Rats are very smart animals for their size, and they will quickly adapt to changes in their environment.
For example, rats can memorize the items and location of those items in their environment, and quickly spot anything new that is put there, such as the presence of a rat trap.
For this reason, rats are known to avoid new items placed in their environment, and it may take a while for the rats to take the bait on a new rat trap.
Rats can also adapt to the food availability in their environment by using their ability to consume almost any organic material in order to survive.
Rats prefer to eat the same type of food that people do, but in the absence of conventional food, they can also ingest paper, cardboard, or many other items in order to survive.