Another good one from https://notrickszone.com/2019/10/10/during-the-last-ice-age-190-ppm-co2-… … during the Late Glacial Maximum horses grazed in a forested landscape somewhat warmer than today's Arctic Alaska. In modern times the North Slope in Alaska, now north of the Arctic Circle, has a mossy tundra terrain and an absence of trees. Some 8 to 9000 years ago, the same region had both trees and many animal species that today lie 100s of km to the south. Even during the Late Glacial Maximum (LGM), 20,000 years ago, warmer temperatures prevailed (higher than in the modern world). See for example SA Kuzmina, SA Elias and AA Kotov, 'Late Quaternary Insects and Freshwater Invertebrates of the Alaskan North Slope and paleaoenvironmental reconstructions in Arctic Alaska' (published in the journal, Invertebrate Zoology, 2019, 16/2 page 89 – 125). In other words, horses could well have existed in North America prior to the introduction of horses by the Spanish. During LGM horses were the most common large animal in Alaska – followed by bison (and they survived). Horses appear to have had a substantial dietary volume of dried grasses and herbs year round, even in the winter months. Nowadays, northern Alaska is too snow covered and frigid for horses and there is too little for them to eat. What little vegetation is available in summer is later buried under snow cover – and ice. Hundreds of Pleistocene horse bones have been discovered on the North Slope – buried in silt and sand.
See also https://blogs.scientificamerican.com/tetrapod-zoology/spots-stripes-and-… …