I believe that they do,and at very high rates but they get run over by cars much more frequently. I think that neither really makes them less 'immortal' in the

I believe that they do,and at very high rates but they get run over by cars much more frequently. I think that neither really makes them less 'immortal' in the sense that this article means. Though I can see the argument that errors in cell replication leading to cancerous growths could be counted as a form of natural life span limitation, I would be surprised if it didn't also happen to this jellyfish.