Scientists Observe a Ram’s Horn Squid

The ram’s horn squid’s unique shell often washes ashore on beaches, but before now, scientists had never seen a living individual. While surveying deep sea regions of the Great Barrier Reef, the Schmidt Ocean Institute’s remotely operated vehicle SuBastian captured video of the squid about 2,790 feet below the surface. While most living squids have an internal hard-shell remnant known as a pen, the ram’s horn squid has an internal shell shaped more like the external, coiled shell of its cousin the nautilus. The squid swam with its head facing up toward the ocean’s surface, the complete opposite of how scientists believed the animal moved. Often, a shell is used as a floatation device atop the body. The chambered shell works like a submarine’s ballast system, with fluid and gas passing between chambers to adjust internal shell pressure as depth changes. The ram’s horn squid’s perplexing reversal of convention is fitting for an animal that has avoided detection until now, and scientists hope to learn more about how it is able to swim with such a body structure.