At one point or another, you've probably heard the old saying about "sending horses to the glue factory"
when they get old and sick. Jokes about making horses into glue pop up in places like the Simpsons,
and—shockingly—copious internet memes.
So if you've ever wondered if glue really is made from horses, you're not alone.
And if you've ever tried Googling it, get ready to hear an entirely different answer.
From the myths and facts about horse glue, to vegan glue options,
to how to tell if a product contains animal glue, I'm here to guide you through this sticky subject.
Hi, it's Emily from BiteSizeVegan.org, where you can find free resources, eCourses,
kids' content, and a Guided Search to help you find just what you need,
even if you don't know what to ask!
All my sources and additional info are available in this video’s article,
where I cover significantly more information than we're going to go through in the video.
So, to dive in deeper, go to bitesize.link/IsGlueVegan
So, is glue made from horses? Well, horse skin, bones, connective tissues, and hooves can be used to make glue.
However, while countless blog posts around the internet
claim that horses have been made into glue for thousands of years,
I could not find any solid evidence that horses were ever used more than any other animal.
In fact, horses were not even directly mentioned in any of the academic, industry, and historical-minded sources I read.
This is not to say that glue has never been made from horses—it has.
In fact, it's entirely possible that parts of horses slaughtered in today's horse meat industry
are used to make animal glue. But the idea that animal glue was—or is—primarily made from horses
is most likely a myth, overblown stereotype or—my personal guess—a manifestation of speciesism.
If you're not familiar, "speciesism" is “a prejudice or attitude of bias in favour
of the interests of one species and against those of other species.”
A simplified example is how we love dogs but eat pigs.
Speciesism presumes that humans determine the inherent value of other sentient beings.
In regards to this topic, our human bias for horses over those beings we deem "food animals"
became extremely apparent when I compared keyword research (meaning what people Google)
to academic research (meaning reality).
This may sound boring, but stick with me for a moment.
Pun intended.
As of this video, the phrase "is glue made from horses" is searched for 5,000 times a month,
while the phrase "is glue made from cows" receives 60 searches a month.
Even more telling, the phrase "is glue made from pigs" returned no data at all.
Yet, the reality is that most animal glue is made from cows and pigs slaughtered in the meat and dairy industries.
For an idea of the disparity, in the same year that 138,000 horses from the United States
were sent to slaughter, 34.2 million cows and 110.3 million pigs were killed in the US alone.
But, if you want clicks, you have to talk about what—or whom—humans care about,
which only continues to reinforce the valuing of some lives over others
—further pushing into obscurity the sentient beings we most exploit.
To learn about other false horse glue claims, the state of horse slaughter in the US,
and what happens to unwanted horses, please see the article for this video.
So, if not horses, what IS glue made of? And is it vegan?
These days, most glues you'll encounter are synthetic rather than animal-derived.
So yes, most glues are vegan. But animal glues and glues of animal origin are still manufactured.
While you would most likely know if you were purchasing hide, bone,
or fish glue in their pure form, you're more likely to encounter glues made from animals
within finished products like shoes, cosmetics, and musical instruments. Later on in this video,
we'll address how to tell if a product is made with glues of animal origin.
The history and modern technology of adhesives is more vast and complex
than I could possibly hope to cover. So, without breaking YouTube with a multi-day
adhesive treatise, let's explore a (very) abridged history of glue.
Glue is nothing new. Perhaps the oldest evidence of glue is a plant-based birch bark adhesive
dated back to the Middle Palaeolithic period.
In fact, birch bark glue may be the first known synthetic material our ancestors ever created.
Possibly the first known usage of animal glue dates back to over 8,000 years ago.
Early Egyptians used a range of glues of both plant and animal origin,
and the Greeks and Romans further refined and developed adhesives.
Roman naturalist Pliny the Elder wrote rather extensively about adhesives,
claiming that "The finest glue is made from the ears and genitals of bulls."
Jumping ahead to the 1100's - I did say this was an abridged history,
the pseudonymous author Theophilus, wrote instructions for preparing a variety of glues,
including those from fish bladders, cheese, animal skins, horns, and blood.
Fast forward to about 1690 when the first commercial factory for
producing animal glue from hides was set up in Holland.
A flurry of glue patents were issued after the first (for fish glue) was granted in 1754 in the UK.
The first animal glue factory was started in the United States in 1808,
and by 1900 there were multiple factories manufacturing glue from a variety of sources.
Up until the 1920s, most adhesives were either animal or plant-based in origin,
but the development of synthetic polymers rapidly overtook natural glues.
However, as glues of animal origin do still exist, we'll cover some of them.
Before we get into specific types of animal-based glues,
I wanted to note that nothing in my research has shown that animals are killed solely to make glue.
Animal glues primarily use parts of animals slaughtered for their meat,
or after their bodies give out from the demands of the dairy industry.
However, animal glue cannot accurately be deemed
"just a byproduct" of the meat industry. With a multi-billion dollar global market value,
there's no doubt that animal glue is a fully developed industry all its own.
So, animal glue—like leather—is a coproduct rather than byproduct
of the meat and dairy industries. To learn more about what a coproduct is,
check out my video and article "Is Leather a Byproduct of the Meat Industry?"
“Animal glue” technically refers to glues derived from mammalian collagen and keratin..
The most prominent animal glues are those made by extracting the collagen from animal skins,
bones and connective tissues through boiling.
Collagen is a fibrous structural protein present in the extracellular matrix and connective tissue of animals.
It's sometimes referred to as the "glue" that holds the body together.
Gelatin is essentially denatured collagen and is
"the purified active ingredient of any collagen-derived glue."
Hide glue—made specifically from animal skins —is said to be of higher quality than bone glue.
Most hide and bone glue is produced from cows and pigs slaughtered for their meat or after their bodies give out.
Rabbit skin glue is just what it sounds like—glue made from rabbit skin,
though other small mammals are sometimes included.
Less widely used animal glues are those made from extracting keratin—another structural protein
—by boiling hooves and horns. Hoof glue is still used in some woodworking,
though it seems more smaller-scale artisan woodworkers than commercial manufacturing.
Other glues of animal origin that don't fall under
the technical term "animal glue" include fish, casein, shellac, and albumin glues.
Fish glue can be produced from the skin of "non-oily" fish, along with their bones,
or from isinglass, a form of collagen procured from the swim bladders of fish.
Isinglass is more commonly used in the fining of some wine and beer.
See my article and video "Is Alcohol Vegan?" to learn more.
While Isinglass and fish glue may seem like niche products,
the impact of the global fishing industry is a threat to all life on this planet.
See my mini documentary "Empty Oceans" to learn more.
Casein is a protein found within milk,
and is originally what Elmer's glue was made with.
Casein glue is what Theophilus referred to in his 12th century writings as "the glue of cheese."
You may be more familiar with shellac as a finish for wood, or the shiny coating on candy and some fresh fruit.
Secreted from the female lac beetle, shellac is a resin
that can also be used for adhesive purposes, though its usage has declined due to its cost.
As we learned in the brief history of glue, blood albumin - a protein, and egg albumen
- what we call "egg whites", have been used to make glue, and may still be used in limited applications.
As I mentioned earlier, animal glue is still used in some modern manufacturing.
The best way to know if a product contains animal glue—or any animal-derived ingredients,
byproducts or coproducts—is to contact the company.
I will say that this can be a frustrating—if not fruitless—endeavor depending on the company.
If in doubt, see if there is an alternative product that you can verify,
but don't lose yourself in tracking down every adhesive in every product.
Oftentimes, the information isn't even available. When it comes to necessary prescriptions that may contain gelatin,
please refer to my video and article "Is Medication Vegan?"
Overall, focus on the big things. When buying actual glue, buy vegan.
These days, you kind of have to make an effort not to!
As we learned in our abridged history,
the first known glue was entirely plant-based. Long before the advent of synthetic glues,
natural adhesives were made from a variety of non-animal sources. While most commercial
glues are now petroleum-based, natural plant-based glues are still in use today.
There is a developing interest in (re)expanding
the usage of bio-based polymers for their environmental advantages over synthetics:
they're biodegradable, non-toxic, and are said to have lower carbon footprints.
Starch is an inexpensive and abundant natural polymeric carbohydrate found in plants.
Dextrin is simply starch that's been further processed.
For adhesives, starch is most commonly derived from maize, corn, potatoes, rice, and wheat.
Starch glues are commonly referred to as "paste," and are widely used in bonding paper
products as well as in textiles. Due to their many advantageous attributes over synthetics,
starch and dextrin-based adhesives still hold their own in a largely synthetic market.
Cellulose is "the most important skeletal component in plants." In the glue-world,
cellulose adhesive is use for such applications as wallpaper,
window decals and apparently to secure the packaging of cigarettes.
Natural rubber is sourced from certain trees and plants, and used primarily in pressure-sensitive adhesives.
While natural rubber is plant-derived,
there is serious concern over deforestation, environmental impact, and sustainability.
As I stated early on, the world of synthetic adhesive is far beyond the scope of this video.
If you really want to dive in, feel free to read one or more of the multi-hundred-page textbooks in my bibliography!
At a very high-level, most synthetic glues are petroleum-based.
So while animal-free, there are issues of environmental sustainability.
Synthetic glues include everything from pressure-sensitive adhesives made with
synthetic rubber, to two-part epoxies, to hot glue, to contact cement, and countless others.
Rather than get lost in a chemistry lesson,
let's touch on which major glue types and brands are vegan.
Let's tackle the biggest one first: Elmer's Glue. Elmer's glue is vegan,
though it wasn't originally. First produced by the Borden Company, a conglomerate with its roots in the dairy industry,
Elmer's was casein glue - made from milk.
Despite the bull mascot on the bottle, it was never made with horses, hooves, hides,
or other animal components. Elmer the bull is simply the "husband" of Borden Dairy's mascot,
Elsie the cow. Modern Elmer's glue is entirely synthetic.
Other common glues that are animal-free include:
Super Glue, Krazy Glue, most eyelash glues - which is apparently a thing, and Gorilla Glue
—a company which actually affirmed the inherent rights of animals when replying to an inquiry.
For more specifics on vegan glues, check out the article for this video.
It's time to "stick" the landing of this subject - couldn't help myself.
Here's the major takeaways:
The myth of horse glue is likely driven by the fact that we humans care more about horses
than the cows and pigs most animal glue actually comes from. When it comes to buying glue, you're likely clear of animals.
When it comes to pre-made products, do your best and find alternatives if possible.
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Now go live vegan, and I'll see you soon.