The Human-Dog Connection: Evolutionary Catalyst(s) for each Other?

In last week’s class we discussed the decent of man, as well as the evolution of the other great apes (living and extinct). During that class, we also had the pleasure of meeting Dr. Donavan’s dog. Together as a group, we contemplated canine development vs. that of a humans and how the dog perceives his environment. As we watched the dog romp around the class room, sniffing everything and anyone in his path; we pondered together why our ancestors survived and thrived, whereas our distant cousins, the Neanderthals and the Denisovans, dwindled and died off.  Although all three hominin species cohabited in the same geographical areas of Europe and Asia, it was only anatomically modern humans (AMH), or Homo sapiens, that has survived to modern times.

I found this extremely interesting as we contemplated the fact that Neanderthals’ brains were just as large as or larger than Homo sapiens’, and in the case of bone and muscle mass, they were superior to Homo sapiens. Despite these physical attributes, some scientists write off Neanderthals as intellectually retarded in comparison to homo spines. Scientists on the Public Broadcasting Service’s (PBS) TV special suggest that we are underestimating the Neanderthals. Furthermore, we may be failing to appreciate Neanderthals’ intelligence, skills and abilities in weapon and tool creation, communication and use of symbols, as well as their art and culture. (PBS: Nova, 2013)

In fact, ancient Homo sapiens interbred with Neanderthals and  Denisovans (Scientific America, 2012). Between 1-4% of modern human DNA was inherited from these hominids in certain races of modern man (Scientific America, 2012). If Neanderthals we so close to homo sapiens in terms of size, strength, skill and intellect, what advantage(s) could have lead to our prosperity and their demise? In a mere 10,000 years after our arrival Homo sapiens had taken over. Why did this happen?

Many theories have been batted around from climate change to parasites. Some scientists propose that competition with humans probably contributed to Neanderthal extinction, Homo sapiens may have had better weapons? What if it wasn’t a better weapon that gave ancient man the edge? What if it was a better friend? Could it be that Man’s Best Friend tipped the balance of the evolutionary arms race, in our favour?

One article by Pat Shipman, in American Scientist web Magazine, suggests that “the bond between humans and dogs must have grown close very fast, as dogs took part in hunting by spotting prey animals, carrying bags and equipment, and, in return, sharing in the spoils”(Shipman, 2012). All of these fabulous benefits of our Human-Canine teamwork would have enabled Homo sapiens to maintain larger families and reproduce at faster rates with healthier offspring, which would have led to the speedy outnumbering of the Neanderthals (Shipman, 2012). During the 10,000-year Human-Neanderthal overlap period, human populations increased tenfold (Shipman, 2012). In this span, “all dog bones found so far have been exclusively in Homo sapiens sites. If Neanderthals did not have domestic dogs and anatomically modern humans did, these hunting companions could have made all the difference in the modern human–Neanderthal competition” (Shipman, 2012).

Although we no longer have mammoth hunts today, a research team from Finland compared the success of hunting moose with and without dogs, and discovered that using man’s best friend increased the yield of carcass weight by an average of 56 percent for each hunter ” (Koster & Tankersley, 2012).

A study by Ruusila and Pesonen (2004), demonstrated that 85 percent of the pray brought down in the observed hunts employed the use of dogs.  Dogs are essential for locating pray, the hunters that participated in the study were six to nine times more likely to find pray using dogs and hunts were 57 percent faster when dogs were on the trail (Ruusila & Pesonen,2004)

Furthermore, it has been purposed that that proto dogs and ancient man friendship was so crucial that both spices may have evolved interactively (Shipman, 2012). Dogs have developed the capability to follow the gaze of their human owner – “meaning that when we look toward something without pointing or nodding toward it, dogs have learned to recognize that we’re directing their attention toward it” (Shipman, 2012).

Most other animals, even our closet living relative the primates, lack the important ability to fallow a human gaze, or the gesture of physically pointing to an object. Since humans are the only species that utilize pointing to objects as a form of communication, it is quite remarkable that any other spices could understand it (BBC 2010). Dogs have highly tuned abilities to follow and understand verbal and non verbal cues with tremendous accuracy: being able to follow a human gaze would be very helpful during a hunt.

This information would come of little shock to most canine aficionados, but what may surprise them, is dogs interpret human expressions in the same manner as humans! Humans have what is called a left side bias (BBC 2010). We utilize the right side of the face when attempting to gage emotions on a human subject, as it is a more faithful representation of our emotion (BBC 2010).  It had previously been believed that shifting our gaze to the left was a uniquely human trait, this turned out to be false (BBC 2010). Dogs are the only other animal that utilizes the left gaze bias to read human faces (BBC 2010).  No other animal has this relationship with the human face; furthermore, dogs do not do this with other dogs or animals (BBC 2010). This ability to correctly “read” human emotion gives the dog a biological advantage. Being able to understand if a human is angry or potentially harmful, or that it is safe to approach a human that is smiling would help lay the foundation for a very powerful bond (BBC 2010).

The skill of deciphering your best friend’s emotions is not solely a talent that our canine counterparts possess. There are common claims made by dog owners that they can understand what their dog’s barks signify. Could it be possible, they have domesticated us while we were domesticating them? Studies revealed that humans are amazingly accurate when it comes to interpreting our dogs’ barks! Humans are able to discriminate six different barks, by utilizing qualities such as frequency, tonality and the intervals of the barks, (BBC 2010). Being able to decipher what proto-dog was trying to tell ancient man, could have been a matter of life and death for our ancestors!

Perhaps what is most amazing is that scientists today believe that our best friend is still evolving in step with us. Certain dogs are beginning to develop enhanced intellects. What is perhaps even more amazing is that we humans may not be cluing in to it.

There has been at least two canines studied for their superior cognitive abilities (Chaser and another unnamed dog, both are Border Collies) (PBS:NOVA; 2011, 2013) “Researchers studying dog genomes found a gene that may be responsible” for this new enhanced intelligence. (PBS:NOVA; 2011)  “It’s called CTNND2, in humans this gene is responsible for normal cognitive development, the border collie genome shows selective breeding for this gene!” (PBS:NOVA; 2011). Throughout our evolution humans have bred our best friend for intelligence and skill, and then things changed.

 Around the time of the Victorian era, humans had become obsessed with how our dogs looked and if they were a pure breed. The value placed on intelligence and skill has fallen to the wayside. But what if we just bred for intelligence? What if the CTNND2 gene and other types of genes related to cognitive enhancements and emotional intellect were selectively bred for, in lieu of looks? Just how much more amazing could our best friend potentially become!?


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One response to “The Human-Dog Connection: Evolutionary Catalyst(s) for each Other?

  1. Hello Allie,

    I really enjoyed your exploration of the contribution of dogs to the survival of ancient man and the continued Human-Canine teamwork and companionship with modern man. While our course material has presented evidence that humans are superior to other species, including dogs, in their capabilities of teaching and learning, it is evident from classroom discussions and several blog entries that our dogs and other pets are much valued companions.

    As the “mother” of a much loved but now departed dog, I appreciated the evidence you provided in your blog to support the notion that dogs may deserve more credit for their intelligence. It was particularly intriguing to read about the possibility that dogs and humans have evolved interactively and that dogs have developed the unique capabilities of humans such as following a gaze and reading human faces and emotions. It makes me think that even though dogs did not evolve from a common ancestor, like the ape, we really did make the best choice in selecting the dog to be man’s best friend. Now may be the time to put aside the quest for the best looking dog and focus on gaining the most intelligent and loyal companion!

    Thank you for a great read!

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