Physical Changes in Future Humans

Recently I have read a number of stories that feature humans in or from the far future. How might such “Future Humans” differ from modern humans? Physical changes are likely to be the product of human engineering and technology rather than natural selection and evolution.
Before Genetic Engineering

Better Brains

Future Human is often depicted with an enlarged cranium to hold a larger brain. A larger head will increase the load on the neck and spine, so these will need modification to compensate.
Another problem is that larger heads will further complicate human childbirth. Even if technology such as exo-wombs are commonplace, it seems prudent for humanity to retain the capability for natural births without recourse to caesarean delivery.
Rather than becoming larger, a brain that is more efficient is more desirable. Technology rather than biology is likely to achieve this.
Following school, most people learn that you do not have to remember every fact and formula. Knowing something exists and where to look for it is usually sufficient.
Future Human will probably have something along the lines of the THS Virtual Interface Implant (VII). This will be their translator, navigator, calculator, library, clock and secretary.
The most welcome improvement to the human brain will be for it to become more resistant to degenerative conditions.


Future Humans are a little shorter than modern human males, averaging 1.7 metres. They are of a stocky build for better heat retention. Both of these traits help conserve resources. A modern man would find some of Future Human’s vehicles and quarters a little cramped.
A modern human might be surprised that Future Human females are of similar height to the males. Future Human males have less of a physical advantage over the females, many being their equal in strength. Larger female bodies are an advantage in pregnancy and childbirth.
Although similar in height and strength, males and females are still distinct. For easier childbirth, the female pelvis has been improved. Thus, females tend to have pear or hourglass body shapes, while males tend to be more rectangular or triangular.


Future Humans are often depicted as being hairless other than their eyelashes. A full head of hair has a number of advantages. It insulates against heat loss and sun. It helps sweat evaporate and reduces the likelihood of sweat running down the eyes. It also provides some protection against bumps and scalp cuts.
Future Human will probably cure baldness and have a good head of hair. For added protection, Future Human may choose to have dense, tightly curled hair that acts like a cushioning pad. Afros may come back into fashion!
Future Human males are usually shown as beardless. Preference for or against beards varies with era. Some strains of human already lack the capability for males to grow beards. It is therefore quite feasible that the trait for beard growth could be deleted. Alternately, as females more closely resemble males in size, beards might be welcomed as a means to distinguish between the sexes.
From the neck down, male and female Future Human will appear hairless. In actuality, their skin still has fine vellus hair. They no longer grow terminal, axial or pubic body hair. Perhaps a few rare males have vestigial chest or scrotal hair.
Vellus hair is blonde. Head hair may be white, black or any natural shade of brown, red, blonde or grey. Or dyed!

Better Eyes

Future Human eyes have undergone a number of improvements. Myopia, long-sightedness and astigmatism are virtually unknown. Most Future Humans have 6/4 hyperacute visual acuity.
Future Human’s eyes are also more sensitive at low light levels. This is useful on the outer worlds that receive less sunlight. On the inner worlds, it allows night-time illumination to be set at a lower level, conserving energy and resources. To a modern human, Future Human cities may seem dim at night. The reduced light pollution is a boon to wildlife and amateur astronomers, however.
Future Human’s more light-sensitive eyes are an inconvenience in very bright conditions. Rather than nictitating membrane biomods, the usual solution is simpler. Most Future Humans carry sunglasses.
Blue or grey eyes admit more light than darker pigmented eyes. Nearly all Future Humans have blue or light grey eyes.
Most Future Humans have an epicanthic fold, which helps shield the eyes from ultraviolet light.

Skin Colour

All Future Humans have brown skin. The pigmentation provides protection against ultraviolet light. Skin may tan darker or lighten, depending on exposure to UV.
Many of the major differences between Future Human and modern humans are internal.

Immune System

Civilization and exploration have exposed humans to many new hazards and threats. Reduced selection pressure made the species more vulnerable to disease.
Mankind applied its technology and knowledge to address this, and Future Human is a product of this.
Many hereditary medical conditions and genetic defects no longer exist. Allergies and auto-immune disorders are extremely rare.
In addition to their natural immune system, Future Human may have additional agents such as implants, biomods, nanosymbionts and a custom micro-biome. A minor, but useful, consequence of this is that conditions like body odour and bad breath are eliminated. This is welcome if you have to share a cramped space vessel or crowded city!
Future Human’s wounds heal quicker, their bones mend faster and illnesses are generally shorter. Future Humans do not experience loss of muscle-tone or bone-density under microgravity or zero gee conditions. See GURPS Bio-Tech 4e p.120 and p.165 for ideas on what nanosymbionts and custom biome can achieve.


It seems unlikely that the human digestive system will get much more efficient. A more efficient digestive system may be good for an organism, but not for the ecology it occupies.
How Future Human’s digestive system differs from modern human’s is in the greater variety of foods that it can utilize. Future Human’s biome provides their digestive system with various cellulases and chitinases.
The presence of the latter reflects that Future Human’a diet includes significant amounts of fungi and insects. Locust swarms are now harvested rather than poisoned.
The ability to digest cellulose allows materials such as cotton waste, unhusked grain or scrap paper to be processed into foods. A modern human is likely to find many of Future Man’s rations difficult to stomach! Future Human, on the other hand, regards a paper cup and packaging as part of the meal.

Water Use

Animals such as the kangaroo rat show that mammalian kidneys have the potential to operate more efficiently than those of modern humans.
Future Human has kidneys that are significantly more efficient than those of modern humans. When necessary, Future Human can survive on low rations of water. This is useful on long space voyages. Future Human’s enhanced immune system allows them to safely drink from water sources that would be hazardous to a modern human.
“They took away your scent. No enemy could smell you out. They gave you an epicanthic fold to protect your eyes. The flat, wide nose is less vulnerable and pulls in more air.”
He pushed his fingers into her hair. Spongy, resilient, thick. She didn't flinch; she smiled in pleasure.
“And this kind of hair to protect your skulls. It'd take an impact. You grow your own skewball helmets!”
“Brenda” by Larry Niven.