See The Horse: A Galloping History of Humanity, Timothy C. Winegard, c. 2024

The Columbian Exchange:

The Horse: A Galloping History of Humanity, Timothy C. Winegard, c. 2024, p. 6.  

Another horse book for the bookshelf.   

"Running roughshod": a 17th century term. Described a horse that wore shoes with projecting nailheads. This gave the horse better traction while also creating a more lethal trampling weapon. Over time the term evolved to mean "attaining one's goals or desires by completely ignoring the opinions, rights, or feelings of others."

Among a gazillion other things I could mention from the book, perhaps the most important is introducing me to Brian Fagan. 

Also, from page 12: "... in 1866 the millionaire financier, banker, and philanthropist George Peabody donated $150,000 ($3 million in today's money) for the construction of the Peabody Museum of Natural History at Yale University." And then a footnote:

"Having no legitimate heir to his vast business enterprise, Peabody partnered with Junius Spencer Morgan in 1854. Their joint venture would eventually become J.P. Morgan & Co., the predecessor to three of the largest banking institutions in the world: JPMorgan Chase, Morgan Stanley, and Deutsche Bank. Peabody is also considered the first modern philanthropist."

"Bits and pieces": headgear used to direct a horse -- the buckled straps and pieces to which the bit and reins are attached. The vacant space or gap between front teeth and back teeth: the diastema. 

Recommends chapter 6, "Building Pyramids," in Sapiens: A Brief History of Humankind, Yuval Noah Harari.

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Notes

Thomas Huxley, Othneil Marsh, Richard Owen, p. 24.
Eohippus, but Richard Owen called the fossil Hyracotherium some 35 years earlier, so that's the official designation of the ur-horse, but most folks still refer to it as Eohippus.

Seventeen living species of Perissodactyla from three related families: seven Equidae (one horse, three asses, and three zebras), five Rhinocerotidae, and five Tapiridae.

Hyracotherium inhabited a vast quadrant of the planet 57 million years ago. Small, fox-sized.

Five toes, but only four touched the ground; morphing into three toes.

The progenitor of Hyracotherium remains a mystery, as the post-dinosaur epoch beginning roughly 65 million years ago was the transcending shift from reptiles to mammals.

Shared common ancestor, or "stem animal," somewhere between a 100 million and 60 million years ago.

Hyracotherium: appeared during period dubbed "Greenhouse Earth." Crocodiles, swaying palm trees in the Arctic. 

Paleontology, link here.

Evolved as climate evolved; many dead ends. Finally transitioned into modern Equus, p. 26.

55 mya: Hyracotherium established throughout Europe, Asia, India, North America (particularly Wyoming, Colorado, New Mexico).

50 mya; earth begins to cool and humidity levels dropped. Jungles, forests retreated slowly; grasses filled in.

34 - 25 mya: Hyracotherium becomes extinct, save for North America where they continued to evolve.

Middle Eocene period: North America becomes isolated from other northern landmasses. True Equidae persists only in North America.

32 mya: North American with small horse with same silhouette as modern horse. The 120-pound Miohippus would easily be recognized today as a miniature horse.

3.6 mya: discovered by Mary Leaky; side-by-side, Australopithecus and Hipparion.

4.5 - 4.0 mya: most significant global equine dispersion -- the modern genus Equus --- DNA research evolved.

Great American Interchange: newly formed Panamanian land bridge, or Isthmus of Darien, formed about 2.7 mya -- horses were among the first mammals to enter South America during a wave of accelerated migration known as the Great American Interchange.

1.0 mya -- common ancestor of both zebras and asses likely coexisted with the earliest horse in North america before dispersing into the Old World a little before 2 million years ago.

1.99 - 1.69 mya: separation of zebras and asses. Both zebras and asses continued to diverge into subspecies until roughly 150,000 years ago.

Pleistocene epoch, 2.6 mya to 12,000 years ago, no fewer than 58 species of Equus are present in the North American fossil record, with dozens living simultaneously. Certainly not "straight-line" evolution at play. 

The direct descendant of modern caballine horses showed up in North America loaded with genetic adaptation around 1.2 mya and its offspring in Europe as early as 1 mya.