Technically, it's ALL colours! Whites-only? Hmmmm..... I see shades of supremacy here; watch out Toronto Zoo, you don't know what a can of whup-boiled potatoes/snow peas you are messing with here!
What the heck? It's sold out? Well, I guess they only make so many whitey crayons... This is either a funny in-joke or some cruel, child-hater slipped one past the boys in marketing.