In many parts of the world, including the UK, eating rats as a food source is considered taboo. However, according to Wikipedia, it is a staple of the diet in many countries. The risk of spreading disease is often cited as the reason for many people having an aversion to eating rats.
Some cultures have limited the consumption of rats as a food source to particular social and economic classes. In the Mishmi culture in India, rats are essential in women's diets. This is because Mishmi women are only permitted to eat fish, wild birds, pork and rat meat.
The Musahar group in northern India farm rats as an exotic delicacy. The traditions of the Polynesians and Hawaiians allow the general population to eat rat as a daily food. During feasts the Rapa Nui Polynesians ate rat meat, although their king was denied this. This was due to their belief of his sacred state.
In West Virginia in the United States rat stew is often eaten. In Victorian Britain and France the well off ate rat pie . The Vietnamese are famous for eating rat meat.
In the south-east Asia bandicoot rats are an important source of food. The United Nations food and agriculture organisation have calculated that rat's meat is half the meat produced locally in Ghana. Cane rats are hunted and farmed in this area for their meat. The aborigines of Australia often eats rats.
In most other parts of the world eating rats is considered to be disgusting.