This article does not have any sources. (January 2010)
A need is a thing that, when a living being, plant or animal does not have it, it is not able to live. A thing that someone wants to have, but is able to live when they do not have it, is called a want.
Every person has the same basic needs for the body. Humans have bodily needs of water, food, clothing, and shelter to live. The need for water is the most important because a person will die very quickly when they do not have drinking water. In a warm place food is the next most important need. In a cold place, the need for clothes or shelter may be next most important because a person will soon die when they do not have these.
Other human needs are not so certain. They are mostly needs for the mind. It is often said that a person needs love, family, and friends. These needs are for personal relationships. They may also be wants. It is true that a life may be better with these things, but some friends can be bad, or bad sometimes. Good relationships can make life very happy. Thinking about a need that is not possible can make a person very unhappy.
Some of the study of philosophy is about questions like "What are the needs of a human?"
Some scientists study the needs of human or animal minds and bodies. The study of the mind is called psychology - words about the mind. The study of bodily needs is part of medicine.