Brooklyn College Researchers Uncover the Nautilus’s Memory

An ancient “living fossil,” whose family tree contains octopuses, cuttlefish, and squid, has been shown to possess both short- and long-term memory even though it lacks the dedicated brain regions for learning and memory that other cephalopods have, two Brooklyn College researchers have discovered.

Associate Professor of Biology Jennifer Basil and Robyn Crook, who recently finished her Ph.D. at the College, had their work reported in Nature, an international weekly journal of science. Nature highlights the results of their two-year study of the behavior of the more than 300,000,000-year-old Nautilus pompilius, sometimes called the “chambered nautilus” because of its multichambered spiral shell.

The dozen Nautiluses that were the subjects of the Brooklyn College scholars’ study were trained to learn to associate the smell of fish predicted by a flashing blue light. Evidence of this learned association was that the animals extended their tentacles, expecting the fish odor, in response to nothing more than a single flash of blue light.

The scientists also found that the nautiluses could remember their training for up to twenty-four hours and that their recall within the first hour proved as good as that of other cephalopods with much more complex neuroanatomies.

Previously, they explained, “people apparently just assumed that because nautiluses had been around for so long without changing that they lacked the ability to learn or remember.”

“When we first began our observations of the Nautiluses we only recognized two behaviors,” said Crook. “These were ventilating and extending their tentacles.”

Nautiluses, which inhabit the waters of the Indian and southwestern Pacific oceans, have roughly 90 tentacles that they use to catch food. The animals travel up and down from seven hundred meters below sea level to seventy meters below the surface in their search for food.

“They are primarily scavengers,” said Basil, “but you have to be careful when handling them. A friend of mine had part of her fingertip bitten off by one of them.”

In the wild, nautiluses can live for approximately twenty years, the scientists said. “They typically take ten years to mature,” said Crook, “and their eggs take nearly one year to gestate.”

Despite the fact that they live their entire lives in almost total darkness, the animals do have eyes, although they lack lenses.

Yet, “their relative, the octopus, has very good eyesight,” noted Basil. “We believe that olfaction, the sense of smell, is the primary way that nautiluses find their food.”

“Unlike octopuses or squid,” said Crook, “nautiluses have no suckers on their tentacles.”

The Nautilus’s tentacles are covered with a sticky substance, she said.

The animals used in the women’s study were kept in two 190-liter tanks of salt water in the Aquatic Research and Environmental Assessment Center at Brooklyn College.

“We were both interested in studying learning and cognition,” said Basil, who worked at the Marine Biological Laboratory in Wood’s Hole, Massachusetts, before joining the Brooklyn College faculty.

Nautiluses are very ancient creatures. Evidence of their existence has been found as far back as 300 million years ago.

Previously, said the scientists, people apparently just assumed that because nautiluses had been around for so long without changing that they lacked the ability to learn or remember.

“The fact that the work of these two scientists has been published shows that there is widespread interest in this area involving learning and cognition,” said Professor Peter Lipke, chair of the Brooklyn College Biology Department.