Here are seven weird body facts, some are too strange to be true, but they are.

1. Your heart health is predicted by your earlobes—A diagonal crease in your earlobe or a lack of that crease could determine the health of your heart. Scientists are still trying to understand the link, but a study of hospital patients found that those with an earlobe crease were more likely to have coronary artery disease.

2. Yawning is contagious, but less in the summer--Seeing other people yawning, even in pictures, can make us yawn. But a 2011 study showed that yawning to photos only happened 24 percent of the time in the summer, compared to 45 percent in the winter.

Apparently, yawning cools down your brain, so outside temperature makes a big difference in how likely you are to do it. Scientists also reported that yawning helps keep us alert.

3. The body's largest organ is the size of six tennis courts, yet is only one cell thick--The endothelium is the smooth interior lining of the more than 60,000 miles of blood vessels in the body. It would cover six tennis courts if it was removed from the body and flattened. It's been called "the brain of the arteries," because it acts as a smart barrier to control which substances can pass from the blood into the arterial wall. The endothelium also makes "executive decisions" by releasing molecules that help regulate blood pressure, fight off disease, control blood clotting, and fine-tune blood so it remains fluid enough to flow easily.

4. Hearing words and seeing colors--In most people, taste, sound, and vision are separate, but there are people with a rare condition called synesthesia that blurs their sensory experiences. Some actually experience tastes in response to words, while others hear sounds when they see certain colors.

5. You can literally smell fear--People can actually detect and respond to fear by smelling people's sweat. There are different pheromones from armpit odor when people are afraid than when they aren't. Their fear can literally be picked up from their body odor.

6. The scent of women's tears reduces men's sexual arousal--A study showed that tears act as a chemical substance that's detectable by others. Men who sniffed tears found pictures of women's faces less attractive. They also reported that they were less sexually aroused.

7. Some antidepressants produce yawns—which in turn produce orgasms--Antidepressants like Prozac and Anafranil can reduce sexual arousal, but these same medications can also produce orgasm-triggering yawns in some people.