Behavior and Temperament
Predicting a puppy's adult personality and temperament isn't an exact science, but the following tips will give you some grounds on which to make your decision.
Ask how the puppies have been socialized. They should have been exposed to plenty of people outside the breeder's family.
Before they reach maturity, dogs go through five stages of development: the neonatal period, when they're just born; the transitional period, starting when their eyes open; the socialization period, starting when their ears open; the juvenile period, starting at ten weeks; and puberty, starting at about six months.
Pug puppies should view all people as a source of pleasure and entertainment. While some may be more cautious than others, in general they should be curious, friendly, and trusting toward people.
To evaluate a puppy's temperament, start by looking at his parents. Are they outgoing or shy? Friendly or suspicious? Loud or quiet? Temperament is heritable. Pug puppies are with their mother constantly from birth until they go to their new homes, so she has a tremendous influence on their development. Dad's temperament plays a role as well, but it's from Mom that puppies take their cues on how to react toward people, other animals, sounds, and other sensory events. The more adult dogs you can meet at the breeder's, the better you will be able to gauge a puppy's future temperament.
Puppy Interactions and Play Styles
Watch the puppies interact as a group. Is one more dominant than the others, jumping on his littermates and taking toys from them? Or is there one that all the other puppies pick on? For most people, a pug that falls between these two extremes is a good choice. Dominant dogs want to run the show and can be difficult to train, while submissive pups may have low self-esteem, which can lead to behavior problems such as submissive urination.
Toss a toy, and see how each puppy reacts. Does he run helter-skelter after it or proceed in a more deliberate fashion? When you take the toy away, does the puppy give it up with a smile or hang on for dear life, growling through his teeth? The reaction you see gives you a clue as to future personality. Prefer the polite puppy to the growler.
Puppies and People
After you've watched the puppies for a few minutes, sit down and see if one or more will come to you. How do they behave? Are they excited to meet you or somewhat submissive? A confident pup has a wagging tail and an alert expression. Offer a treat. The puppy that trusts you enough to come forward and take the treat has good training potential. Avoid a puppy that backs away with an anxious bark. Speak softly. Which puppy cocks his head and listens to you?
Gently roll each puppy on his back. Does he squeal indignantly and struggle to get up or does he relax for a tummy rub? The squealer may become a domineering pug that wants to run the show. You'll need to give plenty of consistent training and strong leadership so this pup will know who's really in charge.
Be sure you differentiate between the pup that's merely high-spirited or assertive and one that's aggressive, fearful, or suspicious. The latter puppy may try to bite, which isn't a good sign. Pugs are known for their sweet, nonaggressive temperaments.
Walk away and see if any of the puppies follow you. Give them a little encouragement if necessary. Some puppies come readily, while their littermates need a little more time to evaluate the situation. Caution isn't a bad thing and shouldn't be confused with shyness. A nice pug with a moderate temperament will be happy to follow you without a lot of wild behavior, such as running in circles, barking, or dashing away.
Next, pick pups up one at a time and gauge their reaction to being held. Does the puppy squirm and struggle or relax happily into your arms? Does he squirm a little and then relax? Being held by a stranger is stressful for puppies, and you want to choose one that reacts to stress by calming down in a reasonable amount of time. The pup that can't control his fear or his desire to be in charge may give you problems in the future.
While you're still holding the pup, walk away from the others. Does he show alarm at being separated from his mother and littermates? Some unease is natural, but if a pug pup trusts people, he should eventually relax and enjoy the ride. You may notice that a quiet puppy becomes more animated and inquisitive on his own, while a bold one becomes a little insecure. A puppy that becomes extremely fearful probably isn't a good choice.