The greatest dog experiment ever conducted

What if I told you one of the greatest scientific studies ever conducted on dogs could probably never be repeated today?

It wasn't because the science was flawed.

Quite the opposite.

The study was so thorough, so carefully controlled, and so enormous in scope that recreating it today would require decades of funding, hundreds of purpose bred dogs, an army of dedicated researchers, and a level of institutional commitment that is difficult to imagine in our modern world.

Not to mention the ethical implications that would arise from our modern sensibilities.

Yet that is exactly what two remarkable Americans accomplished.

Most dog lovers have never heard of John Paul Scott or John L. Fuller.

I certainly hadn't before I became obsessed with dogs.

In 2018, while writing the Dire Wolf Project book, I picked up their landmark work, Genetics and the Social Behavior of the Dog.

To be honest, I expected a dry academic reference that I would simply work through for the information I needed.

Modern discussions about canine temperament are often filled with "tests" that a well trained dog could easily learn to pass, and I assumed this would be another technical volume that repeated ideas everyone already believed.

I couldn't have been more mistaken.

Within a few chapters, I realized I wasn't reading another book about dogs.

I had stepped into one of the most ambitious scientific investigations ever undertaken.

Before we walk into those kennels, though, let me introduce you to the men who built them.

John Paul Scott seemed destined for science almost from the beginning.

His father chaired the zoology department at the University of Wyoming, so conversations about animals were as common in the Scott household as discussions about the weather.

Curiosity became second nature to him.

He loved athletics every bit as much as academics, finished college in only three years, and earned a Rhodes Scholarship to Oxford University.

John Fuller reached the same destination by a very different road.

Raised in a family that prized education, his future changed unexpectedly after a serious illness during his teenage years altered his college plans.

Rather than dwelling on the disappointment, he devoted himself to genetics with the quiet patience that would eventually define his career.

One man spent his life trying to understand behavior.

The other spent his life trying to understand inheritance.

Together, they became one of the greatest scientific partnerships in canine history.

Now imagine yourself driving through the pine forests of coastal Maine on a cool morning sometime in the early 1950s.

The air carries the faint scent of salt from Frenchman Bay.

Ahead, the buildings of the Jackson Laboratory appear through the trees.

As you step from your car, dozens of eager yips greet the morning.

Adult dogs bark from orderly kennel runs while puppies tumble over one another inside nearby nursery pens, completely unaware that they are participating in an experiment unlike any the dog world had ever seen.

Nothing here happens by accident.

Every litter has a purpose.

Every observation is written down.

Every puppy is helping answer a question that breeders had debated for centuries.

Are puppies born with their personalities?

Or does experience create the dog they eventually become?

Many people have opinions about the answers to these two questions.

But, Scott and Fuller weren't interested in opinions.

They wanted evidence.

As you walk farther into the kennels, you notice shelves lined with notebooks.

Feeding schedules are carefully recorded.

Health records are meticulously maintained.

Puppies are weighed, examined, and observed according to the same schedule, week after week.

Every behavioral test is performed at precisely the same stage of development so that one puppy can be fairly compared with another.

The meticulous order established in this place is almost mesmerizing.

Then, you arrive at the nursery.

A new litter has just been born.

Some of the puppies remain with the mother that brought them into the world.

Others are gently lifted, carried to another nursing female from an entirely different breed, and placed beside their foster siblings.

At first, the scene feels almost unbelievable.

Why would anyone do that?

Because Scott and Fuller understood something every good scientist knows.

If they wanted to discover whether temperament was inherited, they first had to eliminate every reasonable alternative explanation, such as the possibility that differences in behavior were simply the result of how each puppy was raised, handled, or influenced by its mother rather than something written into its genes.

Months later, those same puppies would be tested in identical ways.

Some would approach unfamiliar people with confidence.

Others would hesitate.

Some solved simple problems almost immediately.

Others persisted patiently until they found the answer.

Some matured more quickly than others.

Nothing was dismissed as coincidence.

Every difference became another clue.

Year after year... litter after litter... generation after generation... the experiment continued.

Eventually, carefully planned crosses were added to the colony, allowing the researchers to watch inherited traits emerge in new combinations.

Twenty years passed before the work finally drew to a close.

The result was far more than another scientific publication.

It became one of the strongest foundations ever laid for understanding canine temperament.

Scott and Fuller demonstrated that genetics influences much more than coat color, ear shape, or body size.

Sociability, emotional reactivity, persistence, problem solving, and even the pace at which puppies develop all showed inherited patterns, while experience continued shaping how those inherited tendencies unfolded throughout life.

One discovery, in particular, transformed puppy raising forever.

Young dogs pass through critical periods of development when certain experiences leave lasting impressions.

Miss those windows, and some lessons become much harder to teach later.

Today, breeders and trainers around the world benefit from that discovery, whether they realize it or not.

As I turned page after page, I found myself admiring something beyond their conclusions.

I admired the way they thought.

Whenever a question formed in my own mind, I would keep reading only to discover they had already designed an experiment to address it.

They anticipated objections before critics could raise them.

And they refused to settle for easy answers when better evidence could be found.

Only once in their 500 pages of research did I catch myself wishing they had gone a step further.

Shortly after birth, each newborn puppy was briefly placed on a scale.

The assistants noticed that some puppies struggled energetically while others remained surprisingly calm.

They mentioned those observations in passing, but never formally recorded them because no one yet imagined those first moments of life might contain meaningful behavioral clues.

That tiny omission didn't lessen my admiration for the incredible attention to detail Scott and Fuller achieved, though.

If anything, it reminded me that every generation of scientists stands on the shoulders of those who came before.

As America celebrates its 250th birthday, I find something deeply inspiring in the legacy of John Paul Scott and John L. Fuller.

While others chased discovery across distant landscapes or into the skies above, these two Americans turned their attention to a quieter, less celebrated frontier.

They devoted twenty years to one of the oldest mysteries in the relationship between humans and dogs.

And they pursued that mystery with remarkable patience, humility, and scientific integrity.

Every time I formally evaluate the temperament of an American Dirus™ puppy, I owe a quiet debt of gratitude to two scientists whose names deserve to be remembered.

They didn't simply study dogs.

They gave generations of breeders a stronger foundation upon which to understand them.

I like to think I'm carrying forward a remarkable American legacy of curiosity, careful observation, and scientific integrity.

If you'd like to read the book I wrote that includes Scott and Fuller's extraordinary work and many of the scientific studies that shaped the American Dirus™ breeding program:

Dire Wolf Project: Creating an Extraordinary Dog Breed.

It's the very book that details the way Dire Wolf Project™ breeders think about canine genetics, inherited temperament, and what responsible dog breeding can become.

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P.S. The next time you read one of my temperament evaluations for an American Dirus™ puppy, remember that you're seeing far more than a personality description.

Every observation rests upon generations of breeders, behaviorists, and scientists who patiently worked to understand how puppies develop.

I often think back to those kennels in Bar Harbor, where John Paul Scott and John Fuller patiently recorded thousands upon thousands of observations, determined to understand what made each puppy unique.

Their work forever changed the way thoughtful breeders evaluate temperament.

And every time I sit down with one of our own puppies and begin taking notes, I feel connected to that remarkable American legacy of curiosity, careful observation, and scientific integrity.

Jennifer Stoeckl is the co-founder of the Dire Wolf Project, founder of the DireWolf Guardians American Dirus Dog Training Program, and owner/operator of DireWolf Dogs of Vallecito. She lives in the beautiful inland northwest among the Ponderosa pine forests with her pack of American Dirus dogs.