Within their shells, they had a number of chambers, called septa, filled with gas or fluid that were interconnected by a wee air tube.
By pushing air in or out, they were able to control their buoyancy in the water column. These little cuties were predators who hunted in Cretaceous seas.
They lived in the last chamber of their shells, continuously building new shell material as they grew. As each new chamber was added, the squid-like body of the ammonite would move down to occupy the final outside chamber.
Not all ammonites have this whacky corkscrew design. Most are coiled and some are even shaped like massive paperclips. This one is so remarkable, so joyously perfect my internal thesaurus can’t keep up.
