Q: Why do we say some animals have “hair” while others have “fur”?
A: All mammals have hair—dogs, cats, foxes, pigs, gerbils, horses, and people. Even dolphins have a few whiskers early in their lives. Scientifically speaking, there’s no difference between hair and fur.
“This is all the same material,” Dr. Nancy Simmons, a mammalogist with the American Museum of Natural History, said in a 2001 interview with Scientific American. “Hair and fur are the same thing.”
She added that there are many norms for hair length, and that different kinds of hair can have different names, such as a cat’s whiskers and a porcupine’s quills.
Well, science is one thing but common English usage is another. Most of us do have different ideas about what to call “hair” and what to call “fur.”
For example, we regard humans as having “hair,” not “fur.” And we use “hair” for what grows on livestock with thick, leathery hides—horses, cattle, and pigs.
But we generally use “fur” for the thick, dense covering on animals like cats, dogs, rabbits, foxes, bears, raccoons, beavers, and so on.
Why do some animals have fur and others hair? The answer lies in the origins of the noun “fur,” which began life as an item of apparel.
In medieval England, “fur” meant “a trimming or lining for a garment, made of the dressed coat of certain animals,” according to the Oxford English Dictionary.
The source, the dictionary suggests, is the Old French verb forrer, which originally meant to sheathe or encase, then “developed the sense ‘to line,’ and ‘to line or trim with fur.’ ”
When the word “fur” first entered English, it was a verb that meant to line, trim, or cover a garment with animal hair. The earliest OED use is from Kyng Alisaunder, a Middle English romance about Alexander the Great, composed in the late 1200s or early 1300s:
“The kyng dude of [put on] his robe, furred with meneuere.” (The last word is “miniver,” the white winter pelt of a certain squirrel.)
The noun followed. Its first known use is from The Romaunt of the Rose, an English translation (from 1366 or earlier) of an Old French poem. The relevant passage refers to a coat “Furred with no menivere, But with a furre rough of here [hair].”
The noun’s meaning gradually evolved over the 14th and 15th centuries. From the sense of a lining or trimming, “fur” came to mean the material used to make it. Soon it also meant entire garments made of this material, as well as the coats of the animals themselves.
Oxford defines that last sense of “fur” this way: “The short, fine, soft hair of certain animals (as the sable, ermine, beaver, otter, bear, etc.) growing thick upon the skin, and distinguished from the ordinary hair, which is longer and coarser. Formerly also, the wool of sheep” [now obsolete].
Note that this definition establishes the distinction between the special hair we call “fur” (short, fine, soft), and “ordinary hair” (longer, coarser).
The dictionary’s earliest citation is a reference to sheep as bearing “furres blake and whyte” (circa 1430). The first non-sheep example was recorded in the following century, a reference to the “furre” of wolves (Edmund Spenser, The Shepheardes Calender, 1579).
From the 17th century on, examples are plentiful. Shakespeare writes of “This night wherin … The Lyon, and the belly-pinched Wolfe Keepe their furre dry” (King Lear, 1608). And Alexander Pope writes of “the strength of Bulls, the Fur of Bears” (An Essay on Man, 1733).
But a mid-18th-century example in the OED stands out—at least for our purposes—because it underscores that “fur” was valued because it was soft and warm: “Leave the Hair on Skins, where the Fleece or Fir is soft and warm, as Beaver, Otter, &c.” (From An Account of a Voyage for the Discovery of a North-west Passage, 1748, written by the ship’s clerk.)
Elsewhere in the account, the author notes that deer or caribou skins were “cleared of the Hair” to make use of the skin as leather.
As for “hair,” it’s a much older word than “fur” and came into English from Germanic sources instead of French.
Here’s the OED definition: “One of the numerous fine and generally cylindrical filaments that grow from the skin or integument of animals, esp. of most mammals, of which they form the characteristic coat.”
The word was spelled in Old English as her or hær, Oxford says, and was first recorded before the year 800 in a Latin-Old English glossary: “Pilus, her.” (In Latin pilus is a single hair and pili is the plural.)
By around the year 1000, “hair” was also used as a mass or collective noun, defined in the OED as “the aggregate of hairs growing on the skin of an animal: spec. that growing naturally upon the human head.”
In summary, most of us think of “fur” as soft, cuddly, warm, and dense. We don’t regard “hair” in quite the same way (even though it technically includes “fur”). “Hair,” in other words, covers a lot more bases.
But in practice, English speakers use the words “hair” and “fur” inconsistently. People often regard some animals, especially their pets, as having both “fur” and “hair.”
They may refer to Bowser’s coat as “fur,” but use the word “hair” for what he leaves on clothes and furniture. And when he gets tangles, they may say that either his “hair” or his “fur” is matted and needs combing out.
Furthermore (no pun intended), two different people might describe the same cat or dog differently—as having “hair” or “fur,” as being “hairy” or “furry,” and (particularly in the case of the cat) as throwing up a “hairball” or a “furball.” They simply perceive the animal’s coat differently.
Our guess is that people base their choice of words on what they perceive as the thickness, density, or length of a pet’s coat. The heavy, dense coat of a Chow dog or a Persian cat is likely to be called “fur.” And the short, light coat of a sleek greyhound or a Cornish Rex is likely to be called “hair.”