I never associated the Smurf with the Picts, but it makes sense. I always thought that their happy-critters-in-the-forest front was just a cover for something darker. Bright blue creatures wearing blinding white? Even in the Day-Glo forests of Peyo's cartoon world, that would stand out. I don't think I need mention that their dwellings, far from being camouflaged against predators, were gaily colored, in every sense.
Their heads were huge, yet their actual braincases looked pretty small. They had short, chubby arms and legs, and their feet were rounded on the bottom, hardly suitable for gaining purchase on the loose clutter of the forest floor. From a purely physical standpoint, the Smurfs were evolutionarily untenable.
They were reputedly vegetarian, though fond of pastries, but a vegetable diet provides less energy than one incorporating meat and animal fats. Even mice and squirrels, creatures of somewhat comparable size, supplement their vegetable diets with occasional invertebrates. Smurfs would have to eat constantly in order to maintain basic functions.
There are many other points which could be raised; I'm sure Lynne knows more about the biology of small animals than I. I have my own theory, though, to explain the Smurfs' viability.
Their happy-go-lucky demeanor was a clever ruse to hide their strictly-regimented, often cannibalistic society. Very few of the Smurfs, you'll note, had names; the rest were denied even this basic badge of individuality. They were merely parts of the greater tribe, to be used as needed, for defense, breeding, or even food. A central council of Smurfs -- led by Papa and Smurfette, the matriarchal iron fist of Smurf Village--controlled every aspect of Smurf life, keeping the plebes ignorant and placated.
Though well aware of the greatest threat to their survival--Gargamel--Papa Smurf and the rest of the azure hegemony did not seek to rid themselves of this threat. Rather, they merely neutralized whatever offenses were sent against them, keeping the central threat alive and scheming. Why? The truth is that Gargamel provided a focal point around which to rally the tribe; without a common enemy, rival elements could have arisen which would threaten the hegemony's grip on power.
Why would such obvious liabilities as Clumsy, Greedy, and Brainy Smurf have been allowed to live, if not to allow their foibles to endear them to the nameless mass of Smurf commoners? By letting the plebes think that the ruling class was "just like us", the hegemony let the common Smurf enslave himself.
In addition, alliances were pursued with influential humans (Prince Johann), while keeping the allies in the dark about the true nature of the tribe. Never were plebe Smurfs allowed to interact with outsiders; that was reserved for the hegemony, who had no incentive to end the facade.
These are just a few thoughts on what I term "the blue peril". Maybe one of these days I'll tell you what I think of Garfield.