Wendy Constance's Brave was written a few years before Tarin of the Mammoths, and I think any similarities are pure coincidence -- but at times they did tread the same territory. Dangerous encounters with wild creatures, being swept away by a raging river, escape from hostile warriors, appeals to the nameless Spirits, all appear in both books.
Brave is aimed at a slightly older audience and contains a hint of romance. There's also a pretty high body count, which is realistic. I appreciated that the frequent hunting scenes glossed over the most gory aspects! But I think coming hot on the heels of Tarin, it was an overload of prehistoric adventure for this reader.