I’ve been spending a lot of my free time outdoors recently; I frequent the rivers, lakes and hiking trails. One thing I’ve noticed is how often people throw rocks into rivers and lakes. Even the youngest children instinctively do this. It does make me wonder if, given enough time, those bodies of water will become shallower and wider. After all, nobody goes in after them and puts the rocks back.
This behavior seems so universal that there must be an evolutionary explanation for it.
Perhaps our ancestors needed to probe bodies of water before crossing them or drinking from them. Throwing rocks in the water would help reveal dangers such as crocodiles or piranha.
Similarly I got to thinking about how my cat paws the floor in front of her water bowl (and the bowl itself) before drinking.
I’ve always assumed this is because her distant ancestors used to sometimes have to dig for water, or clear away vegetation, insects etc. to get to clean water. The Daily Cat has another explanation:
The Bowl Prober
Bowl probers sometimes paw their water bowls before they drink. The reason: it’s following the pattern of “wild cat ancestors who need to test the water to make sure it is safe,” says Moore. Cats’ paw pads constitute one of their most sensitive areas so, “Pawing the water helps some indoor cats check for any possible ‘dangers’ lurking in the water bowl.”