Hm, that's a tough one. Considering the last two posts, I think it's tough to say the degree of their intelligence and sapience. If they truly tamed a bearyena, then that would be a strong indicator. If it was merely a symbiotic relationship, then that doesn't necessarily prove much. However, since the game uses the term "tame", my assumption would be that the niche critters are capable of taming.
Another thing that suggests a higher level of thinking is their adaptability. While many species are adaptable do different environments, nichelings can adapt their behaviors as well. For example, they will stay close together in the cold, team up to hunt prey, stay away from each other if sick, and behave differently to younger and older bearyenas. These are all things that an individual species may do, but like betwixted said the more of these traits you put together, the more likely that the species is displaying some level of higher thinking. Adapting behavior rather than physically is a huge part, from my observations, is what makes an intelligent species "smart". Most of my examples I have listed could also be attributed to instinct, but I do think they support my case nonetheless.
To conclude, I think that there really isn't enough information to make a strong decision either way. Which begs the question, if these creatures existed in real life, what experiments would we do to determine their intelligence?