The seawater out there is a freezing minus four degrees, but these swimmers are splashing around at a balmy 19.

那里的海水有零下 4 度，的温度，但这些游泳者却在温暖的 19 度海水中戏。

Such low energy content in our bodies just isn't worth the effort for a shark, and that's why many swimmers splash in waters every single day that are infested with sharks, and are none the wiser for it.

我们身体中如此低的能于鲨鱼来说不值得的，这就为什么许多游泳者每天都在鲨鱼出没的水域中戏， 并且此一无所知。