable for using it’s toes as fingers to hold its food. It is even said to be able to untie knots in string. Yet it makes no attempt to build an sleeps in a hollow log or a cavity in the rocks.