Shoshone's Pathfinder upgrade to what?

[Henri Christophe]

I was playing against Shoshone civilization in a domination strategy, in this game, the Shoshone was one of the last civilizations I invaded (in a small map) so they are around the renascence age and have a lot of musketman, and I look they and saw promotions as Survivalism I (http://www.dndjunkie.com/civilopedia/PROMOTION_SURVIVALISM_1.aspx)
As I know only scouts and Pathfinders are able to have this promotion, and both just can upgrade to archer or composite bowman according to http://civilization.wikia.com.

SO I WANT TO ASK! Is that an error? A kind of bonus for Shoshone when they controlled by AI? Because if have some way to have Musketman with Survivalism I, II and III. I will just use Shoshone to dominations games {By the way, I don't know if matters, but was a Deity game}

 

[reddishrecue]

Shoshone only get their pathfinders upgraded to composite bowmen. When upgraded, they get to keep the survivalism ranks that the unit received when it was a pathfinder. The ai probably had more promotions from the barracks, armory etc. either that or Deity difficult level which spoils AIs more than the human.