I like Turner and I like him a lot. However, you're letting him control the argument by agreeing with him on the 14k year date, which I don't.
How did the 80k year old Jomon and the less old Ainu get to Asia? (They came across Siberia, that's how.)
Whether that was 14k years ago or not is still subject to debate, and recently it's been a moving target. Regardless, it is only in the very recent past that it occurred, even if it was only 100,000 years ago.
The Bering land bridge is still the only mechanism which can explain a migration. Kon-tiki boats aren't very plausible for that, especially the earlier you get on the timeline.
Maybe that was before the big hyenas showed up.
From www.chowchow.org: Origin of the Chow Chow Scientific research indicates that the Chow Chow originated in China as long as 3,000 years ago, according to some canine historians. On the other hand, some scholars believe that the Chow came first from the Arctic Circle and then migrated to Mongolia, Siberia and China. The American kennel Club's publication The Complete Dog Book (1972) states that the Chow came about through a crossing of the old Mastiff of Tibet and the Samoyed from the northern parts of Siberia. However, other scholars claim that the Chow was the original ancestor of the Samoyed, the Norwegian Elk hound, the Pomeranian and the Keeshond. However, the following datum has been agreed on universally: the Chow as it is known today is easily recognizable in pottery and bas-relief sculpture of the Han Dynasty (206 B.C. to 220 A.D.); this period was marked by bureaucratic monarchy, a revival of litters and the introduction of Buddhism. It is said to be the era in which modern China was born. Other artifacts indicate that the Chow was a distinct breed in China as early as 1000 B.C., a conservative estimate, certainly.
Chows are very territorial, very protective of their owners and will try to hunt small animals (and kids). They used to be much larger than current AKC breeds and were used in war by the mongols--the Chinese called them 'bear-dogs'. They are the perhaps the oldest domesticated breed and the ancestor to all 'spitz type' dogs.
Chows have tremendously strong jaws, some of the strongest among canines, loose skin and lots of fur--a black tongue to collect heat on a siberian day...
Can you think of better a better domestic animal designed to ward off hyenas?.
Hmmmm, I have 3 chows (well, 2 1/2 really--one is part sneaky neighbor dog). They have all of the above characteristics--I should put on a show about hyenas and turn up the volume and see if they have any instinctual reaction to it....
The nastiest predator in the history of earth is us, if you want pest control give me a guy with a stone ax and a flint tipped spear.