Why Do These Fossil Shells Flip Their Spirals Every Few Millennia?

Foraminifera, or forams, are single-celled marine organisms found in all oceans, from tropical to high-latitude regions.

They are among the most abundant eukaryotic organisms on Earth.

Forams secrete a hard shell with many small holes, often coiled in a spiral like a snail.

Most species live on the seafloor, while others float in ocean currents as plankton.

When they die, their shells accumulate on the seafloor, creating a natural record of Earth’s history spanning 560 million years.

Scientists study these shells to reconstruct past climates and ocean conditions by analyzing species composition, isotopes, or trace elements.

Some foram species exhibit a strong preference for coiling their shells either left or right, with up to 97% of individuals in a species showing the same coiling direction.