The living fossil nautilus lives in the coastal waters of the western Pacific ocean, and has memory and learning skills roughly equal to a cuttlefish. It stays buoyant and propels itself forward with a gas-filled tube inside the shell and has 90 sucker-less tentacles protruding from the front of the shell.
The 20 centimetre (eight inch) shell of the chambered nautilus has up to 30 chambers that increase in size at the shell spirals outwards. As it grows, the nautilus inhabits the outermost chamber of its shell and begins to hunt crabs, fish and carrion that it comes across.
The nautilus relies on smell rather than sight as it’s eyes are primitive and simple. Its sense of smell is extremely well developed, which allows it to detect scents over 10 metres away (33 feet).
Image from www.flickr.com/photos/pacificklaus