The Surprising Way Jellyfish Put Themselves Back Together
The moon jellyfish has a leg up on Humpty Dumpty—if it loses an arm, the ocean dweller can repair itself in a newly discovered process.
In the spring of 2013, biologist Michael Abrams had cut two arms off a young jellyfish when he witnessed something he'd never seen before.
"He started yelling... 'You won't believe this, you've got to come here and see what's happening,'" recalls his Ph.D. advisor Lea Goentoro, a biologist at Caltech in Pasadena.
The team expected that Abrams' moon jellyfish (Aurelia aurita) had regrown its limbs, since many other marine invertebrates—including the polyp stage of moon jellyfish—regenerate themselves this way. (See "Pictures: 5 Animals That Regrow Body Parts.")
Instead, the moon jelly had rearranged its six remaining arms until they were evenly placed around the body. Muscles in the jellyfish's body had pushed and pulled on the remaining arms until they