Sloths... so you think they are slow moving, while they spend most of the time in trees they are actually really good swimmers - they can swim through water 3 times quicker than they can move on the ground! BBC.co.uk tells us that three-fingered soothers have two more neck vertebrae than any other mammal, allowing them to turn their heads through 270 degrees and effortlessly keep their nose above the water when swimming.