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EVOLUTION OF "MAN'S BEST FRIEND"

Posted Apr 21 2013 12:00am


Archaeology has placed the earliest known domestication of dogs approximately at 30,000 BC, and with certainty at 7,000 BC.  Evidence suggests that dogs were first domesticated in southern East Asia.
Due to the difficulty in assessing the structural differences in bones, the identification of a domestic dog based on cultural evidence is of special value. Perhaps the earliest clear evidence for this domestication is the first dog found buried together with human from 12,000 years ago in Palestine and a burial site in Germany called Bonn-Oberkassel with joint human and dog interments dating to 14,000 years ago.
In 2008, re-examination of material excavated from Goyet Cave in Belgium in the late 19th century resulted in the identification of a 31,700 year old dog, a large and powerful animal which ate reindeer, musk oxen and horses. This dog was part of the Aurignacian culture that had produced the art in Chauvet Cave. In 2010, the remains of a 33,000 year old dog were found in the Altai Mountains of southern Siberia. DNA analysis published in 2013 affirmed that it was more closely related to modern dogs than to wolves.  In 2011, the skeleton of a 26,000 to 27,000 year old dog was found in the Czech Republic. It had been interred with a mammoth bone in its mouth—perhaps to assist its journey in the afterlife. Domestication of the wolf over time has produced a number of physical or morphological changes. These include: a reduction in overall size; changes in coat colouration and markings; a shorter jaw initially with crowding of the teeth and, later, with the shrinking in size of the teeth; a reduction in brain size and thus in cranial capacity (particularly those areas relating to alertness and sensory processing, necessary in the wild); and the development of a pronounced “stop”, or vertical drop in front of the forehead (brachycephaly). Certain wolf-like behaviors, such as the regurgitation of partially digested food for the young, have also disappeared. Adapted from:  http://en.wikipedia.org/wiki/Origin_of_the_domestic_dog  
EOB-2....

How many of you are sitting there comfortably, looking at your "best friend" (the 4-legged one), wondering just which parts of your pooch bear the most resemblance to a wolf?  There's no doubt that man's best friend has taken on a lot of different appearances and traits...however, genetic and archaeological evidence do provide a direct pathway from Canis familiaris (your "best friend") back to Canis lupus (the wolf).


 
How Dogs Evolved Into 'Our Best Friends'
Dogs have aided humans for thousands of years. Man's best friend has provided protection, companionship and hunting assistance since the days of the earliest human settlements. But how and when dogs evolved from wolves is a matter of debate. Naturalist Mark Derr says there are two main schools of thought: Some researchers believe that humans domesticated wolves who were scrounging around their villages for trash. Others think that humans were taking care of wolves from the time they were puppies — until enough puppies were tamed and they somehow then evolved into dogs. "Neither explanation seems satisfactory," writes Derr in How the Dog Became the Dog — From Wolves to Our Best Friends. "That is why there's no consensus." In his book, Derr explores how the relationship between humans and wolves developed, and how that relationship then influenced the physical evolution of wolves into dogs. He tells Fresh Air's Dave Davies that he believes humans and wolves developed a close relationship after recognizing themselves in each other while hunting on the trail of big game. "[That's when] they started traveling together, and they've been at it ever since," he says. "The dog is a creation of wolves and humans — of two equal beings that came together at a certain point in history and have been together ever since." Derr says our ancestors likely followed behind wolves as they hunted for game on the trail. Wolves, in turn, learned to wait for scraps from bipedal hunters — who were far more accurate with their rudimentary weapons than the wolves were with their teeth. The wolf could say, 'These people are far more profligate hunters than we are. When they go out, they always leave a surplus. It's easier for us to take the scraps that they have than to hunt,'" says Derr. "Hunting is a highly energetic activity. And they could learn from each other, just by observing each other." As humans and wolves began to work and live together, physical features on the wolf began to change: Its skeletal frame grew smaller, and its jaw shortened. Wolves that socialized well with humans began to travel with them, and then were able to pass on their genes. "You had populations of dog-wolves that became isolated, and in doing so, they began to inbreed," says Derr. "And when you inbreed, you get genetic peculiarities that arise, and then those peculiarities become part of the population. If they work or become popular or have some function of beauty or utility, then they were kept by the humans — and that population then spreads those through other populations through breeding." Fossils of wolves and dogs have been found in early hunting camps. In China, researchers have found evidence that some hunters were raising millet to feed to their hunting companions. "This kept the dogs alive during times of thin meat," says Derr. "When they weren't getting as much meat as they wanted, they would feed [the dogs] millet. That would indicate that the early dog was being used as a hunter, but also that it was highly valued." On puppies "There's something about them that makes us friends with them. There are people who dislike dogs for sure. But dogs also have an uncanny ability ... to walk in a room and pick out the one or two who seem to dislike dogs the most and make friends with them. It's happened to me with some of my dogs on numerous occasions. I think there's a deep — some people call it love, I call it a 'deep empathy' between these two species that resonates with each other in a way that makes them comprehensible to each other, even though they don't speak the same language." On small dogs "There are some people who suggest that the small dog, because of its size, was a curiosity, an easier dog to have as a companion. In much of American history and even today, you'll find people who have two dogs: a large dog, who is in the yard, and a small dog, whose job is to kill rats and make a noise if somebody comes near, be a companion or playmate for the children, or a guardian." On the cultural evolution of dogs "This is one of the reasons why people like to speak of the dog as a separate species than the wolf, even though they're so closely related. The dog lives with us in a way that wolves don't. It is created by us in different ways." On breeding "I'll say it bluntly, and it has to be said: Some of these breeds are incapable of giving birth without C-section. ... I think that it certainly is wrong to produce animals that aren't healthy. It's bad for the animal and bad for the people who take them into their homes and find out that this dog they love is going to die at a very young age because of an inheritable disease. ... We really should ask ourselves whether it is fair to the animal to do that. I am of the opinion that it's not." Adapted from:  http://www.npr.org/2011/11/08/142100653/how-dogs-evolved-into-our-best-friends?ps=cprs   Dog: man's best friend for over 33,000 years He's been man's best friend for generations An ancient dog skull found in Siberia and dating back 33,000 years presents some of the oldest known evidence of dog domestication. When combined with a similar find in Belgium, the two skulls indicate that the domestication of dogs by humans occurred repeatedly throughout early human history at different geographic locations -- rather than at a single domestication event, as previously believed. "Both the Belgian find and the Siberian find are domesticated species based on morphological characteristics," said Greg Hodgins, a researcher at the University of Arizona's Accelerator Mass Spectrometry Laboratory and co-author of a study reporting the find. "Essentially, wolves have long thin snouts and their teeth are not crowded, and domestication results in this shortening of the snout and widening of the jaws and crowding of the teeth." The Altai Mountain skull is extraordinarily well preserved, Hodgins said, enabling scientists to make multiple measurements of the skull, teeth and mandibles that might not be possible on less well-preserved remains. "The argument that it is domesticated is pretty solid," he said. "What's interesting is that it doesn't appear to be an ancestor of modern dogs." At 33,000 years old, neither the Belgian nor the Siberian domesticated lineages appear to have survived earth's last ice age. Still, they show, just how far back our special relationship with our canine companions goes, Hodgins said. "The interesting thing is that typically we think of domestication as being cows, sheep and goats, things that produce food through meat or secondary agricultural products such as milk, cheese and wool and things like that," he said. "Those are different relationships than humans may have with dogs. The dogs are not necessarily providing products or meat. They are probably providing protection, companionship and perhaps helping on the hunt." "And it's really interesting that this appears to have happened first out of all human relationships with animals." Adapted from:  http://www.foxnews.com/scitech/2012/01/24/dog-mans-best-friend-for-over-33000-years/ and…. To come to the finding, a team led by Anna Druzhkova of the Russian Academy of Sciences sequenced mitochondrial DNA taken from one of the skull’s teeth. This type of genetic material comes from an organelle inside each cell called the mitochondria, which has a distinct type of DNA that’s separate from the cell’s normal chromosomes. For each individual, mitochondrial DNA is inherited directly from one’s mother without any modifications and thus remains relatively constant over generations, except for the gradual effect of mutations. Similarities found in such DNA collected from various animals helps scientists understand the evolutionary relationships between species. The research team compared their sample of mitochondrial DNA from the ancient skull with samples from 70 different modern breeds of dog, along with 30 different wolf and 4 different coyote DNA samples. Their analysis found that the fossil’s DNA didn’t match any of the other samples perfectly, but most closely resembled the modern dog breeds, sharing the most similarities with Tibetan Mastiffs, Newfoundlands and Siberian Huskies in particular. Scientists know that dogs evolved as a result of the domestication of wolves, but the specific time and location of this domestication is still poorly understood—and this discovery further complicates that picture. Most experts agree that dogs predate the invention of agriculture (which happened roughly 10,000 years ago), but some say that domestication may have occurred as long as 100,000 years ago. This finding—and the previous radiocarbon dating of the skull which established its age—set that event to at least 33,000 years ago. However, dogs may have been domesticated from wolves multiple times, and this breed of Siberian dog may have actually gone extinct, rather than serving as an ancestor for modern dogs. Archaeological evidence indicates that, with the onset of the last glacial maximum (around 26,000 years ago), humans in this area of Siberia may have stopped domesticating dogs, maybe due to food scarcity. In that case, an independent domestication elsewhere may have led to the dogs of today. On the other hand, domestication in the vicinity of the Altai Mountains, as evidenced by this finding, may have led to the geographic spread of dogs elsewhere in Asia and Europe, even if they died out in Siberia. Previously, many have suggested that the first domestication occurred in the Middle East or East Asia, but this skull could force scientists to rethink their theories. The research team behind the analysis notes that finding more ancient dog remains will help us in putting together the puzzle. Adapted from:  http://blogs.smithsonianmag.com/science/2013/03/this-33000-year-old-skull-belonged-to-one-of-the-worlds-first-dogs/?utm_source=smithsoniantopic&utm_medium=email&utm_campaign=20130310-Weekender





Why Dogs are More Like Humans Than Wolves Brian Hare began studying dog intelligence as an undergraduate at Emory University in the 1990s, after realizing that Oreo, his Labrador retriever, had a remarkable ability. Unlike other animals, even chimpanzees, Oreo could interpret human gestures, following a person’s gaze or a pointing finger. From early experiments with the family dogs in his parents’ Atlanta garage, Hare went on to found the Canine Cognition Center at Duke University. Now, in The Genius of Dogs: How Dogs are Smarter than You Think, Hare and coauthor Vanessa Woods detail recent research about man’s brilliant best friend. Not only do dogs possess social intelligence far beyond that of their wolf ancestors, Hare says, but in many ways they’re more like us than our own primate relatives. Hare is also the lead scientist behind Dognition.com, a new website that offers pet owners the opportunity to participate in a massive citizen science project—and uncover the genius in their own precious pooches. What is the secret to dogs’ intelligence? The genius of dogs is that they use probably the most powerful tool on Earth to solve problems—humans. At one point in wolf evolution, a group of wolves decided to take advantage of humans, and they have been really successful because of it. It’s probably not a surprise to people that dogs are socially tuned-in to us. But I think what’s new is the understanding that this skill is absolutely remarkable in the animal world. When you talk about survival of the fittest, most people think nature is “red in tooth and claw.” But dogs domesticated themselves through a natural process, where the less aggressive, most friendly, tolerant individuals actually did much better. How has the scientific understanding of dogs changed? We’ve learned more in the past 10 years than in the previous 100 years. When identifying intelligence in animals, what people are most interested in is where animals make inferences. These are situations in which they can’t actually perceive a solution, so they have to infer it spontaneously. If you are going to find that kind of intelligence, you’re not going to find it in a dog, or so it was thought. Scientists had theorized that dogs, through domestication, have become dumbed-down, because they just sit around and take scraps from us. What do they need to be smart about? The guess was animals like a bonobo or a dolphin or other charismatic megafauna were where to look. But it turns out in many ways dogs are more like us than even great apes. How are they like us? Dogs are the only species that have demonstrated that they can learn words in a manner similar to a little kid. It’s not that other species that we think of as being highly intelligent, like bonobos and dolphins, can’t become sophisticated at communicating using symbols, but there’s some nice evidence that dogs are using an inferential strategy, which takes advantage of what’s called the principle of exclusion. They know that a number of objects are named or labeled with a sound, and when a new one is introduced that they do not have a label for, and they hear a new sound that they’ve never heard before, they infer that the new sound must apply to this new object. That has only been observed in human children before. That was a big shocker, and it’s been replicated. It even gets crazier than that—several border collies are using what’s called the principal of iconicity. You can show them a two-dimensional picture, and they will then go fetch the object in the picture. That’s something people thought only kids could do, and that it would only be in a linguistic species that that would be possible. That’s amazing, but it’s a small sample size—isn’t it possible these dogs were outliers? We don’t know. I don’t think it’s chance that the dogs that have demonstrated this are border collies. But that is not to say that border collies are somehow the most intelligent breed. All dogs are probably able to make the type of inferences that the border collies are making. The question is, can they use that exclusionary principle when learning words? It’s entirely possible that all of our dogs have this hidden talent that we just don’t know how to take advantage of. What are some other new findings about dog intelligence? There’s a lot of research into how dogs solve problems. For instance, in a new experiment, a dog demonstrated opening a sliding door, using one of two techniques. It turns out other dogs will copy the first dog and use that same technique the very first time they open the door. That is not something that most people would have expected. [A hundred years ago, British psychologist] C. Lloyd Morgan was one of the first people to write about animal intelligence from an experimental perspective. One of the great anecdotes he tells is about how his dog Tony struggled to open a gate, and through trial and error, he slowly learned a solution. It looked like Tony the terrier was a genius, but because Morgan had watched the problem-solving develop, he knew that Tony didn’t understand anything, that it was all chance trial and error. Morgan then concluded that when you see animals doing intelligent things, you must consider that there’s a very low-level mechanism that allowed them to solve the problem. But the new finding is, if he had only shown Tony how to open the gate, Tony could have learned almost immediately how to do it. You make the problem social and dogs do fantastically. You also cite studies that show dogs can be deceptive. How does that demonstrate genius? Those studies show that dogs are using information about what humans can see or hear to make decisions about how to behave around us. In one study, dogs spontaneously avoid retrieving food from a box with noisemakers when they have been told not to eat it, [instead choosing to steal food from a box that a human has demonstrated does not make noise]. This suggests they might be aware of what we can and cannot hear. Similarly, a number of studies have shown that dogs avoid misbehaving if you are watching them, but are more likely to act up if you have your back turned, or even your eyes closed! So there is such thing as a bad dog. But can this new science of dog cognition help us train them better? No pun intended, I don’t really have a dog in the fight about how to train dogs, but it’s an important question. People love dogs, and they want to help their dogs have a rich life, and they can do that by helping their dogs obey some simple principles. But how do you get a dog to do that? One of the big schools of thought is you have to really be an alpha dog. You have to make sure the dog doesn’t think he can boss you around. That premise is probably based on some faulty rationale, that dogs evolved from wolves, and wolves have a very strict hierarchy. That’s a reasonable hypothesis, except that there’s one major problem: dogs are not wolves. Looking at feral dogs, what people have found is that they don’t have a strict hierarchy. It’s not that you follow the dominant individual. With feral dogs, the leader is the individual that has the most friendships in the group. It’s not about dominance. There’s another school of training, which says that the more you practice the better they’ll be at sitting, staying, listening to you, obeying, etc. But there are studies that show that dogs that are trained less intensely actually learn faster and retain the information they learn longer. If you force animals to perform over and over, it actually makes a response less flexible. Here’s a question that could get us in trouble. Are dogs smarter than cats? It’s a very difficult question to answer in any meaningful way. I could ask you, which is a better tool, a hammer or a screwdriver? They’re designed to do different things. Compare the origins of these animals in the wild, their progenitors, the wolf and the wild African cat. You have one that is an endurance runner, a pack animal that relies on cooperation. You have another that is a relatively asocial, stalking hunter that relies on stealth to be successful. These are completely different social systems and ways of life, and evolution shaped those minds to be really different because they do completely different things in terms of how they make a living. Fair enough. In addition to dog and cat partisans, I’m guessing that many pet owners will have another response to your book: “There’s no way my dog is a genius. He drinks out of the toilet and chases his own tail.” Would these people be wrong? Everybody loves to talk about how amazing humans are as a species in terms of innovation and technology. We’ve invented the Internet and the iPad, and we have an International Space Station. Yes, as a species we’ve done that, but I can assure you that if somebody said to me today, “You have to invent the next iPad,” you might as well just shoot me. There’s also tremendous individual variation in dogs. In the case of the dog that chases his own tail, that may be a dog that the person thinks is a little bit on the dumb side, but there are some domains of intelligence that people aren’t really thinking about. Just because one individual dog isn’t particularly good at using gestures, for example, it doesn’t mean that they’re not absolutely remarkable in their memory, or that they can’t use your visual perspective to deceive you. One of the things we’re trying to do in the book is change the conversation about what is intelligence. A lot of people may find out, the dog that just chases his tail, there’s actually a lot more there than they expected. Adapted from:  http://www.smithsonianmag.com/ideas-innovations/Why-Dogs-are-More-Like-Humans-Than-Wolves-192083131.html?utm_source=smithsoniansciandnat&utm_medium=email&utm_campaign=201302-science

OK, now, be honest...how could anyone even think that either one of these cuties could have descended from a pack of wolves???




 Any questions or comments should be sent to Helpful Buckeye at: dogcatvethelp@gmail.com   or submitted at the "Comment" section at the end of this issue. ~~The goal of this blog is to provide general information and advice to help you be a better pet owner and to have a more rewarding relationship with your pet. This blog does not intend to replace the professional one-on-one care your pet receives from a practicing veterinarian. When in doubt about your pet's health, always visit a veterinarian.~~
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