I might be wrong, but in my mind aggression and anxiety can be aspects of the same thing. Sort of like when certain people or pets are hungry, they begin to act angry — hangry is a term I’ve heard for it, though I don’t know if it’s in the dictionary…. I’ve even seen this concept used in ads to sell candy bars, which only serves to convince me that anxiety (IMHO, hunger is a type of this) can create aggression.
Regardless of whether you agree or not, here are 2 interesting infographics – one on anxiety in pets and the other on the ‘ladder of aggression’. BTW, I thought it was interesting that the anxiety chart did not include hunger.