Bed bugs have been sucking blood for as long as humans have existed, probably even longer. Ever since humans learned the comforts of caves, these parasites branched off from their original bat hosts and learned that human blood is sweeter. The fossilized remains of bed bugs ancestor were uncovered and they traced some 11,000 years ago.

Scientifically known as Cimex lectularius or Cimex hemipterus, researchers agree that they may have branched from evolutionary blood sucking bed bugs from 98,000 years ago. They evolved to their modern version between 5,000 to 11,000 years ago. The oldest known fossil prior to recent discovery was discovered in Egypt and was dated at 3,500 years ago.

Arguably, the oldest ancestor of bed bugs is the Quasicimex eilapinastes which shared the same DNA to modern-day suckers. However, it is difficult to accurately link the two insects since no same bed bug survived today. At any rate, they share the genus from the Cimex family.

Since humans and bats lived in perfect harmony in the ancient caves in Oregon, bed bugs eventually branched to suck on humans. What puzzles the scientists is why the bed bugs decided that they are content with human hosts. They apparently never branched out to form another Cimex genus that feeds on other species. Popular Science noted the researchers' observation that cohabitation and probably the limited number of hosts retarded further infestation.

Bed bugs are known to have sucked blood from other hosts like chickens and domesticated animals, according to a study published at the University of Florida. However, they still prefer humans whenever possible. Imagine the sheer number of these insects if they are flexible to feed on several hosts.

Meanwhile, the development of modern insecticides has significantly reduced the number of bed bugs. There is a resurgence of infestation in 1995 but it has long been addressed by pests control experts. Further, the bed bugs' nature of living in confined spaces makes copulation difficult.