The Differences Between Fur, Wool, and Hair

Humans have been making everything from household essentials such as clothes, blankets, and furniture to more indulgent items like wigs and toys using fur, wool, and hair for centuries. Despite their similar uses, these materials have different qualities, right down to their very fibers. Let’s break down the differences between fur, wool, and hair to help you find the right fabric for your next project or your new favorite winter coat.

Science vs. Colloquialism

Before discussing the differences between these materials, we must first separate science from colloquialism. In our everyday language, the terms fur and hair are interchangeable. However, from a scientific perspective, it really depends on what animal you’re talking about, as all three consist of keratin.

The main distinction is that in the English language, we refer to animal coats as fur; what grows on our bodies as hair, and only specific animals have what we call wool. We seem to define these words based on the bodies they grow on, what they look like, and how they feel. If we want to get down to the real nitty gritty, we must closely examine the fibers.

Fine Fur and Fibers

Animals that have fur have about three different kinds of fur: fur vibrissae, guard hairs, and under hairs, with guard hairs being what we recognize most often as fur. Human hair has a combination of guard hair and undercoat hair characteristics. Wool is a type of under hair with a notable curly texture that never really stops growing, as we purposefully breed sheep that produce this wool type.

Fur vibrissae, guard hairs, under hairs, and human hairs have relatively the same fibrous structures when breaking them down anatomically, with fur vibrissae being the only hair to have nerve endings. Wool is the only fiber that produces lanolin—a waxy substance—from their sebaceous glands instead of sebum, an oil. Additionally, the scales on the fiber’s cuticle have barbs. These barbs make dozens of tiny air pockets that trap heat, which makes it one of the warmest fabrics to wear in cold temperatures.

The Down and Dirty Difference

If you think that all this language and science is confusing, you’re certainly not alone. Many zoologists still argue about the true definition and categorization of these words and fibers. Suppose we really want to classify these materials beyond our common language and nit-picky science. In that case, we could argue that one of the main differences between fur, wool, and hair is their insulating properties.

As discussed, fur grows on humans and animals. Even though human hair evolved from animal fur, it doesn’t grow on us nearly as much as it used to or serve the same thermoregulating properties. However, animal fur grows in different layers that serve different purposes and keeps land and water mammals much warmer than us. Wool, whether alpaca, merino, or cashmere, seems to have the best thermoregulating properties, and depending on how barbed the fiber’s cuticles are, they can range from very coarse to very soft.

While we may never completely settle these definitions in our lifetime, it is fascinating to ponder what truly sets these materials apart.