Okay...and? Where are you going with this? Horses were on the North American continent and then went extinct.( this is debated).They were brought by the Spanish in the early 1500's. Probably before is debated as well. Either way what are you trying to say?

Now, new research out of the University of California Santa Cruz’s prestigious Paleogenomics Lab sheds new light on the argument by tying the DNA of the modern-day horse to its ancient ancestry on the North American continent.

https://americanwildhorsecampaign.org/media/scientific-research-alert-research-cements-native-ancestry-americas-wild-horses

https://awionline.org/content/wild-horses-native-north-american-wildlife

https://ictnews.org/news/yes-world-there-were-horses-in-native-culture-before-the-settlers-came