The nautilus is a living fossil. The animal has existed in virtually unchanged form for 500 million years. 200 million years ago was the heyday of the nautilus when numerous species were found all over the world. Today, six more species are known to live in mainly tropical oceans.
Shell for protection
The nautilus is related to the squid and builds its shell for protection. These fossil shells are millions of years old and cut to give a glimpse into the structure of the chambers, with a large chamber being built as the creature grows and always lives in the latter.
The name comes from the Greek 'Nautilos' which means 'sailor' and probably has to do with the way the nautilus moves with its tentacles through the water. These specimens were found in Madagascar and are hundreds of millions of years old.