These acorn worms have a head for swimming
Putting off trunk development may make catching prey easier, researchers say
![acorn worm larvae](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2017/01/121516_ED_swimming-heads_main.jpg?fit=860%2C460&ssl=1)
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