I don’t know if this could ever be a pet, but it sure sounds cool. It is the only surviving species of a 4th type of reptile (the other three being crocodiles, snakes & lizards, and turtles and tortoises). Read up on the Tuatara, it’s got lots of neat attributes: the remnant of a third eye, special teeth where one row slides between two others, no external sex organs, and a whole lot more. They might live to be 200 years old! And it may be the oldest creature around.
