Ancient Reptile Clinging to Survival

[dcwsb inline="true"]

Zoo InternQuest is a seven-week career exploration program for San Diego County high school juniors and seniors.  Students have the unique opportunity to meet professionals working for the San Diego Zoo, Safari Park, and Institute for Conservation Research, learn about jobs, and then blog about their experience online.  Follow their adventure here!

There are over 1400 species of reptiles in the San Diego Zoo. Have you ever wondered why you never see this many reptiles? Only small portions of the reptiles are on exhibit, the rest are in the animal ambassador (animals dedicated for educational purposes) or breeding programs. This week as an intern, I learned more about one of these non-visible treasures in the breeding program at the San Diego Zoo, the Brother’s Island tuatara.

The Brother’s Island tuatara is one of the world’s most unique species because they are in their own order in the reptile class, of the animal kingdom. There are two species of tuataras, guntheri (Brother’s Island) and punctatus (common). Tuatara’s are classified in their own order, separate from lizards, due to their unique skull formation and their lineage. The tuatara is sometimes called a “living fossil.” Its nearest relatives are an extinct group of reptiles that lived over 65 million years ago with the dinosaurs.

These inhabitants of New Zealand are listed as an endangered species, according to the International Union for Conservation of Nature (IUCN). This is due to habitat destruction, but mostly due to the introduction of an invasive species, rats. The rats are a threat because they eat the tuatara eggs and hatchlings. The spread of rats started with the arrival of humans from Polynesia and then Europe. Once tuataras were common throughout New Zealand, but they are now confined to the northern islands.  The tuatara has had a long-term endangered status, starting in the late 1800’s.

These living fossils are struggling through the invasion of rats, which is rapidly weakening their status; however, it may be global climate change that is their demise.  Like many reptiles, whose eggs are like seeds in a garden, they are dependent on outside temperature for hatching.  One degree centigrade change of temperature can determine the sex from female to male. Since males are more likely at warmer temperatures, global climate change could mean there will be more males produced.

The Brother’s Island tuataras at the San Diego Zoo were a gift to the Zoo when they were young, with the hope that a successful breeding program could be started.  They are just now approaching breeding age, with no births at the Zoo yet. The survival of this living fossil may depend on the success of breeding programs such as those I learned about during week one of InternQuest.

Colton, Wildlife Conservancy Corner
Fall 2012, week one