Kate Evans Profile picture
Nature writer & ocean journalist @NZGeographic also @Sciam @BBC_Future @bioGraphic. Fisheries, forests, fossils, plants, space. Working on a book about #feijoas

Jun 11, 2022, 11 tweets

I recently had the great pleasure of interviewing most of the people in the world who study #nautiluses, here are some of the amazing things I learned about these beautiful creatures. A 🧵 1/11 #WorldOceansDay

They haven't changed all that much in half a BILLION years. Their ancestors, the nautiloids, appeared 500 million years ago, and they evolved their distinctive coiled shape perhaps 100-200 million years ago. 2/

Most proto-nautiluses died 65 million years ago with the dinosaurs, but the deepwater ones survived -- scavengers sustained by the carnage above. As 'Professor Nautilus' Peter Ward from @UW told me, “What was left after the Cretaceous was over? Dead bodies.” 3/

The nautilus family tree is still being revised, but there are now around ten species in two genuses: Allonautilus (right) and Nautilus (left). Both live in the tropics, in the twilight zone between 100-800m below the surface. Below 800m their shells implode from the pressure. 4/

In Manus Island in PNG, nautiluses are called 'kalopeu', and their image adorns the flag of the Win Nation, a spiritual group led by the 'Melanesian Jesus.' Their shells are prized as a scoop for separating coconut oil from the starch in the cookpot. (Below, Chief Peter Kanawi)

They live for ages! Perhaps up to 30 years, and they don't mature until they're around 12 years old, meaning nautiluses are kids for ages! In the lab, they're apparently quite naughty, just like a gang of troublesome 12-year-olds.... 6/

...but they are super smart, definitely not 'dumb snails' as they've been uncharitably described. Like other cephalopods, they have excellent memory, can find their way through mazes, and maybe even have personalities. (No.9, apparently a "prince" among nautiluses, shown here) 7/

Whenever scientists put down traps in the tropical Pacific, 80 % of the nautiluses in the traps are male. This disparity was mystery until lab work revealed that female nautiluses avoid the scent of other females. researchgate.net/publication/26… 8/11

Noone has ever seen nautilus eggs in the wild. There's still so much we don't know about them, but they're under threat. Even though they are now CITES-listed, 1000s of their shells are still exported. In some places, like the Philippines, they are locally extinct. @gjbarord 9/11

The ocean is warming, and the twilight zone where they live is predicted to change the fastest. Nautiluses will have to move deeper, but there's only so far they can go before their shells implode, or they run out of reef. nature.com/articles/s4155… 10/11

Nautiluses survived Earth's last 5 big extinctions, including the 'Great Dying' 250mya. But can they survive us? “We’re worse than the Permian extinction,” says Jennifer Basil from @CUNY. For more, read my piece in @bioGraphic here: biographic.com/downward-spira… #SavetheNautilus 11/11

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