Rats introduce a necessary upkeep mechanism to your ship.
Simply put, when you start on a brand new ship overtime it will spawn rats.
At first they are not a problem and seeing one or two scurrying and then running and hiding under barrels isnt an issue.
However leave them for a while and you have an infestation.
If left unchecked, food items in your barrels will go missing as they presumably get eaten.
Cooked food items stored in barrels will also spoil causing you to vomit as you eat. It will also negate the health regen.
((Basically spoiled food is like turning a cooked food item back to raw..except you cannot cook spoiled food further))
To maintain proper ship hygiene you must kill rats and keep on top of them.
Rats will only show for a period of time before they burrow under and behind barrels so you must strike them when they show.
However if you are too impatient to wait for the rats to come out of hiding you can always flood your deck causing the rats to float and swim around. Or you can also set the deck on fire!
There is no way to stop rats spawning but you can cull them and have a rat free ship by occasionally keeping on top of the population.
RAT SHOT
You can also capture rats by interacting and load them into a cannon to fire and infest other ships too.
You can go a long time before you get a rat on your ship but the longer you are sailing around the more chance you have of getting a single rat spawn.
Ships with high amounts of stored food will also have a higher spawn chance.
Keeping low food stocks you likely will hardly see a rat ever.
