The nautilus

Living fossil, unchanged for 360 million years, the macromphalus nautilus, cephalopod is endemic to New Caledonia.

The Cephalopodan class includes the most advanced molluscs. Nautilus is the last representative of Tetrabranchiata cephalopods, that almost all disappeared from the seas of the planet in Cretaceous, 60 million years ago.
The nautilus is found on the outer slopes of the barrier reefs at depths of about 600 meters. It floats usually in mid water and near the bottom. The diver could follow it without difficulty because it moves slowly "backwards" using its nozzle, a sort of funnel-shaped rudder, placed on its tentacles. He can pulsate through the water in all directions, moving upward, downward or sideways. The eyes are undeveloped. He cannot tolerate temperatures above 24 ° C and does not like the light. Its natural life does not seem to exceed 6 years.

Its main predator is the octopus. It is common to find shells on the islets’ beaches around the great reef and the Iles Loyauté (Loyalty Islands).

Its shell, an architectural marvel is a perfect logarithmic spiral consisting of 30 chambers, allowing the regulation of its buoyancy, of which the animal occupies only the last one. The nautilus has a slightly negative buoyancy, so if it stands still it slowly sinks.
The Aquarium of Noumea has presented the first nautilus that could be observed in captivity. The Toba Aquarium in Japan, associated with that of Noumea, was the first to breed successfully in captivity a baby nautilus from a Caledonian "mom".