People will tell you about the Great Leap Forward, the anthropological and archaeological supposition that human culture got much more sophisticated some 40,000 years ago. A lot of them will tell you it was the development of language that caused it.
It was our partnership with wolves that did it. The domestication of the wolf into dog, creating a coevolutionary symbiotic species partnership, is what created lots of leisure time. (Not to mention helping us domesticate herd animals). As a result, with more time on our hands, we could create art and music and dance and all the other stuff they figure was cultural sophistication.
But it was dogs. Hands down, best explanation for the Great Leap Forward.
My brother had to put his dog down. He's sad about it, but as one friend put it gently, "Bob had it coming".
That's true. Boston terriers live pretty long as dogs go, and Bob, despite problems, had pushed the envelop pretty seriously.
I drank a toast to Bob last night. I toasted him, then I roasted him.
He was an ugly dog, a bug-eyed little shrimp. Bob the dog had the worst farts that are humanly possible. Bob the dog stretched the definition of symbiosis to the breaking point. Never was there a more worthless dog. He snored like a freight train. He overheated easily, what with that short snout. So, you'd wind him up, get him chasing stuff, and within a minute he's in danger of brain damage from overheating. I'm pretty sure Bob was brain damaged.
Bob the dog was also called Robert the canine. He knew he had two names. I called him Robert the canine. Whenever anyone else said Robert the canine, he would look around for Uncle John. "Uncle John's here?"
I would greet him and say "Hello my friend! Yes, yes! You are a fine fellow!", and he was a fine fellow.
Fare thee well, Bob. Hie thee to the Dog Star.