Fear is something we feel instinctively and is known to protect us from danger. However, phobias have very little do do with physical danger and is more about something that is unexplained by the mind. Estimates suggest that more than 10 percent of people in the United States carry an irrational fear of this kind.

The problem with phobia is that while the person probably knows the reason for the fear and also that it is not warranted, it still does not go away. While the fear of heights, water and being stuck in an elevator has been described at length, we present a list of six lesser known phobias:

1. Agoraphobia is a fear of public places and a person with the disease is scared being trapped in a public place or a place like a bridge or a line at the bank. If not treated, the problem can cause the patient to become home-bound.

2. Socialphobia is something beyond shyness where a person feels extreme anxiety and fear about how they will come through at a social gathering. Their key concern is how the actions will appear to others. Untreated, these patients can retreat completely from social contact.

3. Zoophobia is not just a fear of animals and comprises a bunch of fears like ophidiophonia or a fear of snakes, to ornithophobia which is a fear of birds. Others like arachnophobia (fear of spiders and apiphobia (fear of bees) are also the result of childhood fears.

4. Brontophobia is a fear of thunder where the person refuses to step out when she hears thunder. Some even hide beneath couches or sit out a storm in the closet. This abnormal fear is shared by people and animals.

5. Aerophobia is a fear of flying. A traumatic experience involving an airplane like passing through turbulence or witnessing a crash can result in this extreme condition. The disease is usually treated via hypnotherapy.

6. Injury Phobia: The sight of blood, injection and injuries can result in this fear amongst people. Some are scared of invasive medical procedures like surgeries while others faint at the sight of blood.

7. Carcinophobia is a fear of cancer where people live with an irrational dread of the disease. Every time they feel unease in any part of the body, they start believing some malignant growth in there. So a headache can become a brain tumor and a stomach pain something to do with intestinal cancer.