When you think about it, the shape of a heart in nature is, well, somewhat rare. You might see it in cloud, or an old tree, or somewhere occurring naturally in nature.
So, when you see it, you think "Oh, that's sort of cool", right?
Well, in animals the heart shape can occur naturally, as in the above.
In the design of the fur.
I've been able to collect several pics of cats which have heart shapes in their coats. Take a look.
I saved this until the weekend of Valentines Day...
So, Happy Valentines from me!