Woah, woah. Hold on, I found something.

;^)

To my knowledge and correct me if I am wrong why would they put the species in teaser trailer the horses that is if they weren't going to make them playable?

To be honest if they don't have plans to make them playable it's something to think about since horses tend to be a pretty big boost to popularity with games don't know what it is about the giant grazers but it seems to benefit games more by having them as mounts or playable than it does to not have them playable at all.  Plus why tease it if they aren't making em playable XD seems pointless to tease them along with other playable species if you aren't making playable. Just some food for thought is all.

Eutheria is an animal clade, isn't it? It includes anything that is a mammal and isn't a marsupial or a monotreme I believe

That is vague indeed xD

But yes, horses will definitely be playable!

I believe we might also be getting deer? (don't quote me on that but I could have sworn I saw that somewhere)

I am very curious about that 'shadow deer' from the trailer.... It would be neat to be able to play as something like that, but I have a feeling it's a god or something. Hopefully CS will add deer, it would be nice to be able to play as prey and not predator