along time ago a group Australopithecus somehow manged to get washed ashore on let's say the Antarctic peninsula or at least an island near Antarctica now inhabiting mainland Antarctica and evolving human level intelligence. the question i want to know is what adaptations would a hominid need to survive in mainland Antarctica?
Antarctica does not support much of vegetation. So your diet would be "protein with lots of fat" alternating with "fat with some protein". Your hominid would badly need to evolve a digestive system that is better at handling a diet like this.
It would essentially become a hypercarnivore. Probably with teeth and jaws to match.
Losing your extremities to frost bite sucks. Fingers, toes, nose, ears and face would need to adapt. Thicker and blunter shapes. More blubber under the skin. More hair.
I think a layer of extra fat under the skin and a layer of short and dense hair on it would be reasonable. Longer hairs to keep off wind would also be nice since it would reduce need to rely on clothes.
Part of the year the day is very long and night short. Part of the year the day is short and the night very long. You'd want to sleep very little part of the year and sleep very much the other part. You'd also want to eat very much and very little depending on season.
And the really weird part is that if we look at polar bears, the Arctic hypercarnivore, the time they hunt is actually winter because that is when there is sea ice and their prey is not off at sea swimming around faster than a bear or hominid can match. So the activity cycles would not match the amount of daylight.
So I guess what you'd want would be adaptable activity cycles with ability to stay awake when you want and to sleep for a long times when you do not. Better night vision would be nice as well. Maybe better sense of smell to find prey in the dark.
A lots of body fat to balance the variations in food supply and the need to survive without food. Hominids would probably have the advantage in ability to store food though.
And tool making would give superior adaptability. You could hunt in the winter and fish during the summer. And since you can use thrown weapons or slings to hunt birds and can dig to access fish under the sea ice, you'd eventually get ability to do both off-season to some extent and stabilize food supply.
Larger animals retain heat better so they'd simply increase in size. This would be further boosted by added fat and fur. And as mentioned the effect would be amplified for extremities being blunter and more massive.
The largest land animals in Antarctica are penguins and seals.
If a hominid needs to survive on its own there, it has to adapt like they did, thus:
- develop fat layers for insulation
- adapt to an aquatic life style for gathering food
- use dry land only for resting and mating
As you see all of the above require living in proximity to the sea, since it's the only place where one can find food. Mainland is just snow, ice and rocks. No way to survive on them.
The main adaption they would need is intelligence. If this Hominid species evolved into something as intelligent as Homo sapiens then they would be able to survive on the coast of Antarctica in much the same way as the Inuit survive in the far north of Greenland and Canada.
Fish, penguins, seals and sea bird eggs would provide sufficient nutrition and habitation could be provided in corbel built rock shelters such as those seen in Skellig-michael in Eire. This could be supplemented with igloos on the sea ice during hunting expeditions.