Re: Human curiosity
We aren't the only species doing that. Not a stone but one summer I was sitting at the lights at a local intersection here in Dundee and on the grass verge beside me was a crow which was moving along a line of pats of grass clippings, flipping them over, cocking its head then darting in for a morsel.
Various invertebrates were sheltering in the relative cool moistness under the pats of clippings. It was hot and sunny* and the cut grass was browning.
Just think about the cognition to recognise that as a strategy and that one might not be a fluke. Crows are SMART. Remember the New Caledonian variety is a toolmaker. Ours can often be seen working the strandline on the beach.
*Yes really, Dundee is the sunniest city in Scotland. Clouds approaching from the West are often caught by the hills to our north opening the skies over the city. This fact irks St Andrews a bit since they have fractionally more sunshine hours than us but since they recently rejected the opportunity to become a city, retaining their Royal Borough status (dating from before the Union of Crowns btw) so tough cheese.