Acorn worms are our newest obsession

There are worm-like animals that create spirals on the seafloor, are more related to humans than actual worms, and produce super cute larvae?! We’re obsessed! 

Acorn worms are named for their front end that resembles the shape of an acorn.

Meet the acorn worm

Acorn worms belong to the phylum Hemichordata and class Enteropneusta. They’re named for their acorn-shaped front end. Check out MBARI’s Animals of the Deep video on acorn worms to learn how to pronounce “enteropneust.”

Acorn worms feed in a tight circular pattern on the seafloor.

Deep-sea enteropneusts roam the seafloor, consuming organic material mixed in the mud. In food-rich areas, they feed in a tight circular pattern. When an area is depleted, they empty their gut to become buoyant so they can float away to find more food.

Check out MBARI's Animals of the Deep to learn more about acorn worms! https://www.mbari.org/animal/acorn-worm/

September Badge ✨ Play Bound to find acorn worms and earn a special badge! Check your vault for more details. ✨

Keep an eye out for tornaria

Some acorn worms in the larval stage are called tornaria.

During a scuba dive off the coast of Kona, Hawai’i, researchers from MBARI’s Bioinspiration Lab encountered larval acorn worms, called tornaria. A tornaria larva looks like a tiny, transparent acorn or helmet floating in the water, and it has fuzzy bands of cilia wrapped around its body that help it move around and catch food. They eventually develop and grow up to become the acorn worms that we know and love.

Onwards and downwards!

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