From Gineipaedia, the Legend of Galactic Heroes wiki
Humans, known taxonomically as Homo sapiens (Latin for "wise man" or "knowing man"), are the only-known sentient species in the galaxy. Humans evolved on the planet Earth roughly 200,000 years before the advent of the Common Era.
While no intelligent Extra-Terrestrial Life forms are known to exist in the Legend of Galactic Heroes setting, that does not necessarily mean that the galaxy is entirely devoid of alien life.
- Human beings depicted in LoGH appear identical to human beings of the modern day, exhibiting none of the adaptations expected to arise with the advent of space travel (decreased muscle mass, weaker bones, lack of skin pigmentation, etc.).