Santa Claus is actually a Garden Gnome. For generations people have asked how it is possible that Santa Clause could climb down a chimney without getting stuck. Now we know. Santa is a Garden Gnome! It just makes sense. Garden Gnomes live almost forever and have tremendous strength and can easily fit and climb down a chimney.
This would also explain why small children who have sighted Santa describe similar descriptions. Santa is small, but to children he is big. Now you know.