Systemic species-wide genetic modification. Over the millennia, the Coluan genepool has been modified to extend the average Coluan lifespan to approximately 600 Terran years.

As children, we mature at a similar rate to Earthlings (albeit with much faster neurobiological development), but after reaching adulthood, we age very slowly and stay in our physical prime for centuries. It lends itself to a very youthful appearance that we retain through most of our lives.