12. Tuatara
The tuatara, Sphenodon punctatus, is an ancient reptile native to New Zealand, renowned for its remarkable adaptation to cooler environments. Unlike most reptiles, which are ectothermic and thrive in warmer temperatures, tuatara can remain active at temperatures as low as 5°C (41°F), a trait rarely seen outside their lineage. (nzgeo.com) This cold tolerance is facilitated by their low metabolic rate, allowing them to function effectively in the temperate climate of New Zealand. (en.wikipedia.org)