With horses, dogs, cats, etc. we call them breeds because their offspring maintain those characteristics.
So, we actually do have various "races" of horses, some highly prized, such as the Arabian and Morgan.
The horses don't care, though. The only reason we care about what race people are is because there are political reasons involved.
Ever see that excellent PBS-TV show that had all the many different breeds of dawgs?
Tested them for intelligence and basic smarts?
One simple test was putting a towel of the dawg's head and counting in seconds how long it took for each breed to toss it off.
Some sat there confused like box of rocks.
Others flipped it off every time in a flash. Others were always puzzled and confused and hesitated, then removed the towel from their heads. Then there were those that took forever; even seeming too......give up!
The border collies always tested right up top.
Trying to recall the incredibly "slow" and "challenged" mutts.
They were consistently at the bottom of the pond.
Then there were those in the middle.
We had a standard Hollywood collie named "Heather".
Great guard dawg and wonderful with kids, took on a little orphaned kitten with her own litter once. Loved to run in the Sout Florida surf and swim across the Incoastal Canal and back too with me. Terrific hunter, ran with our horses and would round up our cattle with a whistle.
Our hound dawg was sharp and friendly and and protective also.
But I recall a little cocker spaniel that had the sense of many people we see and shake our heads at.
That PBS-TV dwg series was not very PC. Imagine them slowing various [races of?] people from around the globe and testing them for intelligence, alertness, basic sense.......
Genetics.
I guess a Shetland pony and a Thorobred and a draft horse are all just like different shades of hair.
Has the author of this theory finally got that silly towel off his head yet?