Answer to Question 1
Drilling is a sound made by the molar teeth. This vocalization occurs when the guinea pig is in pain or is very frightened. It also is used by boars to ward off other males in pursuit of a sow.
Answer to Question 2
The tattoos are placed by a company called Marshall Farms to indicate that that the ferret has been spayed or neutered and de-scented and has received an initial distemper vaccination.