What is a nautilus?
A nautilus is a type of cephalopod, a cousin of octopuses and squids. Nautiluses today look very much like their ancestors found in fossils from millions of years ago. Some people call the nautilus a “living fossil.”
The nautilus is sometimes called a chambered nautilus because it has a shell made up of separate chambers. The nautilus adjusts the amount of liquid and gas in its shell chambers to control its buoyancy. The buoyancy of the nautilus is how it floats in the ocean. When the nautilus’s shell chambers fill with water, it goes down. When it removes water from the chambers it increases its buoyancy and floats up.
The chambered shell of the nautilus prevents it from going below 800 meters (2600 feet). Below that depth, the pressure of the ocean would crush the nautilus shell and kill it.
Famous but still mysterious!
Nautiluses live in tropical seas around Indonesia and Australia. They are famous for their spiral-shaped chambered shells. Over the centuries, nautilus shells have inspired math, poetry, jewelry and paintings. The word “nautilus” has been used to name ships, luxury watch collections, exercise machines, and even a deep-sea mining company.
Despite being well-known for their shells, relatively little is known about nautilus ecology and conservation. People are not even sure how many species of nautilus there are.
Conservation biologist Gregory Barord studies nautiluses. He explains: “If you compare them to the octopus, the amount of information we know about them is virtually nothing.”
Scientists find and describe three new species of nautilus
In early 2023 Gregory Barord and his colleagues described three new species of nautiluses from the Coral Sea and the South Pacific. The scientists used genetics, geographic locations, shell size and coloration to describe the new species.
How to safely trap and study a nautilus
To find the new species, the scientists traveled to Fiji, American Samoa and Vanuatu, all island chains in the South Pacific. They built large traps out of steel, mesh and chicken wire. They then baited the traps with raw meat (usually chicken). At dusk, they dropped the traps to a depth of 300 m (980 ft) underwater. When they retrieved them the next morning, the traps would be filled with nautiluses.
Previous researchers killed nautiluses to study them, but Barord and his team kept them alive instead. The placed the nautiluses in chilled seawater to keep them comfortable. When they returned them to the water, they did something called “nautilus burping,” which involves swimming or scuba diving with them for about 30 m (100 ft) to ensure they don’t have air bubbles trapped in their shells and that they can safely get back to their deep-sea habitat.
The newly described nautilus species are separated from each other by deep water that nautiluses can’t safely travel through. Deep water likely acts as a barrier that separates nautilus populations. Over time populations evolve into different species. There may be several other species of nautiluses waiting to be observed and described!
This story was adapted for Mongabay Kids. It is based on an article by Elizabeth Claire Alberts, published on Mongabay.com:
There are several threats to nautilus populations, including the trade in nautilus shells, pollution and climate change. Learn more about these threats and conservation action you can take by visiting the resources below.
Smithsonian Ocean: A detailed resources on cephalopods
Smithsonian Ocean: How big are the cephalopods?
Save the Nautilus: conservation organization
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