- Horses
- American Lion
- Camels
- Cheetah
- Jaguar
- Stag-moose
- Giant Beaver
- Giant Peccaries
- Columbian Mammoth (woolys live in the arctic)
- Mastadon
- Gian Sloths (Confined to a few enclaves)
What are the effects on the Native American cultures? Timeline will follow soon but I need input.
Firstly, let me say that I second the notion that it's great that someone is seriously going to do a timeline with American domesticates-it's an idea that is full of potential, could produce many varied timelines without becoming a cliche, but is much more talked about than done. That said, let's look at your list of animals one by one.
1. Horses-Once domesticated, horses can serve as a near-perfect domestic animal-they produce meat, milk, are adaptable, can carry riders for trade or warfare, and can be used for hard labor. Expect to see larger empires and knightly classes in Native American society with these animals, as well as larger, more complex nomadic societies. Likely first site of domestication would be in Mesoamerica, which is in the range of the fossils identified as Equus conversidens.
2. American Lion-the survival of its prey means this animal will live a little longer, but I don't see it competing very well with human hunters. Even if it survives ancient Native American civilizations (probably in isolated areas with low human populations), I doubt it could survive into the modern era.
3. Camels-Like horses, can provide meat, milk, labor, and transport. Unlike horses, not very adaptable. They're stuck in desert environments IOTL, and likely will be that way ITTL. Some desert cultures could develop along parallel lines with nomadic cultures in the Middle East and North Africa, but camels are not going to have a massive impact outside of those deserts.
4. Cheetah-This takes a degree of handwaving, but if you decree that cheetahs in North America are easier to breed in captivity than old world cheetahs, this could result in them being domesticated and used as the equivalent of hunting dogs by Native Americans, which I would find fascinating. Of course, this would assume that they are as easy to tame and as safe for humans as the cheetahs in Africa as well.
5. Jaguars-read Wikipedia article on OTL's Jaguars. Apply to North America. Outside of being an inspiration for myths, I don't see this animal having a big impact on N.A. cultures.
6. Stag-Moose: I don't know much about this animal, so I can't say. But if it survived, the relict population would probably be much smaller in body size than the Ice-Age population.
7. Giant Beaver-see wikipedia article on OTL's beaver. Multiply body size by three, decrease population size by same. I doubt this species would survive the trade in pelts with Europeans, but it could bring some real wealth to N.A. cultures in a post-European contact world.
8. Giant Peccaries-Depends on the species. Some were solitary, and so would not have made good domesticates (you can't keep them in herds). Others lived in herds, so could have become a rough equivalent to OTL's pigs (although the Flat-Headed peccary of North America seems to have preferred a dryer habitat than pigs, which would make its husbandry very different).
9. Mammoths and Mastadons: Assuming these managed to survive alongside human civilizations, they would probably be treated like elephants of our time. A large and complex society might capture some from the wild and use them as mounts and beasts of burden, but their size would make them too troublesome to breed in captivity.
10. Giant Sloths-As far as I know sloths were solitary, so they would not be good domesticates.