Biology

Humans are an endothermic species of omnivores, descended from arboreal primates. They have four limbs and exhibit bilateral symmetry – which is to say, they have two arms and two legs, one on either side of their body. They possess internal skeletons.

Humans are considered to reach physical and emotional maturity at 18, although it’s widely accepted that they still have much to learn after that point. Human lifespans can vary greatly; modern medicine means that humans generally live to be 100 years old and can make it as far as 150 years old without persistent mechanical assistance or genetic modification. With intervention they can live even longer, although their actual quality of life (and how far they may be considered “just” human) after that point is up for debate.

Individual humans can vary wildly from each other in many ways, from skin and hair colour to height and weight. There is one particular variation in human appearance which evolved during their confinement below the planet’s surface and at its extremes; these Polarised humans are marginally better adapted to cold, darkness and pressure. The physical indication of these traits are a grey colour to the cheeks and deep, dark eye sockets.