For humans, haircut, hairstyle, or hairdo normally describe cutting or styling head hair. Unlike other animals, human beings of many cultures cut their hair, rather than letting it grow naturally. Hair styles are often used to signal cultural, social, and ethnic identity and can be used to illustrate social status or individuality. Men and women naturally have the same hair, with the primary component of hair fiber being keratin. Keratins are proteins, long chains of amino acids. Generally, hairstyles conform to cultural influences of gender. Fashion trends may have a great influence depending on the person.