A hairy business

Let your hair down: 10 amazing facts about human hair

Image: Ali Pazani

The human body is incredible, from its mechanics to its ability to heal and adapt to multiple environments and situations. Hair, as part of our body, is no exception to this complexity and wonder. Let’s take a look at 10 amazing facts about our hair that you may not know!

Image: Ian Talmacs

The word hair is used to describe two separate and distinct components: the follicle and the shaft. The follicle—what we commonly refer to as the root—is a living organ located in the dermis of the scalp. It’s responsible not only for growing hair but also for helping regenerate skin after a wound.

On the other hand, the shaft—often referred to as the strand—is a filament composed of layers of keratin, the same protein that makes up our nails. Unlike the follicle, the hair shaft is technically dead because it consists of dead cells.

Image: Joyful Bird

Each hair strand is composed of three layers. The innermost layer is the medulla, and even scientists are still uncertain about its exact function. Surrounding the medulla is the cortex, which absorbs water and provides strength to the strand. The cortex also contains melanin, the pigment that determines hair color, and its shape plays a major role in whether hair is straight or curly. The outermost layer is the cuticle, which serves primarily to protect the hair shaft.

Image: Tyler McRobert

Hair color is primarily influenced by several genes, including MC1R, which plays a key role in melanin production. However, not everyone produces the same type or amount of melanin. Higher amounts of melanin result in black hair, while varying levels and types of melanin—along with genetic variations—produce brown, blond, and other shades.

Red hair, the rarest natural color, is caused by a mutation in the MC1R gene and is inherited in a recessive pattern. This means a person must inherit two copies of the mutated gene (one from each parent) to have red hair, though many people carry the gene without expressing the trait.

Image: William Warby

Growing at a rate of about 0.2 to 0.5 inches per month, hair is the second-fastest growing tissue in the human body—surpassed only by bone marrow. This rate is influenced by factors such as genetics and ethnic background. Other variables, such as age, lifestyle, or health, can also have an impact on our hair growth and density.

Image: Sohan Rahat

We usually think of cats or dogs when it comes to shedding, but humans also shed hair regularly. After all, hair is a trait shared by all mammals. The average person sheds between 50 and 100 strands of hair per day, though this number can increase in response to stressors such as illness, hormonal changes, or emotional stress. Once the stress subsides and the body readjusts, the excess shedding typically stops.

Image: Joseph Chan

Commonly associated with aging, grey hair isn’t a color in itself but rather the result of a loss of pigment. As part of the natural aging process, melanin production in the hair follicle gradually decreases and eventually stops, causing strands to appear grey or white.

Genetics and ethnic background play a major role in determining when and how the greying process begins. Some people are even genetically predisposed to start greying at a very young age.

Image: Jaroslav Devia

Hair texture is commonly associated with ethnic background, but that’s not the only factor involved. Texture is primarily determined by genetics, and while genetics are closely tied to ancestry, all hair textures can be found across different populations.

Scientists believe that hair texture—specifically curl pattern and volume—is a result of the shape of the shaft. A round shaft typically produces straight hair, while flatter or more oval-shaped shafts tend to create curls and waves.

Image: Amritanshu Sikdar

Depending on the structure of your hair cuticle, your hair may be more or less water-repellent. Hair shafts with a more porous cuticle absorb water easily but also lose moisture quickly. In contrast, shafts with a tighter-packed cuticle struggle to get wet and are slow to dry.

Image: Sonja Langford

Hair doesn’t grow continuously or all at once—each strand follows a cycle with distinct phases. First comes the growing phase, which varies depending on the type of hair (for example, facial hair grows faster and for a shorter period than scalp hair). Eventually, growth slows down, and the strand detaches from the root.

After this, the hair enters a resting phase, during which it remains in place until it is naturally shed. At any given time, we have hairs in all stages of this cycle, which is why we regularly shed hair without going bald.

Image: Hans Reniers

Like any other part of the body, hair contains DNA and genetic material, which means a person can be genetically identified from a single strand, provided it includes the root. But hair holds even more information. The analysis of a hair strand can reveal substances that were present in a person’s bloodstream over time, including vitamins, minerals, medications, alcohol, and other substances.

Blame evolution: 10 reasons why cats are (not) the worst pets

Cats often get a reputation for being difficult, distant, or unreliable pets. People who grew up with dogs sometimes describe them as cold, stubborn, or uninterested in pleasing anyone. This list looks at familiar cat behaviors that can feel frustrating at first, especially to new owners. Seen more closely, these same traits help explain why cats fit comfortably into many homes and why millions of people continue to choose them as companions year after year. Continue reading to discover that your cat truly loves you!

Calling a cat by name and getting no response is a common experience. Unlike dogs, cats rarely come running just because they are called. This can feel dismissive, even rude, to owners who expect a pet to respond on cue.

What’s often overlooked is that cats evolved as mostly solitary hunters. They did not develop social behaviors centered on following leaders or responding to group signals. Studies and everyday observation show that cats can recognize their names and the sound of their owner’s voice, but they decide for themselves whether to react or not. For many people, this independence means fewer demands for constant interaction and a pet that is comfortable spending time on its own.

Many cat owners know the sound: a slow tap, a pause, and then a cup or pen sliding off the edge of a table. Cats often push objects while watching closely, as if waiting for the result.

This behavior is tied to curiosity and learning. Cats use their paws to test how objects move, whether they roll, wobble, or fall. This kind of testing is connected to hunting instincts, where judging motion and distance matters. While it can be annoying, it also shows that cats stay mentally engaged with their environment instead of simply reacting to commands or routines.

Some cats appear deeply committed to a favorite chair, window, or room, while paying less attention to following their owners around the house. This can be mistaken for emotional distance.

In reality, cats rely heavily on familiar spaces. Territorial behavior is well documented in feline behavior, and known areas provide safety and predictability. Many cats show affection by choosing to remain near trusted people within these familiar spots. Staying close without constant contact is often how cats express comfort and attachment. It looks like indifference. It usually isn’t.

Cats can learn routines, such as using a litter box or recognizing feeding times, but they rarely perform tricks or tasks simply to please people. Compared to dogs, they are often labeled "untrainable." Domestication helps explain this difference. Cats were domesticated much later than dogs and retained more independent behavior. Dogs were bred over thousands of years for cooperation with humans, while cats largely adapted themselves to human environments. For many owners, this means living with an animal whose behavior feels consistent and self-directed, rather than shaped by constant training.

Adult cats sleep a lot—often 12 to 16 hours a day. This pattern comes from their natural rhythm as predators that conserve energy between short periods of activity. Instead of constant attention-seeking, cats rest when nothing demands their focus. For many households, this makes cats easier to live with, especially for people who value quiet or spend part of the day away from home.

Cats frequently refuse foods that dogs would eat without hesitation. They are obligate carnivores, meaning their bodies are designed to rely on nutrients found primarily in meat. They require specific amino acids that plant-based foods do not provide. Their selectiveness reflects a digestive system shaped by evolution, not stubbornness. Once owners understand this, feeding routines often become simpler and more predictable.

Every new couch seems to be noticed immediately. Scratching furniture is one of the most common complaints about cats: sofas, chairs, and rugs often suffer. Scratching serves several purposes. It helps cats stretch muscles, maintain claw health, and mark territory using scent glands in their paws. While scratching can damage household items, the behavior itself supports physical comfort and well-being. Providing appropriate scratching surfaces allows cats to meet this need without constant correction.

Some cats nip during play or petting, especially when stimulation becomes too intense. It feels personal, but it rarely is. In many cases, cats show subtle warning signs first, such as tail flicking, ear movement, or muscle tension. Overstimulation, particularly around sensitive areas like the tail or lower back, triggers these reactions. Owners who learn to read these signals often find that cats communicate boundaries clearly and consistently.

Cats are often active early in the morning or late at night, which can interrupt your sleep. This crepuscular pattern comes from hunting instincts, as small prey animals are active at those times. Even indoor cats retain this rhythm. While it doesn’t always align with human sleep schedules, it also means cats can go about life without constant attention during the day, when many households are busiest.

Cats may ignore attention for long periods and then suddenly want closeness. This shift can feel confusing or inconsistent. They usually approach people when they feel calm and secure. Affection offered on their terms often feels different—and more noticeable—than affection given on demand. For many owners, these moments feel meaningful precisely because they happen by the cat’s choice rather than by routine or training.