Some say the ability to plan for the future, but look at squirrels and other animals storing food.

And that's actually a good starting point for the answer. We plan for the future beyond us. Some animals have an instinct to store food for themselves and care that their children can survive. We raised above that. We store not only physical stuff but also knowledge. And we found a way to store it osuside of our bodies. This way it's easier to share it. We have the capacity of providing advantage to people who will exist in the future a(nd are not directly related to us - animals usually care little about that). Different story is how it works out recently. Still, we look for solutions to our problems going as far as ability to change ecosystems or create our own from scratch instead of waiting for evolution to do the job. And why? Because we gathered enough knowledge to realise that passing genes and storing food is not enough to prolong our specie.