Pigs do grow hair in the eyebrow region, but it looks nothing like the distinct arches of hair that sit above human eyes. A prenatal hair development study that mapped hair growth across 17 body regions in pigs explicitly identified the eyebrow as one of those regions, alongside eyelashes and whiskers, finding that the brow area contained two to three distinct hair types.1Frontiers in Cell and Developmental Biology. Atlas of Prenatal Hair Follicle Morphogenesis Using the Pig as a Model System So anatomically, the answer is yes, but functionally and visually, pig “eyebrows” are so sparse and indistinct that most people would never notice them. The gap between what grows there and what we picture when we hear the word “eyebrow” is where things get interesting.
What the Pig Brow Region Actually Looks Like
When researchers talk about pig eyebrows, they mean the strip of skin and hair above the eye socket, not a conspicuous band of fur. In many pig breeds, the hair in this area blends seamlessly into the surrounding facial hair or skin. Pigs’ eyes are small and deep-set, which makes the brow ridge less prominent to begin with.2Journal of Animal Behaviour and Biometeorology. Neurological modulation of facial expressions in pigs and implications for production – Section: Neurological modulation of facial expressions Unlike humans, where the eyebrow sits on a relatively flat, exposed forehead and contrasts sharply with the surrounding skin, the pig’s brow area is tucked into a broader landscape of coarse facial hair, wrinkled skin, and a heavy skull. The hair that grows there is typically short and similar in texture to what grows on the rest of the head.
The prenatal hair mapping study found that eyebrow hair in pigs, along with head and beard hair, contained two to three different hair types, including guard hairs and finer undercoat fibers.3Frontiers in Cell and Developmental Biology. Atlas of Prenatal Hair Follicle Morphogenesis Using the Pig as a Model System – Section: Phenotype Measurement of Hair Shafts This is more hair type diversity than some other body regions, like the ears (which had only guard hair) or the eyelashes (which had only awl hair). So the brow region is doing something biologically, even if the result does not read as “eyebrows” to a casual observer.
Why Pig Eyebrows Are So Hard to Study
Researchers who work with pig facial expressions have run into a practical problem with the brow area. A study published in Scientific Reports that attempted to measure various facial features in pigs during social interactions found that eyebrow measurements could not be obtained at all. The reason was the combination of skin pigmentation in the brow area and image quality, which made the subtle brow region essentially invisible in photographs.4Scientific Reports. Facial expression as a potential measure of both intent and emotion – Section: Facial measures This is telling. In dogs, cats, and primates, researchers can reliably photograph and code eyebrow movements. In pigs, the brow area is so poorly defined visually that even controlled research photography cannot isolate it.
This does not mean pigs lack the anatomical structure. It means the structure is cryptic enough to be invisible to cameras and, by extension, to most human observers looking at a pig’s face. The brow region in a pig is functionally present but visually recessive, buried under pigmentation and sparse, nondescript hair. For breeds with dark skin around the eyes, particularly black-skinned breeds like the Berkshire or Large Black, the brow region is almost indistinguishable from the surrounding face.
No Muscle, No Movement
Even if you could clearly see a pig’s brow hair, it would not move the way human or dog eyebrows do. The expressive quality of eyebrows depends on underlying muscles that can raise, lower, and furrow them. Pigs have a well-developed set of facial muscles, but these are concentrated around the snout and lips. The primary facial muscle action in pigs involves the elevator muscle of the upper lip, which controls snout movements, and the musculature around the relatively short but mobile lips.5Journal of Animal Behaviour and Biometeorology. Neurological modulation of facial expressions in pigs and implications for production – Section: Neurological modulation of facial expressions There is no evidence of a specialized muscle dedicated to raising or lowering the brow in pigs the way there is in humans and certain other species.
This matters because what most people mean by “eyebrows” is not just hair above the eyes but the ability to move that hair expressively. Humans raise their eyebrows in surprise, furrow them in anger, and knit them together in concern. These movements are among our most important nonverbal signals. In pigs, the brow region sits still. Whatever communication pigs do with their faces happens lower down, through snout shape changes, ear posture shifts, and eye aperture.
How Dogs Got Expressive Eyebrows and Pigs Did Not
The contrast with dogs is revealing. Dogs possess a muscle called the levator anguli oculi medialis, which raises the inner eyebrow and produces the famous “puppy dog eyes” expression. Research based on dissections of dog and wolf heads showed that this muscle is uniformly present in domestic dogs but largely absent or reduced in grey wolves, suggesting it evolved specifically during the roughly 33,000 years of dog domestication.6PubMed Central. Evolution of facial muscle anatomy in dogs Dogs that could make this eyebrow-raising expression likely had a selection advantage because the movement mimics a sad human expression and triggers a nurturing response in people.
The story has gotten more complicated since that initial finding. A later study discovered that coyotes also have a well-developed version of the same eyebrow-raising muscle, which challenges the idea that dogs evolved it from scratch through domestication.7PubMed Central. Coyotes can do ‘puppy dog eyes’ too: comparing interspecific variation in Canis facial expression muscles The updated hypothesis is that the muscle may be an ancestral trait within the broader dog family that grey wolves specifically lost, rather than something dogs uniquely gained. Either way, the result is the same for dogs: they can raise their inner eyebrows dramatically, and pigs cannot.
Pigs were domesticated over a similar timescale as dogs, roughly 9,000 to 10,000 years ago. But the selection pressures were entirely different. Dogs were selected for social communication with humans, for reading human gestures and responding in kind. Pigs were selected primarily for meat production, growth rate, litter size, and temperament. There was no sustained evolutionary pressure for pigs to develop facial expressions that tug at human heartstrings. The pig’s face evolved for rooting in soil, not for looking soulful across a room.
How Pigs Actually Communicate With Their Faces
Without expressive eyebrows, pigs rely on other facial features to signal intent and emotion. Research measuring pig facial geometry during social encounters found that eye openness and snout shape carry meaningful information. Before initiating nose-to-nose contact with another pig, the initiating animal tended to have wider-open eyes compared to the non-initiator. Before initiating a bite, the aggressor had a more elongated snout ratio, meaning the distance between the eyes and the nose tip was relatively greater or the nose disk was flatter.8Scientific Reports. Facial expression as a potential measure of both intent and emotion – Section: Results These are subtle cues, far less dramatic than a raised eyebrow, but they are measurable and consistent.
Ears are the pig’s most visible emotional signal. A pig with ears pricked forward and upright is generally alert or in a more positive emotional state, while drooping or flattened ears often correlate with stress or negative affect. People seem to pick up on this intuitively. When shown photographs of pigs with different postures, study participants rated pigs with upright heads and raised ears as happier, though researchers caution that reliable indicators for actually identifying emotional states in farm animals do not yet exist.9PLoS ONE. Does picture background matter? People’s evaluation of pigs in different farm settings – Section: Discussion Vocalizations round out the picture: pigs have an unusually rich vocal repertoire for livestock, with distinct calls for distress, contentment, and social bonding. The face plays a supporting role, but it is the ears and voice that carry most of the communicative weight.
Why Humans Expect Eyebrows on Animals
Part of the reason “do pigs have eyebrows” is even a question is that humans are extraordinarily attuned to the eyebrow region when reading faces. Our brains devote disproportionate processing power to the upper face, particularly the eyes and brows, when interpreting emotion and intention. We project this bias onto other species constantly. People tend to interpret any marking or coloring above an animal’s eyes as eyebrows, even when the structure has nothing to do with expression. The dark patches above a Rottweiler’s eyes, the pale feathering above a penguin’s eyes, and the tufted hair above a cat’s eyes all get called “eyebrows” in casual speech because our brains want to map the familiar pattern onto every face we encounter.
This tendency leads to some amusing distortions in how people perceive pig faces. Certain pig breeds with lighter skin or contrasting facial markings can appear to have visible eyebrows simply because of pigmentation differences above the eye. A pink-skinned pig with a darker patch above the eye socket looks, to our primate brains, like it is wearing an expression. But the appearance of an eyebrow and the functional presence of one are different things entirely. The pig is not raising or lowering that patch of skin. It is just pigment sitting where our brains expect to see an expressive feature.
Breed Differences in Facial Hair and Appearance
Pig breeds vary enormously in how much facial hair they carry and how visible their brow region is. Heritage breeds with thicker, longer coats tend to have more noticeable hair in the brow area. The Mangalitsa, a woolly breed from Hungary, has dense curly hair covering most of its body, including a thick growth around the face that can look strikingly eyebrow-like in photos. Wild boar, the ancestor of domestic pigs, also carry denser facial hair than most commercial pig breeds, including more pronounced hair above the eyes.
Commercial pig breeds bred for intensive farming, like the Large White or Landrace, tend to have smoother, less hairy skin overall. In these breeds, the brow region is nearly bare, with only fine, barely visible hairs. The trend in modern pig breeding has been toward less body hair in general, partly because heavy hair coats complicate processing at slaughter and offer little advantage in temperature-controlled indoor environments. As a result, the eyebrow region in the pigs most people encounter, whether in person at a farm or in photographs, is at its most inconspicuous.
Research on pelage coloration in wild pigs and peccaries found that facial color patterns serve specific biological functions. Lighter faces are associated with larger species, and white facial spots correlate with living in less shaded environments and being active at night.10Oxford Academic. Ecocorrelates of pelage coloration in pigs and peccaries These markings are driven by camouflage and signaling needs, not by any communicative function in the brow region. A wild pig’s facial coloration evolved to match light conditions in its habitat, not to give it a more readable expression.
The Eyelash Situation
While we are on the topic of pig facial hair, eyelashes deserve a mention because they are often confused with eyebrows in animals and because they are more conspicuous in pigs than the brow hair is. The same prenatal hair study that confirmed eyebrow hair in pigs also found that eyelashes are present but consist of only a single hair type, awl hair, which is a straight, tapered fiber.11Frontiers in Cell and Developmental Biology. Atlas of Prenatal Hair Follicle Morphogenesis Using the Pig as a Model System – Section: Phenotype Measurement of Hair Shafts Pig eyelashes are typically pale and sparse but visible if you look closely, especially in lighter-skinned breeds. They serve the same basic protective function as in other mammals, shielding the eye from debris and helping direct airflow away from the corneal surface.
The whiskers, or vibrissae, around the mouth and jaw are the most prominent facial hairs on a pig and the ones that matter most functionally. These thick, stiff hairs are densely innervated and serve as touch sensors, helping pigs navigate their environment while rooting in soil or investigating objects in low light. Compared to the sensory importance of whiskers and the protective role of eyelashes, the hair in the eyebrow region seems to have no specialized function that researchers have identified. It may simply be a continuation of the general pattern of hair growth on the head, present because there is no reason for it not to be.
Why Pigs Look Expressionless to Us
The absence of visible, mobile eyebrows contributes to a broader perception problem that humans have with pig faces. We tend to find pigs harder to “read” emotionally than dogs, cats, or horses, and the brow region is a big part of why. Without the ability to raise or furrow their brows, pigs lack one of the primary channels through which humans subconsciously assess another creature’s mood. Combined with their small, deep-set eyes and the relative rigidity of their upper face, pigs can appear blank or inscrutable even when they are experiencing strong emotions.
This perception gap has real consequences for animal welfare. Research on how people evaluate pig welfare from photographs has shown that the emotional read people get from a pig’s posture and facial expression significantly influences their judgment about whether the animal is well cared for.12PLoS ONE. Does picture background matter? People’s evaluation of pigs in different farm settings – Section: Discussion If pigs’ faces are inherently difficult for humans to interpret, people may underestimate the emotional lives of pigs compared to animals whose faces are more legible to us. Researchers working in pig welfare science are increasingly trying to develop objective facial coding systems for pigs, measuring things like ear angle, eye ratio, and snout shape rather than relying on the human intuition that works so well for reading dog and human faces but fails with pigs.
The irony is that pigs are among the most cognitively sophisticated domesticated animals, capable of problem-solving, social learning, and complex emotional states. Their faces just do not broadcast those states the way ours do. The eyebrow, or rather its functional absence, is a small but telling part of that disconnect. We domesticated pigs for their bodies, not their faces, and their faces reflect that history.