The five factor theory is used to organize and classify different human traits. This allows psychologist to more accurately verbalize and categorize people based on personality types. This theory breaks down into the following categories, neuroticism, extraversion, openness to experience, agreeableness, and conscientiousness. Neuroticism is how negative or positive your emotional state is. Extraversion describes how out going or shy one is. Openness to experiences is pretty self explanatory, it measures the degree you are willing to open or close your mind to new ideas. Agreeableness, describes how easy you get along with others. And conscientiousness describes how impulsive or self disciplined you are. These characteristics are pretty constant from birth but have been known to lessen as you age.
This Theory can easily be applied to other more primitive animals, and in past experiments it has been. There have been numerous experiments where animals, mainly chimps and other types of monkeys have been tested and classified using the five factor theory. It was found in most types of nonhuman privatives that traits associated with dominance was abundant, unsurprising as dominance plays a key factor in animal behavior. It was also found that conscientiousness in monkeys is a trait that increases as the subject ages. This along with open mindedness, and that monkeys in the a zoo habitat are more likely to exhibit open mindedness than one inside a lab.