Answer: The spiral shells of the Ramshorn Squid look much like a Nautilus. For good reason. The Squid and Nautilus are relatives. The shell of the Ramshorn Squid, or Spirula, is hidden within its body and used to regulate buoyancy by changing the amount of liquid in the tiny chambers within the coil.

Spirula live in deep water, down to 200-600 meters. At that depth, darkness rules the day and night. But, the little squids have a taillight--a tiny yellow-green light just between its two fins. Schools of squid may keep in touch with one another by watching the flashing lights of their neighbors as they move up and down in the depths.

Photo by Ron Hirschi from Spirula Collection of his cousin, Malacologist, Tom Rice. Spirula collected in West Thailand.

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