Bed bugs originated in the tropics and have been annoying people for a very long time. They were first documented during the first century, and they are noted for their ability to hitchhike on people's clothes or other sources of fabric. Bed bugs have likely been a problem for humans since day one, but there are several reasons as to why they are becoming a big problem now. Mass transit and international travel have made bed bugs a problem for everyone in the world. A bed bug can go an entire year without eating so they can survive international travel despite not having any source of food during the trip. A lesser known reason that explains why bed bugs in particular are able to multiply so quickly is incest. It has been noted that bed bug infestations can begin with individual bed bugs indicating that bed bugs interbreed. Most insects cannot survive close interbreeding for the same reasons that humans cannot. For most insects interbreeding would result in genetic disaster, but like cockroaches, bed bugs interbreed constantly and experience no genetic difficulties. Where is a bed bugs natural habitat? Is it indoors? How did they survive before humans lived in homes?