>>96217077
"Elves" are descended from something like homo erectus, so they're short and slender but physically powerful, with brow ridges and heavy jaws, attractive but clearly different from humans. Long ago the gods gave them near-immortality, and they've become very intelligent and sophisticated, but they remain hunter-gatherers who rarely live in fixed settlements.
"Dwarves" are essentially homo neanderthalensis, fond of cold climates such as you find in the far north or in high mountain ranges. They don't practice agriculture either, but they've become experts in a variety of crafts, so they hunt for their food and trade for what else they need.
"Halflings" are something like homo floresiensis, of course, a hominid species from one of the great equatorial island arcs, who went through a stage of insular dwarfism. Since being contacted by "elven" and "human" sailors, they've started to pop up all around the world, serving on board ships and then settling in small clans in major sea-ports. Not at all like Tolkien's hobbits.
"Orcs" are another Neanderthal-like subspecies (Denisovans?), also cold-climate-adapted, and shifted toward a fully carnivorous lifestyle. Instead of living in high mountains, they wander the open plains and tundra regions, hunting and herding and occasionally raiding the more sedentary peoples around them. They usually don't cooperate very well, but once in a while a great tribal chieftain pops up and leads them on some really big raids, and whole civilizations tend to collapse as a result.
Humans are the only ones who tend to go in for agriculture, cities, and elaborate political forms, but they're the least sophisticated of them all, if only because they're newcomers in the world. All the other peoples are watching humans with a great deal of amusement and suspicion, wondering what these fast-breeding brutes will do in the long run.
