If I see a cat before my dog does I’ll try to chase it off before the dog sees it and I don’t want my dog killing cats but there is little I could do to prevent it if my dog caught one.
Jack Russells kill instantly with a neck snap. They’re rodent killers and its in their nature. I’ve often said that if a Jack Russell grew as large as a pit bull they would be a dangerous dog but they seldom grow larger than 15 lbs or so. My vet actually said she would like to see me breed mine for his exceptionally mild temper with people.
It would be different if he were raised with a cat but the instinct is just too strong now.
Good doggie! :)