their path也是可以的啊,their并不是复数的标志啊,他们的path可以是他们共同的一个path,也有可能是他们不同的多个path,所以their path不能split,OG上有很清楚的解答,while individual Neanderthals may well have followed different paths, this sentence is about the single evolutionary path taken by Neanderthals as a species.