questo senz'ombra di dubbio.. ma ti ripeto, non ci scommetterei ad escludere che non ci sia andata da sola.
in merito al principio di Archimede.. sai che la natura non smetterà mai di stupirci?
da qui: star tortoise in the water
da notare la didascalia:
saw this strange event in a water hole .two star tortoises were swimming in the water.when they become aware of my presence they withdrew their limbs in their shell,and started floating comfortably ,occasionally putting their necks out.but didnot try to dive.later my staff told me that these tortoises were actually trying to catch small frogs,and they have seen them doing so.