When animal lovers even think about puppies, most can feel themselves getting softer. For some that may mean smiling. For others, the thought may elicit memories of puppies past or present with whom they shared their lives or encountered over the years.

Although they may love adult dogs very much, most agree there was something special about those babies. Even people who normally ignore dogs often will admit that they find most puppies appealing.

Nor are veterinarians and their staffs immune to phenomenon. Bring a puppy into the treatment room, let alone hospitalize one, and the whole team will notice. Staff members who normally assume a calm and confident manner with adult animals may begin cooing and babbling submissively.

But obviously, evolution didn’t result in young animals whose looks appealed to humans. Or did it? Yes and no.

Mammalian as well as the young of multiple species of wild animals look more appealing to many humans, even though those same animals will have no contact with humans under normal circumstances.

However, if viewed in terms of anatomy and ethology, the reason for those appealing looks becomes clear. Those compressed faces facilitate passage through the birth canal and nursing. And if young were born looking and acting like adults, i.e., potential competitors or predators, this would reduce the amount of parental care adults would want to invest in them.

Domestication prolongs these effects via the process of neoteny. Among domestic animals, companion dogs may form the most intimate bonds with humans because they’ve lived with us the longest.

This raises an interesting point regarding purebred companion animals: did and do some breeders deliberately breed dogs for more exaggerated infantile features? And if they do, does this reflect changing human perception of how we want these animals to look, i.e., less threatening?

Traditionally, persistent infantile features were associated with toy breeds, e.g. Pekingese, Shih Tzu, King Charles spaniel. But today, such features increasingly appear in larger breeds, too.

Compare the more "block-headed" Labrador and golden retrievers with their shorter muzzles and more prominent eyes and ears to the more mature features of the breeds’ working ancestors. Or the softening and more infantile features of the border collie since the breed gained AKC show recognition.

Nor is this phenomenon limited to purebred dogs. Many lines of designer poodle mixes, e.g. goldendoodles and schnoodles, possess this same look. Then we have the extreme versions of brachiocephalic dogs, described by their admirers as "smooshy little baby faces."

These extremes and their attendant medical problems remind us yet again that we can’t change animals’ looks without changing their physiology, behavior, and bonds with people.

Meanwhile, we have a training approach that places all puppies into puppy kindergarten at 8-10 weeks of age that assumes all puppies develop at the same rate. However, doing so may undermine the success of some animals.

One-size-fits-all classes often disregard how much young animals can and need to learn alone. This includes exploring a secure space on their own, making up games, and otherwise amusing themselves.

The saying "the more they need to learn, the more they need to play" sums up all the lessons young animals teach themselves. These lessons include how to move through space, the strengths and limits of their anatomy and physiology, the physics and mathematics of intersection and avoidance, resiliency, a sense of self and self-control. Plus, all the self-confidence that comes from discovering and mastering all these skills.

Puppies with exaggerated infantile features, in particular, may face two opposite human-related problems. Some people can’t wait to expose their adorable new puppy to as many people and novel experiences as possible and bask in the attention it gains them as well as their animals.

Those in another group perceive their puppies as fragile and hover and attempt to control everything the animal does. The lack of the previously described self-skills may undermine the behavioral development of animals in both groups. Some puppies may become overstimulated and excessively attention-seeking, while others may become timid and neophobic.

Puppy kindergarten as soon as possible may be recommended to address the problems in both groups of young animals. This is a viable approach — provided puppies with the same temperament and behavioral challenges attended classes with other puppies having the same orientation.

However, if no pre-class screening process exists to identifying these animals, high-energy, easily over-stimulated puppies may wind up in the same class as more timid ones. Although this may work some or even most of the time, the nature of my practice is such that I hear about it when it doesn’t.

When class-related problems arise, these more likely occur when classes end with free-for-all puppy play periods instead of calming ones. During these, puppies lacking self-control often play too rough and gain reputations as bullies.

At best, they’ll be separated or banished. This will anger or humiliate their owners who then vow never to subject themselves and their animals to that again.

Meanwhile, one negative interaction with one of those more unruly pups sends more timid animals under their owner’s chairs. Owners who experience what they describe as “puppy brawls” instead of the puppy play time they envisioned at the end of the class also may vow never to subject their puppies to classes again.

Both kinds of puppies would have benefited from a puppy class that addressed their respective temperaments and the bond effects related to these once they learned those basic self-skills at home. Barring this, the classes did more harm than good to all concerned.

But regardless of how much people may want to perceive their puppies as babies, canine behaviors can and do change as dogs mature. In human-companion animal households with plentiful resources, people who want to continue perceiving their older dogs as puppies may resist addressing problem behaviors if any treatment involves recognizing this.

For example, because Mary took a more casual, he’s-just-a-baby house training approach with her French bulldog puppy, she doesn’t notice when he transitions from elimination behavior to marking as he gets older. To her, pee is pee and where it occurs means nothing.

Or rather, it didn’t until he started marking her bed. Not only did he lift his adorable little leg on all four corners of her bedframe, he liberally marked the head board, too. Nor did she find the (un)conventional "everyone knows little dogs can’t be house-trained" baby-dog wisdom that excused the behavior comforting.

The effects of domestication, deliberate breeding for enhanced infantile canine facial features, and the delayed development in some of these animals all may contribute to behavioral problems as these puppies mature.

Perceiving puppies as unique physiological-behavior-bond bundles from first contact and addressing all three components simultaneously from the beginning can prevent problems as the animals mature.