Why and how do spiders spin threads?

Spiders are able to spin threads through their finger-like organs called spinnerets, and they can produce a substance that is called spider silk. Researchers estimate that for a given diameter, their tensile strength can be higher than that found in steel. Some spiders utilized this strong silk for constructing symmetrical fly-trapping webs, but almost all of them use it mainly for mobility, where they can sail or ‘’balloon’’ on winds using the substance.

Airborne spiders are known to land on ships that are sailing 300 kilometers off the land, and they have been found reportedly on altitudes of 3,000 meters. To help them navigate in the air, spiders would spin draglines, which are at least two or four or more silken threads that are meshed closely together. On vertical surfaces, these spiders use the threads like how a mountain climber uses a rope. The silk is anchored safely to a surface at intervals via specially fabricated attachment disks, giving the animal both guidance and a safety rope that prevents it from falling should the surface ahead prove to be impassable. Encountering danger, the spider usually maneuvers in midair while assured that the dragline would bring it back towards the surface. Wherever spiders go, they would leave a silken trail behind. The strands of silk we encounter floating between objects are relics of their impressive ballooning flights, which are gossamer draglines that were discarded once they have served their purpose, and the spider has moved to another location. In the open air, these strands are soon brushed or blown away, but in seldom-frequented places, the threads would typically accumulate in the familiar sheets and nonsymmetrical masses of silk that we call cobwebs.

For you to better imagine how a spider does the ballooning technique, you should take a look at how the superhero Spider-Man maneuvers in his city. He would often shoot a strand of thick silk to the top of a building before swinging it forward. A spider performs that technique to move to another location, but it does not fall downwards, as it only moves forwards because it is obviously lighter than the Marvel superhero.

Because of the amazing tensile strength of spider silk, they would sometimes use to protect their bodies, as well as their eggs, against predators. Biologists believed that this was the first purpose of spider silk, and they eventually began to use it for hunting prey once they discovered that it is sticky enough to trap insects that they can eat.

Different species of spiders have developed different ways of creating spider webs. The most common is the spiral orb webs that are created by the Araneidae, Uloboridae, and Tetragnathidae family. The second type is the funnel web, while the third is the tangled web that is produced by the family Theridiidae. The fourth type is the sheet web, and the last one is the tubular web that is seen as vertical strands on trees.

There are also several different types of silk produced by spiders, but the most common ones are the sticky silk and fluffy silk. Some researchers have speculated that the various types of silk arose as spiders needed to capture stronger prey in the wild, as these animals have evolved to counter the strength of primitive silk.

Spider silk is also used not only by spiders but also by humans since the 16th century. One of the first human uses of spider silk was for cobweb paintings, which are created by putting layers of colored cobwebs on a canvas or any other flat surface that can be painted on. Because cobweb paintings are fragile in nature, only a few of them exist today, with some of them being handled by private collectors who know how to keep them in almost pristine condition. In Europe, bundles of spider silk are used to heal wounds, and this utilization is possible since spider webs are typically rich in Vitamin K that helps clot blood much faster. Some people would even produce a pad made out of spider silk to cover wounds more effectively while also stopping the bleeding on the injured or wounded area. Today, spider silk is being studied for the purpose of using it to create bullet-proof vests.

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