system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do we get goosebumps when listening to music that moves us.
gpt
Goosebumps are an evolutionary vestige from a time when we had fur. When hairy mammals experience events or stimuli such as mating, competition or defense (adrenaline spikes), the skin pores that hold hairs stand more upright making animals appear larger. Cold weather also triggers this response, the hairs stand more upright capturing more air in between each hair creating a natural insulation like a parka jacket.