What is a dog anyway?
- December 10, 2022
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Geographer Jared Diamond has called domestication the worst mistake humans have ever made. He blames domestication for the rise of monoculture, which he says is leading to a larger, more sedentary human population where disease can spread quickly. In addition, sedentary populations dependent on crops are becoming more vulnerable to climate change, crop diseases and natural disasters. Domestication, says Diamond, also caused a precipitous decline in biodiversity and a rise in social inequality and wars between humans.
Sounds like a pretty bad choice.
And yet the first domestication – the transformation of wolves into dogs – was an impressive feat. People back then had to evaluate each new species they encountered: will it kill me or can I kill it? If it kills me, how is it stronger or more skilled than me? If I kill it, what can I gain?
Eventually, humans began to realize that instead of killing another species, living with it might be beneficial. Paradoxically, our ancestors chose one of the most dangerous predators to live with: the gray wolf. I’m a paleoanthropologist who has researched the effects of domestication. The origin of dogs is disputed, but I posit that taming wolves into dogs may have helped the first modern humans to outperform other hominins like Neanderthals.
What was the benefit of working with wolves? Modern wolves have greater endurance than humans and a top speed of up to 40 miles per hour, compared to 30 to 45 miles per hour for dogs and just 27 miles per hour for a world-class runner like Usain Bolt. Wolves have a superior sense of smell (they have more than 50 times more olfactory receptors than elephants, which require painstaking retraining with each generation. In fact, most animals that humans have attempted to domesticate have refused. A striking example is the beautiful zebra , which despite being closely related to the domestic horse and donkey, remains one of the most dangerous animals in the zoo.
Because domestication humans do), sharper teeth and claws than humans and better night vision. Borrowing or co-opting these skills resulted in a major improvement in human hunting and survival. But the wild wolf had to benefit from the arrangement. The main advantage for the canids would have been less danger and more meat – their job was to find, track and surround the prey while humans with ranged weapons did the dangerous job of killing them. Karen Lupo and Jeremy Koster have shown in independent studies that hunting with a dog yields more meat per hour of effort than hunting without a dog, although the dogs eat some of the meat.
Forming an effective wolf-human pack meant developing a means of communication and making genetic modifications to make this collaboration permanent. Domestication is not domestication as used in wild born Asians of all animals, involves selection (by humans) for genetic traits, it takes generations to achieve. Some scholars place the earliest changes around 30,000 years ago, while others see domesticated dogs as late as around 16,000 years ago. Remarkably, humans sought to domesticate not only the gentle or tasty animals like cows and sheep, but also fierce competitors who competed with us for food, water, and safe places to raise their young. I assume that allied with wolves allowed modern Homo sapiens to outcompete and survive earlier species like Neanderthals, who had thrived in Europe long before modern humans got there. I see no amazingly large change in weaponry in the earliest modern human sites that would be responsible for their survival. Dogs would not only have aided modern man in hunting, but would also have guarded the carcass after killing it from scavengers.
Dogs excel at an unusually wide range of duties: acting as companions; as a porter; as guards and living weapons; as disease or contraband detectors; and as a tracker. They provide fur, meat, potentially useful bones for crafting tools, and more dogs. They are particularly suitable as blankets. Dog bones or teeth have also served as jewelry to identify members of a particular human group. Despite the inherent risks of being closely associated with another large carnivore, this versatility may have fueled the spread of dog breeds in the 18th and 19th centuries. Indeed, one’s job or social status has long been signaled by the dog one owns, from the Pekingese of the Chinese kings to the Saluki, the racing dog of the Egyptian kings, the corgis of the late Queen Elizabeth II, and the great shepherds of the Pyrenees.
Why is the origin of dogs controversial? We don’t know how to define what a dog is. First, there is not a single feature that we can observe in modern or ancient canids that characterizes them as canines. Dogs have a look about them and a familiar demeanor, but no distinct trait. Genetically, the number of genes that make a dog a dog is difficult to quantify, even when we have the entire genome of one specimen. For example, there are about 16,000 base pairs in mitochondrial DNA inherited from the mother. How many genes need to be sequenced to identify a species? We don’t know because there are mutations that occur but don’t do much. How many must be changed so that the specimen becomes a dog instead of a wolf? Basically we don’t know.
Second, there is a fundamental problem in dating the progression from wolf to dog. If the sample is less than 50,000 years old, bone, charcoal, and other organic matter can be dated based on the percentage of radioactive carbon that has broken down into non-radioactive nitrogen. Geneticists use the number of mutations in the genome to date samples, but mutations can occur faster or slower than “normal.” Genetic dating is not accurate. Importantly, not all animals survive as fossils, so many records of life on Earth are invisible.
Finally, I’m afraid we’ve neglected some of the evidence – where the iconic Australian dingo fits in. After evolving in Africa, modern humans reached Australia before reaching Central Europe, America, or Antarctica. Madjedbebe, the earliest archaeological site in Australia, is dated at around 65,000 years. Researchers accepting this date cannot find any trace of dogs or domestic canids anywhere in the world at this time. Genetic estimates suggest that dingoes arrived in Australia around 18,000 years ago, but there are no dingo bones from more than around 4,000 years ago. Could they have been in Australia for so long and not left a mark?
Dingoes feature prominently in Australian Indigenous culture and mythology, but dingoes or their ancestors are not marsupials like any other large-bodied mammal endemic to Australia. (Every placental mammal in Australia — true dogs, horses, rabbits, cats, and rats, for example — was introduced by humans.) Unfortunately, many researchers studying the origins of dogs have dismissed dingoes as unimportant, but they’re the only alternative story the transformation of wild canids into dogs that we have. The distinctive features of dingoes are fascinating. Why are they so good at climbing and manipulating objects with their paws? Why are they howling but not barking? Why do they breed like wolves only once a year and mature slowly? Why are they so resistant to captivity? What distinguishes dingoes from dogs? Was it the way of life of Australia’s indigenous people that led to a different type of domestication? as Adam Brumm and Loukas Koungoulus suggested? Was it isolation from other canids? Did dingo ancestors have something that later canids lacked?
We take for granted the origins of this species so dear to us. But to really understand what a dog is, we need to ask more questions.
This is an opinion and analytical article, and the views expressed by the author or authors do not necessarily reflect those of Scientific American.