Border Collie

They consistently top rankings of working and obedience intelligence, including the well-known list compiled by psychologist Stanley Coren. In practical terms, that means they learn quickly and solve problems, not that they are easier to own. A clever dog that is bored will learn to open doors, raid bins and train you to throw the ball on demand, so intelligence adds to the owner's workload.

It can, but only with a committed owner. City collies often struggle with traffic, crowds and constant movement that sets off their herding instincts. Those that thrive usually have owners who drive to open space every day, take part in a sport such as agility, and train calm behavior around bikes and buses. A small flat with long workdays and short walks is a poor match.

That fixed stare, often with a lowered head and a crouch, is the 'eye' used to control sheep. Other dogs can read it as a challenge, which may start arguments at the park. Interrupt the stare early by calling your dog away and rewarding it for looking at you, and give it plenty of space from dogs that react badly to being watched.

Working lines are bred for herding and tend to be lighter, more intense and more driven, with more variety in coat and ear carriage. Show lines are bred to a written standard and are often more heavily coated and uniform in appearance, sometimes with a calmer temperament. Both need plenty of mental exercise, but a working-line puppy usually needs even more.

Most are not constant barkers, but many bark at movement, during play, or when frustrated. Some become very vocal at agility or while watching another dog work. Excess barking is usually a sign of arousal or boredom. Build daily quiet time into the routine, reward calm behavior, and avoid games that wind the dog up with no clear end point.