Hackles

TIL not all dogs have hackles (I think I probably knew that, since I never noticed them on my first Labrador), and that they can be considered a disqualifying condition for service dogs!

Ricki was released in the final phase of guide-dog training for having “hackles,” or a shark-fin-like fur on the ridge of her back that sticks up and can be seen as a sign of aggression. (Inside the World of Guide Dog Dropouts)

Hmm. Who knew? 

Normal mode Brian

Brian with hackles up