Fossil shell of a nautilus
The nautilus is a living fossil. The animal has existed in almost unaltered form for 500 million years. 200 million years ago were the heyday of the nautilus when numerous species appeared all over the world. Today six more species are known that 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 an insight into the structure of the chambers, each time a large chamber is built during the growth of the animal that 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 through the water with its tentacles. These specimens were found in Madagascar and are hundreds of millions of years old.