Rats are rodents that have been around for millions of years. Rats live all over the world, thanks to the fact they traveled on boats to every country. They eat about anything, which means they will live anywhere where there’s food, including in sewers.

Human leftovers make great food sources for rats who don’t have to work hard to procure their food. Being largely nocturnal, rats will eat your food while you sleep. They are surprisingly quiet and can go for quite a while undetected.

So Why Sewers?

When waste was just dumped in the streets since the beginning of towns, rats were attracted to the easy food. They never really left, preferring to eat what we dumped freely. Thus, when sewer systems began to be developed, rats just followed the food — underground. Here, their environment was perfect for living. They were protected and had great shelter, and their food came to them still. Rats can’t see very well, which is fine in the dark. However, they have great sense perception with their whiskers, and they can smell food exceedingly well. Rats have great taste buds, which is how they can detect poison in food and not eat it. They hear very well. Sewers were natural places to call home to the rat.

Will Rats Always Live in Sewers?

The answer is yes. Rats reproduce incredibly quickly, with some species having up to 2,000 babies in one year. Thus, it would be impossible to kill off all rats. Besides, they do a dirty job for us that we don’t want to do, which is clean up any food and waste in our sewer systems. While rats do carry a variety of nasty diseases, including hantavirus, leptospirosis, lymphocytic choriomeningitis (LCMV), Tularemia, and Salmonella that are harmful to humans, they don’t seek out humans. In fact, they avoid us like the plague, which should make you feel a little better. Do be careful because the stories about rats coming up out of your toilet are true. Luckily, this doesn’t happen very often.