How Does the Tuatara Breed?

The tuatara, a unique reptile most closely related to lizards and snakes, is frequently called a "living dinosaur." This slow-growing animal breeds only rarely and under certain conditions. This, combined with predation by introduced species of rats have caused this animal, endemic to New Zealand to be endangered. Currently the tuatara can only be found on a few offshore islands and sanctuaries.

  1. What is a Tuatara?

    • To understand how the tuatara breeds, it is necessary to understand what it is. The tuatara is the only remaining member of order Sphenodontia, a reptile dating back to the Mesozoic Era. Its nearest living relatives are snakes and lizards, but evolutionarily, parts of its skeleton appears similar to fish. One of those similarities is the "cloaca" or "vent," a small hole through which animals of a number of different species urinate, excrete and mate.

    When Does the Tuatara Breed?

    • The long-lived tuatara, which can reach ages of 100 years or more, takes a similarly long time to reach sexual maturity -- between 15 and 20 years. However, once the female reaches this point that is not all she has to do. It can take as long as three years for her body to develop the egg's yolk, and after fertilization it can take up to nine months to form a shell. What this means for the tuatara is that males can mates every year but the females mate only once every four to seven years, depending on factors like food supply and quality. The tuatara prefers to mate in late summer or early fall and the eggs will go dormant, but not die, if temperatures drop too low.

    How the Tuatara Breeds

    • When the female tuatara is ready to breed, the males will begin their courtship. The male will approach her with darkened skin and will walk in circles around her with his crest raised. If she is not interested she will return to her burrow, otherwise she will let the male mount her. After lifting her tail, the male will place his cloaca over hers, passing his sperm into her. The female can take up to a year to develop eggs from this mating.

    Young

    • Once the female has finally developed her eggs, she will lay them in a pre-made hole stolen from a bird. The eggs will take between 11 and 16 months to hatch, with the animals gender decided by the surrounding temperature. This has caused some concern among scientists since females are born at lower temperatures, leading to fears that global warming could contribute to a disproportionate number of male tuatara.