Where Do Rats Come From?
WouterThere is no clear answer to the question of where rats originate from. Some say that these critters are introduced to new areas through ships, cargo, and automobiles. Others say that they were introduced into new areas through stowing away or hitching a ride. Regardless of their source, rats have been a part of human society for thousands of years. In fact, they have been known to thrive in urban environments, including sewers and human houses.
While it is unclear where rats originated from in the past, scientists now believe they are Southeast Asian in origin. This discovery was made possible by the use of whole genome DNA sequencing of 110 wild brown rats. This DNA was then used to reconstruct an evolutionary tree. Researchers say the brown rat’s migration is likely to have coincided with rapid trade on land and sea. There are also archaeological accounts of brisk trade between these regions spanning thousands of years.
There are two main species of rats – the black rat and the brown rat. These two species are endemic to Asia. Both species are pests and are considered a nuisance to humans. They have been around for millennia, and some of the oldest Indian scriptures refer to granaries ravaged by rats. The largest species, known as the Bosavi woolly rat, was discovered in the rainforests of Papua New Guinea in 2009. It weighs around three pounds (1.5 kilograms), and is about the size of a cat. Other species, such as the Osgood’s Vietnamese rat, are smaller, ranging in length from five to seven inches (12 to 17 centimeters).
