Great article! I just want to add one little addition.... I know you were speaking about mammels only, yet fowl have hair also!
Feathers (hackle) for all fowl, are also hair. The main stem from which all the barbs protrude from, give the birds protection from the climate changes and ultraviolet rays from the Sun, helping the birds to maintain their body internal body temperture from extreme hot and cold temperatures, are also considered as hair. ~Parnelli
"Everyone you meet in life, give you happiness! Some by their arrival, others by their departure!" ~Parnelli