Silk

Silkworm
© Esin Deniz/Shutterstock.com

Written by Kyle Glatz

Updated: May 27, 2024

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Silk is a natural fiber produced by some arachnids and insects, and some of it can be processed into fabric. 

Understanding Silk

Silk is an animal-made protein fiber that has been used by humans as a source of textile material for thousands of years. The production of this material originated in China at some point during the 4th century BCE. The type of silk that is most commonly used to make textiles is primarily made from a protein called fibroin.

Many types of insects produce the substance, and they use it for different things. For example, web-spinning spiders make their webs out of this material. Spiders can produce different types of silk that help them perform many tasks. For example, some spiders use silk to produce a sticky web to capture prey while others use it to help them make balloons with which they can drift through the air.  

Mulberry silkworms are another creature that produce silk. These insects create the silk that is most frequently used in textiles. When these worms are ready to undergo metamorphosis, they will spin a cocoon. That is when these silkworms start producing threads of silk.

This material is very important in the animal kingdom. Yet, humans have also created large-scale operations to farm natural silk and generate artificial silk for use in clothing and decorations.

Joro spider in symmetrical web

Joro spiders can use web balloons to drift to far-flung areas.

©iStock.com/Jef Wodniack

What Animals Make Silk?

The mulberry silkworm is the most significant creature involved in the production of natural silk. These creatures are the larval form of the species Bombyx mori, the domestic silkworm. These insects are used for economically viable production instead of other members of the Bombyx genus. Still, silkworms are far from the only creatures that can make silk in the animal kingdom.

Examples of organisms that produce silk include:

Not every species of these organisms produces silk.

Animals that don't poop – silkworm

Silkworms are the most common creatures that produce silk.

©Deborah Lee Rossiter/Shutterstock.com

How Do Creatures Make the Thread?

Bombyx mori is the most common creature to produce the silk used by humans. They begin to create the the matieral when they are getting ready to pupate. These worms have two specialized salivary glands in their heads. Those glands take the proteins the worms obtain from feeding and help them turn a liquid into fine threads.

The worm excretes the liquid through its salivary glands. This liquid hardens into the threads as it comes out of the worm. Typically, the worm would continue to produce this material until it makes an entire cocoon. Then, the critter would undergo metamorphosis and emerge as a moth.

Other animals make silk in other ways. For example, spiders also have a liquid form of what will become fiber in their bodies. They produce the fiber from the spinnerets on their abdomens to make gossamer, their webs.

What Are the Uses of Silk?

Humans have used silk in many ways throughout history. In particular, the material that Bombyx mori make has been utilized for many purposes dating back thousands of years. Some of the most common uses of silk in the past and present include:

  • Surgical sutures
  • Shirts
  • Ties
  • Bowstrings
  • Pants
  • Bedding
  • Fishing lines
  • Furniture
  • Banners

The material’s inherent strength as a natural material makes it valuable. In the case of sutures, silk has been valued for its ability to be tied, its tensile strength, and its visibility against the skin.

Clothes and bedding made from this type of substance are lightweight, hypoallergenic, and soft. Also, the material’s distinct sheen provides a unique look for decorations.

This textile material is very versatile. However, producing silk is not always simple.  

How Do Humans Obtain This Product?

The production of silk as a textile has been ongoing for thousands of years, and evidence shows that the process first began in China. The desire to have more silk has led to an entire industry called sericulture. This industry first started thousands of years ago, possibly as far back as the Yangshao Period between 5,000 and 3,000 BCE.

Sericulture is silk farming, and it is a process that can have some variations to it. Generally, sericulture begins with having certain species of moths lay eggs in a controlled environment. The eggs mature and hatch into larvae that are then fed the mulberry leaves from which they derive the nutrition to produce liquid silk.

This process lasts for about 5 weeks until the larvae are ready to spin their cocoons and undergo metamorphosis. After they spin their cocoon, the silkworms are either boiled or steamed. This act preserves the fabric but kills the insect. Then, the cocoon is spooled, entwined, and threaded to make silk products.

Roughly 2,000 silkworms are harvested to produce every pound of silk on the market.  

Of course, humans also like the idea of creating artificial material that is not harmful to worms and can be produced faster and cheaper than farming. Some of these artificial substances use bamboo, lotus flowers, and other materials to make a similar fabric. Rayon is a semi-synthetic fiber that is similar to silk, and it is used for many of the same purposes as silk.

close up of Orizaba silkmoth

Silk moths start the sericulture process by laying eggs.

©iStock.com/LeoMercon


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About the Author

Kyle Glatz is a writer at A-Z-Animals where his primary focus is on geography and mammals. Kyle has been writing for researching and writing about animals and numerous other topics for 10 years, and he holds a Bachelor's Degree in English and Education from Rowan University. A resident of New Jersey, Kyle enjoys reading, writing, and playing video games.

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