This is a question that my girlfriend, being a lifeguard, posed – there are bite marks in every single float, both the little ones that you learn to swim with, and the big “fun” ones, at the swimming pool where she works.This can’t be due to under-nourishment, surely, so is there another reason?

You see these on ships, and even at pools. They are donut-shaped and made of light foam to make them float. They might be wound with rope and many times they have writing on them to indicate its location or ship. What are these things called?