One of the main things rats are unable to do it throw up. They cannot vomit or burp or anything like that as their digestive system is different to ours.
The poison (most likely arsenic) in the rat killer poisons the rat, therefore killing the rat because of the poison. The actual effect of most rat poisons on a rat is to cause the animal's body to...
There is no such thing as a "pack rat." It is a sterio type given to rats because of there burrowing nature. but roof rats and norways can mate.
Pack rats do, indeed, exist (see link) but they are...