10. Red Sea Urchins
Red sea urchins (*Mesocentrotus franciscanus*) are among the longest-lived animals on Earth, with lifespans exceeding 100 years and some individuals reaching over 200 years. (eurekalert.org) They exhibit negligible senescence, maintaining consistent reproductive capacity and bodily functions throughout their lives. (pubmed.ncbi.nlm.nih.gov) This remarkable longevity is attributed to their indeterminate growth, lifelong reproduction, and resistance to age-related decline, making them a subject of interest in aging research. (pubmed.ncbi.nlm.nih.gov)