Lessons from Planaria: Persistence in Science and Life

In my 1960s college days, I was lucky enough to observe live flatworms (planaria) under microscopes. They are incredibly cute, with two big eyes on the tops of their triangular heads, and a thrashing tail behind them. I particularly loved putting obstacles in their path. With no apparent distress, they simply backed up, changed angles, and charged ahead—repeatedly. Eventually, they came to the end of the obstacle or an opening in it and were able to move freely on the microscope slide.

Life was hard for me in the 1960s, full of obstacles. Career-wise, my best option was teaching. I had little interest in teaching. Teacher training in the 1960s was either a harbor for avoiding the Viet Nam draft (if male), or waiting rooms for females looking for an educated husband and a career with hours conducive to child-raising (as no other career was). The more wealthy students could pursue graduate degrees and become expert in something; I was lucky to graduate with an undergraduate degree (with loans and my husband’s help), so that was not an option. I was denied entry to the business school at my college, with the explanation that “Girls don’t succeed here.” The mindless little planaria became my hero with his/her persistence.

In the 1960s, research which is now questioned indicated that planaria could be trained to go through mazes, and then fed to other planaria. The cannibalistic planaria were more quickly able to progress through the same mazes! Learning via cannibalism! How exotic and exciting was that, as I droned through memorization after memorization. But my job as a biology teacher (made more difficult because I wasn’t a coach, as most biology teachers were), marriage and parenthood distracted me from the joy of sifting through stagnant ponds to search for planaria to watch.

But science and planaria moved on. Even more exciting to scientists was that planaria could regenerate. A 2013 study dusted off the studies of 50 years ago, and showed that trained, decapitated planarians exhibit evidence of memory retrieval after regenerating a new head. (Try not to visualize that; it’s disgusting!)

Now my charming two-eyed planaria is a biological hero. A 2025 study in Cell Reports trumpeted that  “there must exist a mechanism for stem cells to process multiple independent signals and ensure faithful regeneration outcomes in planarians…this regulation paradigm could be relevant to other species, even without whole-body regeneration.” Moving on, it is now believed that planaria never age; they just regenerate. (For the scientists, this is related to a shortage of telomeres.)

The moral of this little tale? In addition to the impact of this microscopic being on my personal life so long ago, this simple creature has gone on to promise understanding and cures for everything from blood diseases to lost limbs. Another moral is that published science is not ever lost; even 50 years of skepticism can be undone and put to human advantage. The discarded ideas of today may become important tomorrow. Ironically, it took a similar 50 years before I was given a responsible top-level business job. 

Maybe my descendants will someday be able to pursue exotic non-cannibalistic research to benefit humanity, or engage in leadership despite the skepticism of their colleagues. Doesn’t that make you optimistic?  Persistent?