Okay ....what evidence to you have to back up that hypothesis? [that dogs were the catalyst for the invention of civilization]
It's circumstantial, but that's good enough for a hypothesis to be treated with respect in the scientific method. Human tribes were extremely hostile to each other in the Paleolithic Era. Forensic analysis of skeletons using modern technology has discovered that more than half of adult humans in that era were killed by violence. Suddenly the first evidence of humans and dogs living together shows up, and within a couple of thousand years they're making nice with the other tribes. It's not proof but I haven't come across a better hypothesis to explain why the Agricultural Revolution and the transition to village life, which required living in harmony and cooperation with non-family members, occurred when it did--in multiple locations.
What evidence do you have for proposing that hypothesis? [that dogs came to live with humans voluntarily]
Again, circumstantial and again that's enough. Humans had not mastered the technology of animal husbandry at that time. There is evidence of earlier experiments with large, docile herbivores that could be easily captured. To capture fast-moving, intelligent predators that travel in packs would have been a remarkable feat. Cooperation would have made it more feasible. The somewhat omnivorous diet and scavenging instinct of most canids would have made our garbage tempting as it does today to wolves and coyotes. I saw footage of an African tribesman holding out a beef leg bone to a hyena, and after a long period of patience (I don't know how many weeks, years or generations it took) the hyena peacefully accepted the offering.
It might be hyperbolic of me to insist that it was dogs who adopted humans, but at the very least it was a mutual transaction.
Native Americans didn't have to make those intermediate steps. [Domesticating easier species before tackling horses.] So, again, what's your evidence for the hypo?
I don't understand. Horses are not native to North America. They were brought here, already domesticated, by the Europeans. The Indians bartered or stole their herds, or picked up those left riderless in combat, and learned how to "break" them for riding by watching us do it.
Nope, I checked ...it just asked what was the largest impact on humans. And as to rats not being domesticated, that could be argued as well.
No. "Domestication" requires captive, and at least rudimentarily selective, breeding. Animals that breed ferally and then hang out with us are not domesticated, nor are captive animals that can only be bred by AI. This obviously bears on the timeline for the domestication of cats. Unlike dogs they're not pack-social by instinct so they would not have so readily and quickly established companionship with another species that clearly merited the respect of alpha status.
And those rats caused the deaths of about half of Europe's population at the time. Pretty large impact wouldn't you say?
It was more like one-third. It's been argued that the plague was a major factor in Europe's economic improvement and concomitant rise out of the Dark Ages. When the plague was over everyone had 50% more wealth.
so the animal that was domesticated first was the one that had the hugest impact?
No, that wasn't my point and forgive me if I wasn't clear. I was just suggesting that the impact of the horse on human culture must be shared with the other large herbivores that were domesticated first. Dogs came out of nowhere in the depths of the Stone Age. Horses were the latest in a long line of exercises in animal husbandry throughout the Neolithic Era and the Age of Civilization.
How do we know it wasn't a monkey in Africa or a chicken in South America?
Because archeologists make it their business to figure that stuff out. They've got rather precise dates for the first evidence of domestication of every tamed animal you can name. I haven't got the whole list here but it looks like sheep and goats came first, then pigs and cattle, then horses and donkeys, then camels and ferrets, then elephants and rabbits. (And I could be off there Max but it hardly matters in this context.) With various birds and smaller game animals along the way. The New World had its own species and timeline. Since nobody could figure out what to do with bison they were rather limited. Llamas and the other camelids, turkeys, guinea pigs. Amazingly, the large, docile and meaty capybara has only been domesticated within our lifetimes, strictly as a pet. Just as amazingly, the North American Indians never tried it with mountain goats, deer or javelinas, so they only had half of agricultural technology (plants) and had to hunt for their protein.
The Eskimo-Aleut didn't even domesticate the reindeer (called "caribou" here but it's the same animal) like the cousins they left behind in Asia did.
Take it even further than that, Orleander, think of plowing the ground, planting crops and harvesting them without horses.
Uh dude, you're forgetting that millions of people have used oxen, donkeys, yaks and llamas as beasts of burden. And let's not forget elephants.

The only civilization that was built without draft animals was the Olmec, because there were no large herbivores in Mesoamerica. Gotta give those guys credit.
I agree that the military would have been hampered, but think in term of normal, non-war life. Even intra-city commerce would have been impossible without horses to pull the cargo wagons. City delivery without horses? That would have been a damned small city, wouldn't it?
Oh come on. Haven't you seen any movies set in ancient times where everything is hauled by asses? Most people couldn't afford a horse! They were the Cadillac of draft animals.
And since you love to use the anomalies of the New World people to shoot down hypotheses, how do you explain the fact that the Olmecs and their successors, the Maya and Aztecs, ran their impressively large cities quite well without draft animals?
And don't forget that we have abundant historical accounts of large dogs being used to haul carts, even quite recently (e.g., the Rottweiler). A lot of us dog breeders wonder whether that was the reason the St. Bernard was developed. Dogs with their separated toes can be more sure-footed than hooved animals in rugged mountains. I'm pretty sure there were no large dogs in the Americas so that still doesn't explain the Olmecs.
I'll take my dog over about 350,000,000 people right about now!
Well you're certainly a counterexample to my hypothesis that living with dogs made people more sociable.
