Ticks have been long known to transmit Lyme disease. However, there are more than 800 species of tick, and only two of these carry disease to humans at all! That doesn't stop tick bites from being a great annoyance, especially considering they're caused by a tick sucking your blood! Often grouped with another real-life vampire, the flea, ticks use this blood to complete their life cycle while fleas use it for food. Surprising facts about the life...