Despite the lack of conclusive evidence, it is thought that bed bugs like to bite people of certain blood types rather than others. Some blood types are thought to emit more heat than others. Since bed bugs are drawn to water, people with warm blood, also known as "blood type O," are more likely to be bitten. However, a number of factors, such as alcohol, exercise, sickness, and feelings, may all contribute to a rise in body temperature. According to certain reports, bed bugs avoid blood that has been tainted with alcohol. Another hypothesis is that bed bugs prefer the blood type in which they grew up. If they eat AB blood type as a child, they will most likely eat AB blood type as an adult. This isn't to say that if the AB blood type isn't available, they won't feed on other blood types. They will eat every kind of blood.