EXTINCTION OF TUATARAS WILL NOT BE OUR FAULT
The tuatara of New Zealand is a species on the verge of extinction.
Unlike with most other pending extinctions around the world, humans
are not to blame.
Tuataras look somewhat like iguanas that are brown instead of green
but differ from all lizards by having distinctive dental, skull, and
skeletal features. They also have blood cells that are larger than any
other living reptile. Tuataras have the remnants of a third eye in the
center of the skull, and although a similar structure has been studied
in some lizards, the function remains unknown. Another tuatara trait
also found in a few lizards is vocalization. Hearing a tuatara croak
on a cold, drizzly night on an uninhabited island a thousand miles from
Australia would presumably bring back some strange emotions related
to our own evolutionary past. They reportedly make a cricket-like sound
when picked up.
Tuataras reach lengths greater than two feet but eat mostly small animals, such as insects, snails, and frogs. They also eat bird eggs and a few small seabirds that nest on their islands. Tuataras are classified as endangered and are carefully protected. They cannot even be transported to zoos, and the few captives living in zoos today are often not on display. Most Americans have never seen a live one, and most New Zealanders have never seen one in the wild, as the islands themselves are practically inaccessible.
Tuataras have a long life span. One was kept as a captive for 77 years, and documentation that some individuals live more than a century would come as no surprise. Other age-related phenomena of importance are that these bizarre animals take up to two decades to reach maturity and more than half a century to attain full adult size. Female tuataras lay about a dozen eggs, but at intervals of four years. The eggs take as many as 15 months to hatch.
One of the greatest threats to the remaining tuataras are non-native rats that have been inadvertently introduced to the islands. A slow-growing reptile with a low reproductive output that has also evolved without natural predators can become dependent on extended longevity to assure successful reproduction. The presence of a new predator that can kill eggs, young, and possibly even adults could become a serious threat to the tuatara's continued existence. In fact, the sad news is that these unusual reptiles are already extinct on some of the islands invaded by rats.
Tuataras represent a conservation situation different from ones that pit economics against the environment or politicians against public sentiment. Humans protect today's tuataras as well as a wild animal can be protected. But all the species of tuataras have been on their way to extinction for millions of years, and the majority have already disappeared naturally.
Other species of wildlife and other environments have been woefully
neglected or actively mistreated by humans in many ways on a global
scale, but when the last tuatara dies, we really should not blame ourselves.