Beagle vs Jack Russell Terrier

A Beagle's nose runs the dog, not the owner — bred to follow a scent trail for miles regardless of what the handler wants, so unreliable off-leash recall is a breed trait, not a training failure, and a bored, under-exercised Beagle is one of the most vocal and destructive small breeds there is.

Jack Russells are working hunting terriers bred to chase prey underground, and breed sources are blunt that this drive cannot be trained out — a JRT will typically see the family cat or a hamster as prey — and the breed's stamina, digging, and escape-artist tendencies routinely surprise owners who pictured a small, easy lapdog.