Time captives could be all the memories a head can hold.
Every old man is a boy dressed in old man leather. Leather shows the times gone by, the extended hours in the sun, jokes told to wrinkle around the eyes, and sorrows borne to wrinkle around the brow.
If he’s been anywhere, he remembers it. If he left the cave at all, he logged that choice in instinctual remembrance so future generations would know to leave the cave. Every hunter was once a caveman. Every gatherer was once a cavewoman. No cave can keep a feral soul inside forever. Eventually the hunger will drive the wild things to explore, to hunt, to discover.
To go outside and smell the scent of adventure is sometimes all a belly needs. On the other occasions, when the instinct is total, the taste for flesh is all-consuming, compelling the natural creature to compete as a predator. The predator seeks out its prey.
Some wild ones rend the entire earth with teeth and nails. Others observe, watching for their turn on the carcass. Carrion lunch. Ribcage lunchbox.
Entire worlds of variety await the predator at the top of the food chain. Moments of panic, running, and hiding await the prey.
Man once arrogantly thought himself the top of the food chain. Then he met the crocodile, the shark, the lion. Mankind decided to buck instinct and return to the cave. Decorating the cave with lights and sounds, machines and screens, mankind got complacent, losing that feral edge. The species developed subspecies: the blogger, the tweeter, the troll. Soon these all forgot everything there was to know about outside. They craved it still. Their skins, the leathers of old men, became pasty, undernourished, without the touch of the sun, without the pressures of wind and rain. Then they knew, instinctively knew, they would have to revert to some of the old ways or consider mass extinction.
Then, one day, a thought came. Make the screens smaller. Take them along on the journey. Instead of preying on the field mouse, mankind could take photographs. Pictures of crocodiles prove a new sort of superiority. Digital capture, digital memory.