If an animal kills someone should they be held responsible?

If an animal attacks like say a big dog attacks someone should it not be the animal that is charged and not the owner? Because we all know that dogs know what they are doing, they choose to attack things so should they have to pay the penalty for their actions? If so what sort of sentencing should be used for animals should they get the same time as humans or should it be scalled down so its the same number of years in dog years? I know I sound like I am targetting dogs alone but if any anmial commits a criminal offence the full force of the law must be brought to bear on them.