They could swam before they have been built, or to paraphrase Jeff Goldblum: "Life, err, finds a way". Are you one of those people who believe dams can protect you from bull sharks? Do you know why faucets have little mesh on the outlet? That's right! Tiny bull sharks could bite your fingers when you wash your hands.
this is primarily why marijuana is considered so dangerous. letting a pothead into your home will inevitably lead to them taking the aerator screens from your faucets to prevent hot ash from being inhaled during their pursuit of madness. in turn millions of minor finger injuries occur every year. spread awareness!
This is so good. I'm already halfway through the screenplay for "Baby Shark". The poster will have someone dangling their finger in water in a sink and a tiny bull shark coming up to bite it.