The Plight of the Iguana
When he visited the Galapagos Islands in 1835, Charles Darwin came across all manner of lizards inhabiting both land and sea, but as he was unable to reach the top of the mile-high Volcan Wolf, he returned home without ever setting eyes on the pink iguana now known as Conolophus marthae. In fact it would be another century and a half before scientists would stumble on the unusual-looking creature, which lives only on the volcano. They dubbed their 1986 discovery "rosada," for its alluringly tinted skin, and then promptly forgot about it.
Another quarter century passed before anyone paid the lizard any real attention. And it’s no wonder: Biologist Gabriele Gentile of Rome’s Tor Vergata University and colleagues had to make two separate trips involving helicopters and days-long hikes (hacking a pathway up the slope with two weeks’ food, drink, lodging, and field equipment strapped to their backs) before they were able to tag, observe, and DNA-sample enough lizards to accumulate the information necessary to actually announce a classification.
"I gave it the name of my second daughter," Martha, Gentile says of C. marthae. "That should give you an idea of how much I care about this species."
Turns out it desperately needs caring about. There may be fewer than 200 pink iguanas left in the world, says Gentile. Though its only native predator is a Galapagos hawk, invasive feral cats and black rats (which first arrived on the Galapagos aboard ships in the late 17th century) have been attacking the lizards and decimating their habitat. Meanwhile, says Gentile, the iguanas hold important clues to the evolutionary history of the islands. DNA testing of C. marthae has revealed that the species split from the two other species of Galapagos land iguanas between 5 and 6 million years ago -- around the same time humans were diverging from chimps. Their earliest ancestors are older than Volcan Wolf itself, and may have preceded any of the Galapagos Islands currently in existence. Since the land where they originated has disappeared, scientists may never know where C. marthae came from or how the members of its lineage changed over time. What they have found is that in addition to the lizards’ striking coloration -- black stripes decorate the dramatic rose-colored flesh -- the iguanas evolved a pattern of bobbing their heads that is different from the behavior of other iguanas. This unique "language," used to initiate courtship and to threaten other males, may act as a communication barrier that keeps C. marthae from mating with other iguana species.
There is still much to learn about C. marthae, says Gentile, including details about its diet and how the few individuals that remain are genetically related -- information scientists will need if they decide to breed the lizards in captivity in a last-ditch effort to rescue them from extinction. He and his team are trying to confirm exactly how many of the iguanas remain and how their population may have changed over time, in part to help the lizards qualify for a "critically endangered" status from the International Union for Conservation of Nature. Raising awareness about C. marthae’s history and present plight could do more than just preserve the iguana, says Gentile. "Saving the pink iguana means protecting the whole environment where the species lives."