Human beings born (and in typical usage, raised) on Mars. Due to generations of living under the conditions of a terraformed extraterrestrial world, Martians adapted to their home world and exhibit a number of notable differences from humans born and raised on earth.
There is some debate as to whether to consider Martians of sub-species of homo sapiens, as there are both genetic and epigenetic differences between Martians and earth-born humans. However, opponents of the sub-species view argue that the differences found in Martians do not represent a development of new features, but rather a loss of features due to a low founder population.
Notable Differences[]
At birth, Martians tend to be smaller and lighter than humans born on earth, and they have a lower bone and muscle density. As a result, they are more prone to injury outside of the Martian environment (such as during space flight or on visits to earth). The lower gravity of Mars leads to most Martians growing significantly taller than their earth-born counterparts naturally would, and the average height for Martians males is around 6.5 feet.
About 95% of Martians suffer from a condition in which their eyes produce a mutated form of melanin, causing them to have dark-blue, hazel or green, or purple-ish eyes. Though their vision is not usually affected, most are required to wear protective contacts or sunglasses to shield them from the sun's rays and strong sources of light, even at night.
Due to growing under decreased gravity, Martians who do not regularly train under artificially increased gravity can suffer from severe gravity-induced problems when travelling on spaceships or visiting other worlds with stronger gravity, usually stemming from decreased blood-flow to the brain, which can induce light-headedness, blackouts, vomiting, and weakness.
Their hearts are weaker than those of the average earth-born human, and so most Martians are given supplements, steroids, and even special suits to compensate and help their bodies to grow normally.