Ah, New Zealand. That dreamy cluster of islands that friends or maybe friends of friends of yours have burned up precious student loan dollars visiting during spring breaks and summer vacations. New Zealand has slowly drifted through millennia of isolation during which evolution ran amuck, creating a shocking array of birds and reptiles the likes of which we North Americans have only dreamed of through the months and months of cold winter nights alone — at least, this fine scribe has anyhow — but what I am really trying to write about is the ancient (and endangered) creature I hope to enthrall you with in this installment of zoological investigations: the tuatara.
Tuatara are reptiles, but not lizards. They belong to a related group, Sphenodontidae, which flourished during the Mesozoic period some 250 million years ago. Today, the only extant members of this group still in existence are the tuatara!
There are only two species, Sphenodon punctatus and S. guentheri, which once roamed gleefully throughout the North and South islands of New Zealand, but with the introduction of mammals, were wiped out on the mainland and now survive on just a handful of surrounding islands. With numbers as low as 400 adults, S. guentheri is currently facing extinction while S. punctatus is thought to boast only 50,000 individuals.
Some of the features which make the tuatara such an interesting animal to learn about are also contributing to their current decline. For example, tuatara can live 60-100 years and do not reach sexual maturity until 15-20 years of age. Males do not have a penis but transmit sperm to the female by positioning the opening of the reproductive and excretory tracts, the cloaca, close to that of the female (most birds do it this way, too, except turkeys — they’re crazy). Females become sexually receptive every 2-5 years (bum luck, huh?) and once their eggs are laid, no care is provided for the young. The eggs take between 11 and 16 months to hatch, which means there is a lot of time for things to go wrong!
Adults are nocturnal and feed on almost anything they can find, including invertebrates, eggs, birds and young tuatara! For this reason, juveniles are active during the day. Tuatara are found in close association with nesting shore birds because they inhabit burrows made by the birds and because their guano, or feces, attracts delicious insects. Perhaps the neatest thing about tuatara is their third eye! Unlike the yogis of the East, the third eye of the tuatara is visible below the skin on top of the head and contains a lens, retina and nerve connections to the pineal gland (which influences sleep and hibernation). The function of this organ is debated but some scientists believe it is used to regulate behaviours based on light and temperature signals.
If you would like to see a tuatara in your lifetime, you can fly to New Zealand for less than $2,000 CAD. Don’t ask me how you’re going to get home, though!