Good sleuthing, @Raenafel! That's how I knew Lionskin was female. The question is, are Woodshaver and Bristlebrush the same wolves that Nightfall and Scouter rode to Sorrow's End? We don't get their names until seven years later in the story during the quest, so it's possible they were born in the desert. My guess is quite likely they are the same, just given the age of the Nightfall and Scouter who are just slightly younger than Cutter. Woodshaver and Bristlebrush were likely their first wolf friends, and indeed, we see Scouter shedding a tear at Nightrunner's howl, with the caption saying that those Wolfriders who haven't lost their first wolf friend yet know that someday they must.