New player - skill question

I'm new to the game and there are some mechanics that confuse me.

At the moment, I'm trying to figure out skill progressions.

I'm playing Beorning, and so far have put all my trait points in the Red tree.

On hjitting level 12, I unlocked a Vigilant Roar trait, and I have no idea where it came from.

Google tells me it is from the Blue trait tree, but I haven't put any points into the blue tree.

Where did that skill come from?