With horse racing back in the news because of American Pharaoh winning the Triple Crown for 3-year-old thoroughbreds (here’s side by side video comparing American Pharaoh to Secretariat in the Belmont), science blogger race/history/evolution notes points out a graph I whipped together back in 2005 showing that Kentucky Derby-winning times dropping steadily before WWII, but flattening out in more recent generations. (Note: I haven’t updated this graph for the last 11 years.)

This could be diminishing returns or, more specifically, perhaps thoroughbreds these days are lacking in genetic variation left to exploit or are too inbred? For example, the Native Dancer / Northern Dancer line shows up again and again in today’s thoroughbreds, even though this speedy pedigree may also have a tendency toward injuries.

But n/a then points to somebody else’s graph of times in the top harness race for standardbreds, which may be even more inbred:

One possible explanation is that standardbreds are allowed to be artificially inseminated while thoroughbreds have to be made the old-fashioned way, which means that standardbreds, as with dairy cattle, which continue to become more productive, are a winner take all battle among male lines, while there is more diversity among thoroughbreds because the horses have to be at the same place to mate.

But maybe it also has something to do with harness racing being even more out of fashion than thoroughbred racing. It could be that dumb eugenics tends to drive out smart eugenics, at least when the emotions of post-WWII humans get involved. Bill Nack wrote in ESPN in 2009:

Through the first 60 years of the 20th century, most of the major stallions and many of the best mares were owned and controlled by some of the oldest families and richest sporting patrons in America, by the Whitneys and Woodwards, the Bradleys and Wideners, the Klebergs and Mellons. They bred horses to race them, not to sell them, and they did so in order to compete against one other — to beat their fellow members of The Jockey Club, to see who had the fastest horse. A cardinal article of their faith was to “improve the breed,” which meant to breed a horse with great speed, stamina and soundness. In fact, on the C.V. Whitney farm in Lexington, a foal born with a crooked leg was usually taken into the woods and shot, lest he or she pollute the Whitney bloodlines with this inherent deformity. By the middle of the last century, this tight-knit racing world began to change. As these families died out and their blue-chip breeding stock was sold at dispersal auctions, the best stallions and mares fell into the hands of commercial breeders, whose central motivation was to breed, not so much a sound or durable horse, but rather an attractive horse, a “cosmetic horse,” who showed well, who had a pedigree filled with fashionable names, preferably sire lines that glowed with speed, and who thus would draw the biggest price at the fanciest yearlings sales. Because they needed to look like show horses, these hothouse yearlings were often raised in small pens and not allowed to run free, or to kick, bite and roughhouse with their peers. So, not only did the industry begin to breed horses less sound, in general, but also horses that were raised more softly, with kid gloves.

Some kinds of animal breeding, such as dairy cattle, apparently continue to make steady progress. But that’s an obscure technical field that doesn’t reflect the broader culture of its time, while thoroughbred breeding is part of modern celebrity culture.

We’ve seen something dysfunctional like this also happen with dog breeding, with most of the emphasis going into looks rather than functionality.

Back in the days of Darwin and Galton, animal breeding was a subject of immense interest to smart and rich families. For example, Harvard historian Admiral Samuel Eliot Morison (1887-1976), of the famous Boston Brahmin Eliot clan and the last Harvard professor to commute to work on horseback, makes numerous references throughout his three volume Oxford History of the American People to the role of advances in horse breeding in American history, including a lengthy profile of the 18th Century sire of a particularly useful line of walking horses. (I believe that horse is known to history as Justin Morgan.)

I bring this up because when I was rereading Morison’s trilogy around 2009 I was struck by how unusual it seemed for somebody as elite as Morison to express a deep interest in animal breeding and assume it was important and interesting to everybody else. That’s just not done these days.

On a tangentially related topic, consider rabbits as pets. I have a pet rabbit who has lived in the backyard for the last decade, and I like that he’s a low maintenance pet. He’s just kind of out there doing his rabbit thing, which is pleasing in a low key bucolic way. He adds visual interest to the backyard.

But my son has pointed out that it would seem as if rabbits could be rapidly bred to make somewhat more entertaining pets by displaying more of certain of their innate behaviors. Rabbits have fairly limited behavioral palettes, but some activities, such as binkying (jumping for joy), are amusing. But the idea of breeding a line of pets to do more of what you want them to do is not the kind of idea that comes up very often these days.