Sorry to be pedantic, but no, those people were called "Martians". (His term, "homo ares", is referring to Ares, the god also known as Mars.) The Belters live

Sorry to be pedantic, but no, those people were called "Martians". (His term, "homo ares", is referring to Ares, the god also known as Mars.) The Belters lived in the Asteroid Belt, and were opposed to both the Terrans and the Martians. The Belters were the most different biologically because the gravity is so low, whereas the Martians got to enjoy the relatively high 1/3 g gravity of Mars.