6 reasons dogs truly are man’s best friend

Research suggests dog ownership may improve heart health, decrease depression, and even help you live longer.

6 reasons dogs truly are man’s best friend
  • Dogs have been man's best friend for at least the past 15,000 years.
  • Science now shows that this symbiotic relationship has been as beneficial for humans as their canine companions.
  • Benefits of dog ownership include familial ties, a reduce risk of schizophrenia, and improved cardiovascular health.


Under cover of darkness, a pack of ancient wolves slowly stalk the camps of our nomadic ancestors. But they are not on the prowl. These timid, congenial Canidaes have discovered they can scavenge human kills and midden piles for more reward, and far less risk, than the hunt.

Over successive generations, their offspring grow more docile and more dependent on their human benefactors. In time humans adopt these four-legged moochers, taking them into their service with the tacit agreement of better food and companionship. And so, the human-dog relationship was born.

That's one possibility at least. All that's generally agreed upon is that dogs became man's best friend as early as 15,000 years ago — though some fossil evidence suggests domestication as far back as 30,000 years. As science writer James Gorman points out, this means we loved our tail-wagging besties before inventing agriculture, language, or permanent homes and even before we domesticated cows, goats, and, of course, cats.

"As we became friends with them, they became friends with us, and we have a dependency that's charming," Bill Nye, science guy and lover of all good dogs, told us in a 2015 interview. "It's enriched both the dog lives and the human lives."

For humans, the perks of the dog-human relationship run much deeper than games of fetch or a handy excuse to go for a nice, long walk.

Dogs see us as family

Dogs see their people as family, and the feeling seems to be mutual.

(Photo: PxHere)

It's not our imaginations or a poetic attempt to explain behavior through personification. Dogs do view their people as family.

Cognition scientists at Emory University placed dogs in an MRI machine and scanned their brains while presenting them with different odors. Some aromas were of food. Others were from other dogs. And some were from the dogs' human companions. The dogs' brains' reward centers lit up most when presented with the human scents, showing they prioritized human relationships.

These results bolstered other research that shows dogs act similarly to human sounds and that they are the only non-primates to run toward humans for protection and comfort.

Dogs reduce the risk of schizophrenia

A little girl meets Lothair and Molly, two certified therapy dogs, at U.S. Air Force Base Hospital Langley.

(Photo: Brittany Paerschke-O'Brain/U.S. Air Force)

Dogs may be able to curb the risk of some mental diseases. That's the conclusion of research published in the peer-reviewed journal PLoS ONE, which found a link between dog ownership and a reduced risk of schizophrenia.

The researchers looked at 1,371 men and women across the socioeconomic spectrum. Roughly 400 participants suffered from schizophrenia, another 400 from bipolar disorder, and about 600 were controls. After a survey in which the participants were asked about pets, the researchers compared ownership with rates of mental illness.

They discovered that dog ownership before the age of 13 correlated with a 25 percent reduced risk of schizophrenia. Participants who owned dogs in the first years of life showed the largest protective effect.

"There are several plausible explanations for this possible 'protective' effect from contact with dogs," lead author Robert Yolken said in a statement. "Perhaps something in the canine microbiome that gets passed to humans and bolsters the immune system against or subdues a genetic predisposition to schizophrenia."

Sorry, ailurophiles. Cats did not show a similar link between ownership and a reduced risk of mental diseases.

Dogs are your heart's best friend, too

Regular walks with your dog is great exercise and boosts cardiovascular health.

(Photo: PxHere)

The health benefits aren't just in the mind. Preliminary research published in Mayo Clinic Proceedings: Innovations, Quality & Outcomes suggests that pet ownership boosts heart health, especially if that pet is a dog.

Researchers evaluated roughly 1,800 participants using the American Heart Association's Life's Simple 7, seven life factors that people can improve to help achieve cardiovascular well-being. They then compared the health of pet owners with those who did not own pets and found a correlation between dog ownership and heart health. The researchers associated this salubrious effect with increased engagement and physical activity.

"In general, people who owned any pet were more likely to report more physical activity, better diet and blood sugar at an ideal level," Andrea Maugeri, a researcher with the International Clinical Research Center at St. Anne's University Hospital in Brno, said in a statement. "The greatest benefits from having a pet were for those who owned a dog, independent of their age, sex and education level."

Follow-up evaluations are scheduled until 2030.

Dogs make life better (and longer)

An older gentleman sits with his canine companion.

(Photo: Pxfuel)

Better heart health means a better chance to live longer. That's according to a recent study and meta-analysis published in Circulation: Cardiovascular Quality and Outcomes.

The research found that dog owners who survived a heart attack were at a 33 percent reduced risk of early death compared to non-dog survivors. The same held true for stroke survivors (27 percent). Better still, dog ownership correlated with a 24 percent reduced risk of all-cause mortality, likely explained by an increase in physical activity and a decrease in depression and loneliness.

A study published in Scientific Reports corroborates a canine's life-giving, heart-healthy impact. The researchers reviewed the national registries for more than 3.4 million Swedes with no cardiovascular disease before 2001. Looking at the association between dog ownership and cardiovascular health, they found that single dog owners had a lowered risk of death, either due to cardiovascular disease (11 percent) or other causes (33 percent).

In a statement, lead junior author Mwenya Mubanga noted, "A very interesting finding in our study was that dog ownership was especially prominent as a protective factor in persons living alone, which is a group reported previously to be at higher risk of cardiovascular disease and death than those living in a multi-person household. Perhaps a dog may stand in as an important family member in the single households."

Dogs teach us ways to learn

Put simply, dogs are better at ignoring bad advice than their human peers. Research out of Yale University's Canine Cognition Center tasked dogs with retrieving treats from a puzzle. The researchers presented the steps to solve the puzzle but included many extraneous steps in the demonstration. When it was the dogs' turn, they nimbly skipped the unnecessary steps, thereby showing their ability to filter information effectively.

How did human children perform? Not so great. The children settled on pure imitation, regardless of whether a step proved useful in solving the puzzle.

"This tells us something really important about how humans learn relative to other animals," Big Think author Arpan Bhattacharyya wrote on the study. "We're really trusting of the information that we get from other individuals – even more trusting than dogs are.

"And what this means is we have to be really careful about the kinds of information we present ourselves with. We're not going to have the right filter for bad information, so we should stick to looking at information that's going to be positive, information that's going to be good."

Dogs teach us about ourselves

Dogs really do resemble their owners.

(Photo: PxHere)

Dogs resemble their owners in more ways than floppy jowls or a perky gait. Dogs mirror their owners' personalities, and owners can use this information to better understand themselves.

Research published in the Journal of Research in Personality surveyed more than 1,600 dog owners, representing about 50 different breeds. They found that dog owners shaped their dogs' personalities. Extroverted owners rated their dogs as more active and playful, while the owners of more fearful dogs tended to exhibit more negative emotions. Similarly, more agreeable owners were guardians of less aggressive pets.

"We expected the dogs' personalities to be fairly stable because they don't have wild lifestyle changes humans do, but they actually change a lot. We uncovered similarities to their owners, the optimal time for training and even a time in their lives that they can get more aggressive toward other animals," lead author William Chopik said in a release.

Another study in Scientific Reports showed similar findings regarding stress. The researchers took hair and fur samples from owners and their dogs to measure both for the stress hormone cortisol. They found a correlation in long-term stress between the two.

More than simply good dogs

These are six ways that science has discovered dogs aid their interspecies partner. As genetic research advances, dogs may prove they are man's best friends in unforeseen ways. Scientists studying the canine genome have found a number of canine disorders that closely resemble those found in humans, including some cancers. Further study may provide a wealth of information that could help us solve our own genetic mysteries.

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U.S. Navy ships

Credit: Getty Images
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Meet Dr. Jennifer Doudna: she's leading the biotech revolution

She helped create CRISPR, a gene-editing technology that is changing the way we treat genetic diseases and even how we produce food.

Courtesy of Jennifer Doudna
Technology & Innovation

This article was originally published on our sister site, Freethink.

Last year, Jennifer Doudna and Emmanuelle Charpentier became the first all-woman team to win the Nobel Prize in Chemistry for their work developing CRISPR-Cas9, the gene-editing technology. The technology was invented in 2012 — and nine years later, it's truly revolutionizing how we treat genetic diseases and even how we produce food.

CRISPR allows scientists to alter DNA by using proteins that are naturally found in bacteria. They use these proteins, called Cas9, to naturally fend off viruses, destroying the virus' DNA and cutting it out of their genes. CRISPR allows scientists to co-opt this function, redirecting the proteins toward disease-causing mutations in our DNA.

So far, gene-editing technology is showing promise in treating sickle cell disease and genetic blindness — and it could eventually be used to treat all sorts of genetic diseases, from cancer to Huntington's Disease.

The biotech revolution is just getting started — and CRISPR is leading the charge. We talked with Doudna about what we can expect from genetic engineering in the future.

This interview has been lightly edited and condensed for clarity.

Freethink: You've said that your journey to becoming a scientist had humble beginnings — in your teenage bedroom when you discovered The Double Helix by Jim Watson. Back then, there weren't a lot of women scientists — what was your breakthrough moment in realizing you could pursue this as a career?

Dr. Jennifer Doudna: There is a moment that I often think back to from high school in Hilo, Hawaii, when I first heard the word "biochemistry." A researcher from the UH Cancer Center on Oahu came and gave a talk on her work studying cancer cells.

I didn't understand much of her talk, but it still made a huge impact on me. You didn't see professional women scientists in popular culture at the time, and it really opened my eyes to new possibilities. She was very impressive.

I remember thinking right then that I wanted to do what she does, and that's what set me off on the journey that became my career in science.

CRISPR 101: Curing Sickle Cell, Growing Organs, Mosquito Makeovers | Jennifer Doudna | Big Think www.youtube.com

Freethink: The term "CRISPR" is everywhere in the media these days but it's a really complicated tool to describe. What is the one thing that you wish people understood about CRISPR that they usually get wrong?

Dr. Jennifer Doudna: People should know that CRISPR technology has revolutionized scientific research and will make a positive difference to their lives.

Researchers are gaining incredible new understanding of the nature of disease, evolution, and are developing CRISPR-based strategies to tackle our greatest health, food, and sustainability challenges.

Freethink: You previously wrote in Wired that this year, 2021, is going to be a big year for CRISPR. What exciting new developments should we be on the lookout for?

Dr. Jennifer Doudna: Before the COVID-19 pandemic, there were multiple teams around the world, including my lab and colleagues at the Innovative Genomics Institute, working on developing CRISPR-based diagnostics.

"Traits that we could select for using traditional breeding methods, that might take decades, we can now engineer precisely in a much shorter time."
DR. JENNIFER DOUDNA

When the pandemic hit, we pivoted our work to focus these tools on SARS-CoV-2. The benefit of these new diagnostics is that they're fast, cheap, can be done anywhere without the need for a lab, and they can be quickly modified to detect different pathogens. I'm excited about the future of diagnostics, and not just for pandemics.

We'll also be seeing more CRISPR applications in agriculture to help combat hunger, reduce the need for toxic pesticides and fertilizers, fight plant diseases and help crops adapt to a changing climate.

Traits that we could select for using traditional breeding methods, that might take decades, we can now engineer precisely in a much shorter time.

Freethink: Curing genetic diseases isn't a pipedream anymore, but there are still some hurdles to cross before we're able to say for certain that we can do this. What are those hurdles and how close do you think we are to crossing them?

Dr. Jennifer Doudna: There are people today, like Victoria Gray, who have been successfully treated for sickle cell disease. This is just the tip of the iceberg.

There are absolutely still many hurdles. We don't currently have ways to deliver genome-editing enzymes to all types of tissues, but delivery is a hot area of research for this very reason.

We also need to continue improving on the first wave of CRISPR therapies, as well as making them more affordable and accessible.

Freethink: Another big challenge is making this technology widely available to everyone and not just the really wealthy. You've previously said that this challenge starts with the scientists.

Dr. Jennifer Doudna: A sickle cell disease cure that is 100 percent effective but can't be accessed by most of the people in need is not really a full cure.

This is one of the insights that led me to found the Innovative Genomics Institute back in 2014. It's not enough to develop a therapy, prove that it works, and move on. You have to develop a therapy that actually meets the real-world need.

Too often, scientists don't fully incorporate issues of equity and accessibility into their research, and the incentives of the pharmaceutical industry tend to run in the opposite direction. If the world needs affordable therapy, you have to work toward that goal from the beginning.

Freethink: You've expressed some concern about the ethics of using CRISPR. Do you think there is a meaningful difference between enhancing human abilities — for example, using gene therapy to become stronger or more intelligent — versus correcting deficiencies, like Type 1 diabetes or Huntington's?

Dr. Jennifer Doudna: There is a meaningful distinction between enhancement and treatment, but that doesn't mean that the line is always clear. It isn't.

There's always a gray area when it comes to complex ethical issues like this, and our thinking on this is undoubtedly going to evolve over time.

What we need is to find an appropriate balance between preventing misuse and promoting beneficial innovation.

Freethink: What if it turns out that being physically stronger helps you live a longer life — if that's the case, are there some ways of improving health that we should simply rule out?

Dr. Jennifer Doudna: The concept of improving the "healthspan" of individuals is an area of considerable interest. Eliminating neurodegenerative disease will not only massively reduce suffering around the world, but it will also meaningfully increase the healthy years for millions of individuals.

"There is a meaningful distinction between enhancement and treatment, but that doesn't mean that the line is always clear. It isn't."
DR. JENNIFER DOUDNA

There will also be knock-on effects, such as increased economic output, but also increased impact on the planet.

When you think about increasing lifespans just so certain people can live longer, then not only do those knock-on effects become more central, you also have to ask who is benefiting and who isn't? Is it possible to develop this technology so the benefits are shared equitably? Is it environmentally sustainable to go down this road?

Freethink: Where do you see it going from here?

Dr. Jennifer Doudna: The bio revolution will allow us to create breakthroughs in treating not just a few but whole classes of previously unaddressed genetic diseases.

We're also likely to see genome editing play a role not just in climate adaptation, but in climate change solutions as well. There will be challenges along the way both expected and unexpected, but also great leaps in progress and benefits that will move society forward. It's an exciting time to be a scientist.

Freethink: If you had to guess, what is the first disease you think we are most likely to cure, in the real world, with CRISPR?

Dr. Jennifer Doudna: Because of the progress that has already been made, sickle cell disease and beta-thalassemia are likely to be the first diseases with a CRISPR cure, but we're closely following the developments of other CRISPR clinical trials for types of cancer, a form of congenital blindness, chronic infection, and some rare genetic disorders.

The pace of clinical trials is picking up, and the list will be longer next year.

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