Jordi Casamitjana, the author of the book “Ethical Vegan”, explains why vegans not only do not wear leather or wool but also reject any product made of “real” silk

I don’t know if I have ever worn any.

I have had garments of some sort that were very soft and silky (I remember one Kimono-looking robe I was given when I was a teenager as I had a Bruce Lee poster in my room which might have inspired someone’s gift) but they would not have been made of “real” silk, as they would have been far too expensive for my family then.

Silk is a luxury fabric that has been used to make clothing for centuries. Common clothing items made from silk include dresses, sarees, shirts, blouses, sherwanis, tights, scarves, Hanfu, ties, Áo dài, tunics, pyjamas, turbans, and lingerie. From all of these, silk shirts and ties are the ones I could have used, but I am not a shirt-and-tie kind of guy. Some suits have silk linings, but all of the suits I wore had viscose (also known as rayon) instead. I could have experienced silk bedding when sleeping somewhere other than my home, I suppose. Silk sheets and pillowcases are known for their softness and breathability and are sometimes used in expensive hotels (not the kind of hotels I frequent, though). Silk is also used to make a variety of accessories, such as handbags, wallets, belts, and hats, but I don’t think silk was part of any of the wallets or hats I have used. Home décor may be the other possibility, as some of the places I have visited might have had curtains, pillow covers, table runners, and upholstery made of real silk.

To be honest, how do you tell a silky fabric from another? I was never in a position where I had to do so…until I became a vegan over 20 years ago. Since then, when I encounter a fabric that could be made of silk, I have to check that it is not, as we, vegans, do not wear silk (the “real” animal one, that is). If you ever wonder why, then this article is for you. 

“Real” Silk Is an Animal Product


If you know what a vegan is, then you know the deal. A vegan is someone who seeks to exclude all forms of animal exploitation for food, clothing or any other purpose. This includes, naturally, any fabric that contains any animal product. Silk is entirely made of animal products. It is composed of an insoluble animal protein known as fibroin and is produced by certain insect larvae to form cocoons. Although silk as a fabric used by humans comes from farming particular insects (and insects are animals), the actual substance is produced by many invertebrates other than those farmed. For instance, spiders and other arachnids (this is what their webs are made of), bees, wasps, ants, silverfish, caddisflies, mayflies, thrips, leafhoppers, webspinners, raspy crickets, beetles, lacewings, fleas, flies, and midges. 

However, the animal silk humans use comes from the cocoons of the larvae of the mulberry silkworm Bombyx mori (a type of moth of the family Bombycidae) reared in factory farms. Silk production is an old industry known as sericulture that originated in Chinese Yangshao culture in the 4th millennium BCE. Silk cultivation spread to Japan around 300 BCE, and, by 522 BCE, the Byzantines managed to obtain silkworm eggs and were able to begin silkworm cultivation.

Currently, this is one of the deadliest industries in the world. To make a silk shirt, about 1,000 moths are killed. In total, at least 420 billion to 1 trillion silkworms are killed annually to produce silk (the number may have reached 2 trillion at one point). This is what I wrote about it in my book “Ethical Vegan”

“Silk is not suitable for vegans as it is an animal product obtained from the cocoon of the mulberry silkworm (Bombyx mori), a type of domesticated moth created by selective breeding from the wild Bombyx mandarina, whose larva weave big cocoons during their pupal stage from a protein fibre they secrete from their saliva. These gentle moths, who are quite chubby and are covered by white hair, are very partial to the aroma of jasmine flowers, and this is what attracts them to the white mulberry (Morus alba), which smells similar. They lay their eggs on the tree, and the larvae grow and moult four times before entering the pupae phase in which they build a protected shelter made of silk, and perform inside the miraculous metamorphic transformation into their fluffy selves … unless a human farmer is watching.

For more than 5,000 years this jasmine-loving creature has been exploited by the silk industry (sericulture), first in China and then spreading to India, Korea and Japan. They are bred in captivity, and those who fail to produce a cocoon are killed or left to die. Those who do make it will be then boiled alive (and sometimes later eaten) and the fibres of the cocoon removed to sell for profit.”

Silkworms Suffer in Factory Farms


Having studied insects for many years as a zoologist, I do not doubt that all insects are sentient beings. I wrote an article titled “Why Vegans Don’t Eat Insects”  in which I summarise the evidence of this. For example, in a 2020 scientific review titled “Can Insects Feel Pain? A Review of the Neural and Behavioural Evidence” by Gibbons et al., the researchers studied six different orders of insects and they used a sentience scale for the pain to assess if they were sentient. They concluded that sentience could be found in all the insect orders they looked at. The order Diptera (mosquitoes and flies) and Blattodea (cockroaches) satisfied at least six out of eight of those sentience criteria, which according to the researchers is “constituting strong evidence for pain”, and the orders Coleoptera (beetles), and Lepidoptera (moths and butterflies) satisfied at least three to four out of eight, which they say is “substantial evidence for pain.”

In sericulture, individual sentient beings (caterpillars are already sentient, not just the adults they will become) are directly killed to obtain the silk, and as the animals are reared on factory farms just to be killed, the silk industry is clearly against the principles of veganism, and not only vegans should reject silk products, but also vegetarians. However, there are more reasons to reject them. 

More research may be needed to prove it to the satisfaction of all scientists, but as the nervous system of the caterpillar remains totally or partially intact in many insect species during the metamorphosis process inside the cocoon, the silkworms are likely to feel pain when there are boiled alive, even when they are in a pupae stage. 

Then, we have the problem of rampant disease (something common in any type of factory farming), which seems to be a significant cause of silkworm mortality. Between 10% and 47% of caterpillars would die from disease depending on farming practices, disease prevalence, and environmental conditions. The four most common diseases are flacherie, grasserie, pebrine and muscardine, all of which cause death. Most diseases are treated with disinfectant, which may also affect the silkworm’s welfare. In India, around 57% of disease-loss deaths are due to flacherie, 34% grasserie, 2.3% pebrine, and 0.5% muscardine. 

Uzi flies and dermestid beetles may also cause silkworm deaths in factory farms, as these are parasites and predators. Dermestid beetles feed on cocoons on farms, both during pupation and after the pupa is killed by the farmer. 

The Silk Industry


Today, at least 22 countries produce animal silk, the top ones being China (around 80% of global production in 2017), India (around 18%), and Uzbekistan (under 1%). 

The farming process begins with a fecundated female moth laying between 300 and 400 eggs before dying, which then incubate for 10 days or so. Then, small caterpillars emerge, who are kept captive in boxes on layers of gauze with chopped mulberry leaves. After feeding from the leaves for about six weeks (consuming around 50,000 times their initial weight)  the so-called silkworms (although they are not technically worms, but caterpillars) attach themselves to a frame in a rearing house, and form a silk cocoon during the next three to eight days. Those who survive then pupate to become adult moths, who release an enzyme that breaks down the silk so they can emerge from the cocoon. This effectively would “spoil” the silk for the farmer as it would make it shorter, so the farmer kills the moths by boiling or heating them before they begin secreting the enzyme (this process also makes it easier to reel the threads). The thread will be further processed before it can be sold. 

Pretty much like in any factory farming, some animals are selected for breeding, so some cocoons are allowed to mature and hatch to produce breeding adults. Also like other types of factory farming, there will be a process of artificial selection to choose which breeding animals to use (in this case, the silkworms with the best “reelability”), which is what led to the creation of a domestic breed of silkworm in the first place.  

In the global silk industry, it has been estimated that the entire population of silkworms lived a total of between 15 trillion and 37 trillion days on factory farms, of which at least 180 billion to 1.3 trillion days involved some degree of potentially negative experience (being killed or suffering from a disease, which generates between 4.1billion and 13 billion deaths). Clearly, this is an industry vegans cannot support. 

What About “Ahimsa” Silk?


As happened with milk production and the disingenuously-called “ahimsa milk” (which was supposed to avoid cows’ suffering but it turns out that it still causes it), the same happened with “ahimsa silk”, another concept developed by the Indian industry reacting to the loss of customers concerned about the suffering of animals (especially their Jain and Hindu customers). 

Facilities claiming to produce the so-called ‘ahimsa silk’ say it is more “humane” than normal silk production because they only use cocoons from which a moth has already emerged, so no death supposedly occurs in the production process. However, deaths from disease caused by factory farming the moths still occur. 

Additionally, once the adults get out of the cocoon by themselves, they cannot fly due to their big bodies and small wings created by many generations of inbreeding, and therefore cannot free themselves from captivity (being left to die at the farm). Beauty Without Cruelty (BWC) has reportedly visited Ahimsa silk farms and noted that most moths that hatch from these cocoons are not fit to fly and die immediately. This is reminiscent of what happens in the wool industry where sheeps have been genetically modified to produce extra wool, and now require to be sheared as otherwise they would overheat.  

BWC has also noted that many more silkworms are needed in Ahimsa farms to create an equivalent amount of silk as conventional silk farming because fewer cocoons are reelable. This is also reminiscent of the cognitive dissonance some vegetarians have when they think they are doing a good thing by switching from eating the flesh of a few animals to consuming the eggs of many more animals kept on factory farms (who will be killed anyway). 

Ahimsa silk production, even if it does not involve boiling the cocoons to obtain the threads,  still relies on obtaining the “best” eggs from the same breeders to produce more silkworms, essentially supporting the entire silk industry, as opposed to being an alternative to it.

In addition to ahimsa silk, the industry has been trying other ways to “reform”, aiming at attracting back the customers they lost when they realised how much suffering it causes. For instance, there have been attempts to find ways to stop the metamorphosis of the moths after the cocoon has been formed, with the intention of being able to claim that there is nobody in the cocoon that will suffer when boiling it. Not only has this not been achieved, but stopping the metamorphosis at any stage does not mean the animal is no longer alive and sentient. It could be argued that when switching from caterpillar to adult moth the nervous system may “switch off” when transitioning from one type to another, but there is no evidence that this happens, and for all we know, it maintains sentience through the entire process. However, even if it did, this might be just momentaneous, and it would be very much impossible to find a way to stop the metamorphosis at that precise moment.

At the end of the day, no matter which reforms the industry goes through, it will always rely on keeping the animals captive in factory farms and exploiting them for profit. These alone are already reasons why vegans would not wear ahimsa silk (or any other name they may come up with), as vegans are both against animal captivity and animal exploitation.

There are plenty of silk alternatives that make vegans’ rejection of animal silk very easy. For example, many come from sustainable natural plant fibres (banana silk, cactus silk, bamboo lyocell, pineapple silk, Lotus silk, cotton sateen, orange fibre silk, Eucalyptus silk), and others from synthetic fibres (polyester, recycled satin, viscose, Micro-silk, etc.). There are even organisations which promote such alternatives, such as Material Innovation Initiative.

Silk is an unnecessary luxury item that nobody needs, so it is tragic how many sentient beings are made to suffer to produce its animal version. However, it’s easy to avoid the blood footprint of silk. Perhaps it’s one of the products most vegans find it easier to reject because, like in my case, silk may not have been part of their lives before they became vegan. Vegans don’t wear silk or have any product with it, but nobody else should either.

Silk is extremely easy to avoid.

Jordi Casamitjana
“Originally from Catalonia, but resident in the UK for several decades, Jordi is a vegan zoologist and author, who has been involved in different aspects of animal protection for many years. In addition to scientific research, he has worked mostly as an undercover investigator, animal welfare consultant, and animal protection campaigner. He has been an ethical vegan since 2002, and in 2020 he secured the legal protection of all ethical vegans in Great Britain from discrimination in a landmark employment tribunal case that was discussed all over the world. He is also the author of the book, ‘Ethical Vegan: a personal and political journey to change the world’.