It looks exactly like a lizard, but it is not one. It has a literal third eye on top of its head, teeth fused permanently to its jawbone, no external ears, and a lifestyle so slow that a 111-year-old male recently became a first-time father. The tuatara is New Zealand's greatest reptilian survivor, and its existence forces us to rethink how survival works over millions of years.

This episode dives into the biology and conservation of the tuatara, the sole surviving species of an entire order of reptiles that thrived alongside the dinosaurs. We unpack its bizarre anatomy, its cold-adapted slow-motion metabolism, the genomic secrets behind its century-long lifespan, and the new climate threat that could doom it even behind predator-proof fences.

• It is the only survivor of the order Rhynchocephalia, a lineage that split off around 2 ...