wild rats

Question
im doing some work at college and need to know the wild rats original origin? and wounderd if you could help me?

Answer
Hello,

True rodents are thought to have originated in Asia. Rodents first appear in the fossil record about 54 million years ago. These original rodents were themselves descended from rodent-like ancestors called anagalids, rabbits are closely related to this group. Murids are the distant relatives of the present day Norway rat as well as other rodents like gerbils, they first appeared about 34 million years ago. The genus Rattus (this is how different species of rats are classified) was formed about 3 million years ago and it was native to the Mediterranean countries, the Middle East, India, China, Japan, and Southeast Asia (including the Philipines, New Guinea and Australia). Now a days there are 51 species within the genus Rattus. Both the Norway rat (Rattus norvegicus) and the black rat (R. rattus) came from Asia originally. Norway rats were probably from the area that is now China and Mongolia and black rats were found further south. Today there are rats in most countries of the world. Both species of rats travelled to Europe with humans or Norway rats may have crossed the river Volga from southern Russia after 1727 in an enormous migration and colonized Western Europe from there. There is not a lot of evidence to support these theories because it was not always documented very well. Norway rats spread beyond Europe and Black rats reached the New World in the 16th century. Norway rats reached North America around 1755 on the ships of the new settlers and were reported on the east coast of the United States in 1775 reported in Jackson 1982.
Norway rats have almost completely replaced black rats in Europe and America, where black rats are now rare or absent in much of their former range. In contrast, in tropical zones black rats are more common than Norway rats there.

I hope that this helps you and good luck with the college work. If you have any more questions then feel free to ask.