Again Martians

"The Snows of Ganymede."

Guards on Ganymede:

"...had the gangling, bulge-chested slenderness which was also characteristic of Martians - low gravity, low air pressure even inside the settlements -..." (IV, p.155)

That sounds right for human colonists of Mars. There is a book about designing sf aliens. Unfortunately, I cannot remember either the title or the author's name but maybe someone else will. There is a section on the Star Trek tribbles. The book posed the question how to design native (not colonial) Martians and suggested the following line of argument:

a cold planet, therefore fur-covered inhabitants;

low gravity, therefore tall, thin bodies;

thin atmosphere, therefore large lungs and chests.

Then the book argued that that is a Terrestrial biped adapted to Mars, not an organism that has evolved on Mars. For the latter, we have to start again from scratch. But Anderson, of course, was describing colonials.