7. Toy Poodle

Do not let their delicate appearance fool you; Toy Poodles share the high intelligence of their larger Standard Poodle relatives. Because of their tiny size, they are often treated purely as lap dogs and carried everywhere, which denies them the opportunity to use their active brains.

Under-stimulated Toy Poodles become easily bored, leading to neurotic behaviors and nervous yapping. Treating your Toy Poodle like a “big dog” by engaging them in scent work, obedience training, and interactive play prevents the anxiety that stems from chronic boredom.

8. Jack Russell Terrier

Jack Russell Terriers are tenacious, fearless, and driven by an intense instinct to hunt small prey. They possess a massive amount of energy packed into a small, muscular frame. When a Jack Russell does not have a physical outlet for their drive, their frustration quickly boils over into anxious, destructive behavior.

An anxious Jack Russell will dig up your garden, shred your couch cushions, and bark at every leaf that blows past the window. They require intense physical exercise—like fetch, running, or specialized earthdog trials—to burn off the adrenaline that otherwise turns into stress.