Humans are a species from Earth, and are seen as valuable commodities to the Furons. Despite being almost insignificant compared to other alien species, all human beings are integrated with pure Furon DNA, making them the key to the survival of the Furon race.
Humans are bipedal primates with varying skin tones and hair colors, though some humans are bald. Most humans are unremarkable in comparison to other races, having no sort of natural defense measures like armor or psychokinesis. However, each human carries a strand of Furon DNA, since every human are descendants from Furons that came the Earth long ago.
The history of the human race is given in bits and pieces throughout the series. A number of Furons discovered Earth, mated with humans, and as a result led to humanity being endowed with Furon DNA.
Thousands of years passed as human society became more advanced. Humanity was rediscovered in the late 1950's, as a party consisting of Orthopox 13 and Cryptosporidium 137 went in search of harvesting Furon DNA. The Furons have infiltrated human society and since then, they have been collecting DNA by killing humans, one to few at a time, and extracting it from human brain stems.
Of course, some authorities and many human groups discover this and do their best to undermine their mission and take them down, but their feeble efforts were always no match for the Furons' superior abilities and intelligence.
Human technology is terribly archaic and inefficient, compared to the Furons. However, they employ a much more vast array of resources, but carbon combustion and electricity are the most commonly seen, however, humans have been able to develop nuclear power to compensate. Humans are new to space travel and their ships are quite slow.
Despite these disadvantages, human resourcefulness can still pose a major threat, their nuclear missiles can destroy a Furon Mothership.