How Bizarre Animals

These acorn worms have a head for swimming

Putting off trunk development may make catching prey easier, researchers say

acorn worm larvae

GETTING A HEADSTART  This marine acorn worm spends its larval phase as essentially a “swimming head” (left) before metamorphosing into a juvenile (middle), according to new genetic analyses. Adult worms (right) can grow up to about 40 centimeters.

Paul Gonzalez/Stanford University (larva), Chris Patton/Stanford University

By Emily DeMarco

- More than 2 years ago

Certain marine worms spend their larval phase as little more than a tiny, transparent “swimming head.”