THERE are several characteristics that are generally associated with each class of animal - birds have beaks and talons, or webbed feet, reptiles have scales, mammals usually have fur and give birth, and so on.
Most definitely in a class of its own, platypuses are mammals that lay eggs, have beaks and have webbed feet. There are other cool characteristics about platypuses but one in particular sticks out and tips the unique scale a little more.
