nature.net
July-August 2006
Reptilophilia
By Robert Anderson
I’ve never been much for pets—too much responsibility. Once, though, when a herpetologist friend offered me a turtle that had been turned over to him by customs agents, I said yes. A victim of the illegal pet trade, it was a big-headed turtle (Platysternon megacephalum, similar in appearance to New World snappers) that had flown in from the wilds of Southeast Asia to New York City before it was confiscated. My turtle was an admirable beast with a powerful, hooked beak to crack open crustaceans and mollusks. He was also adept at stalking small fish. “Jaws”—I guess the name was inevitable—taught me that, in the end, turtles can be lightning fast. You can see photographs of his species at the Platysternon Gallery.
Jaws gave me an appreciation for turtles, and for reptiles in general, a group with more than 8,000 known living species. Go to the TIGR Reptile Database and click on “How many species?” for a breakdown of the clan and a link to a map showing its global distribution. Nearly a quarter of all reptile species are harmless colubrid serpents, which include garter snakes. The second greatest number of species are the skinks, followed by the geckos. The only two surviving species of an entire reptilian order, the tuataras, live on islands off the coast of New Zealand. Both are endangered, and climate change may finish them off (see “New Zealand reptile in climate peril”). The Center for North American Herpetology has links to comments on the taxonomy and photos of local species.
Although reptiles are popular as pets and in zoos, real enthusiasts enjoy spotting them in the wild. At the Web site of Mike Pingleton, an amateur herpetologist, click on “Notes from the Field” to read about his adventures tracking down hundreds of species of frogs, lizards, snakes, and turtles. Another intriguing site, Flying Snake, may not be for everyone, particularly if serpents give you the willies. Movie clips document how certain Southeast Asian tree snakes propel themselves through the air, gliding from branch to branch [see “Serpents in the Air,” by Adam Summers, Natural History, May 2003].
You can learn a lot about human biology from the differences and similarities between reptiles and mammals. What are the advantages of being hot- or cold-blooded? Go to NASA’s Warm and Cold-Blooded Animals for an illustrated discussion of the various approaches to regulating body temperature.
Thermal regulation and other differences aside, human beings share much with reptiles. Unlike amphibians, which must remain in water to reproduce, reptiles were the first animals to have eggs with an amniotic sac, which enabled them to fully conquer land. At the Tree of Life Web Project, you can read more about how reptiles paved the way for later vertebrates. Dinosaurs, birds, and mammals, all with an amniotic sac, are all descendants of early reptiles.
Another bit of anatomy people inherited from reptiles is the core of the brain. A detail diagram can be seen at Brain Channels.com. Some mental-health problems are rooted in our reptilian brains, so you may want to blame your obsessive-compulsive disorder... on your turtle.
Robert Anderson is a freelance science writer living in Los Angeles.
Copyright © Natural History Magazine, Inc., 2006