Rats have an interesting history with humans, some good and some not so good.
Rats have a very long history. It is believed that the first group of rats, the Norvegicus Rats (Known as the brown Rats) origins go back to China and Mongolia, original call the Asia plains, where their ancestors used to live in burrows over 160 hundred thousand years ago. This group of rats revolved around the Anagalids. Some wild rats still live there today.
The rats that we are most formally with are called Rattus, they evolved around 4.5 million years ago in the Mediterranean countries. They split into two different groups around 2.5 million years ago. From there they have into over 51 different species groups
They connected with humans as our race was developing, over several thousand years ago. From this and with properly some unknown help from humans they work their way around the globe. Rats were possibly used as a source of food at that time too. I know some countries today still have rats on the menu. These are normality undeveloped countries where rats are a free source of food.
Rats got a bad reputation for being thought responsible for the Black Death plague throughout the middle ages killing millions of people, however, they may not of been responsible. See articles in national geographic – https://news.nationalgeographic.com/2018/01/rats-plague-black-death-humans-lice-health-science/. This is properly why humans do not like rats too much, and it properly not even their fault.
Using Rats to torture people in the seventeenth century would not of help their reputation either. This is where a person place on a benchon their stomach and then tie to it. Then put in the cage with the Rats and then the rats would eat the person. Not a good way to die.
Rats started to become more popular as pets around the start of the nineteenth century.
But the truth is we humans should be grateful to our Rats friends as they have helped us in a lot of different areas of research, especially in the medical research area which is still happening today. Today any rat keep for research purposes is a lot better look after than it was in years gone by. They are properly even having a better life than most rats on the street. However, this research has also been a help to the rats too. It has helped work out what is a good rat diet for them, and what rat cages are best for them. A good example of this is in the book, The China Study by T. Colin and Thomas Campbell, which refers to research done in regard to Rat’s diet. It brings up the research where rats fed on a high protein diet versus rats fed on a low protein diet. The rats fed on the high protein diets did not survive as well as the ones on the low protein diet. This was a big test study in relation to tumors and cancer research. The results from the study, are helpful to both the human race and pet rats.