Same as they do in a house or office
RATS
sewers
You can buy cheep fuzzy rats in the sewers
Actually, the sewer people mate with rats to make Ratmen, who then live in the sewers. So, there is more ratmen.
Because there's garbage, water, shelter, and safety in sewers. What more could they want?
You can find these Hell Rats in the sewers in Varrock, You can find Varrock by exploring your map, have fun.
rats, garbage, poop
The cell theory states that all living organisms are composed of cells, and that cells arise from pre-existing cells. This principle explains why rats do not spontaneously originate from sewers; instead, they reproduce from existing rat populations. The presence of rats in sewers is due to their migration and not a result of spontaneous generation from non-living matter.
You can often find rats living in sewers, but that's not the only place they live. They can also live on the streets, especially dirty areas, in the country, in homes.. basically anywhere. Eww..
Giant rats can commonly be found in sewers and drainage systems throughout the city. These are common homes for them as they are secluded from humans.
Garbage dumps, sewers and anywhere they can find shelter away from the eyes of people and other predators.
The Bubonic Plague otherwise known as black dealth was originally spread by a type of insect I believe similar to a mosquito. In Asia, around India, has a huge collection of rats and the disease was passed to the rats. Rats then got in sewers and other commonly used places by Europeans and so they got the plague