Since early humans traveled from place to place and from climate to climate, they discovered the need for skins as protection from the cold.
Hunters might have first used animal skins in hunting to cover their scent or to disguise their appearance, thus allowing them to get closer to their game.
Skins might have also been used in religious ceremonies or in dances. If a man wore a lion’s skin in a ceremony or dance, he might have hoped that it would give him the strength of a lion when he went off on a hunt.
From these other various uses, early humans probably discovered the warmth of skins and their durability against hard wear.