Land Iguanas


 

SANTA CRUZ, Galapagos, Ecuador — They live in the driest, most sunburned parts of the Galapagos Islands and they look like miniature dragons. Some of them have mottled hides of burned orange and tan. Some are mainly yellow. And a few come in tones of pink. All of them are perfectly camouflaged for their home terrain.

The striking creatures are known as land iguanas.

They are much less well known than their cousin, the marine iguana, and at one point they were nearly extinct. But in the last few years they have been making a come back. According to scientists at the Charles Darwin Research Station on Santa Cruz Island, their ranks have grown to more than 13,500 and are slowly rising.

Jessica Cornejo, a Galapagos National Park guide, was born in the Galapagos and has been observing land iguanas for much of her life.  “They are amazing animals,” she said. “They can survive in very dry places without green vegetation and water.”

Like all the native wildlife and plants in the Galapagos, the land iguanas began life millions of years ago in other places. Scientists say they think the ancestors of the land and marine iguana somehow drifted on make-shift rafts of fallen trees and shrubs to the barren, mostly black volcanic islands from the mainland of South America, 600 miles to the east.

Photo by Thomas Rodriguez

Photo by Thomas Rodriguez

The scientists say they think the iguanas stem from a single species and that as they adjusted to their new home, some of them learned to swim and dive and hold their breaths for as much as 45 minutes, and to thrive on the algae that grows on underwater rocks close to shore.

 

That branch of the family became known as marine iguanas. They have evolved as totally black-skinned animals that are almost invisible on the black lava rocks where they sprawl in little colonies to warm in the sun after diving in the cold Galapagos water for their meals.  Scientists estimate that there are now more than 200,000 marine iguanas.

 

For whatever reasons, the land iguanas remained more like the first iguanas that arrived in the Galapagos. They never learned to swim and dive and hold their breath. Instead they hung out in the hottest, driest parts of the islands and they developed a love for prickly pear cacti, which also somehow found their way to the islands, perhaps as seeds excreted by birds or, like the iguanas themselves, as passengers on makeshift rafts.

 

Wild dogs ate many of the land iguanas and U.S. soldiers and airmen shot many others during World War II when they were posted in the islands as lookouts for enemy ships that could threaten the Panama Canal and as re-fuelers for allied air craft patrolling the Pacific and, in some cases, en route to the Pacific combat theaters.

 

American and Ecuadoran scientists intervened. They gathered land iguanas from several islands and began breeding them in laboratories. Ten years ago, the scientists decided that the land iguanas could make it on their own. And they closed the last of the breeding centers.

Photo by Thomas Rodriguez

Photo by Thomas Rodriguez

Now, though the land iguana communities are growing, some of the animals are having difficulty finding food. And they are getting another helping hand.

 

Teams of workers from the Galapagos National Park and the Charles Darwin Research Center have begun planting hundreds of prickly pear cacti, partly to restore the landscape after legions of the plants died in harsh weather and partly to provide food for the land iguanas.

 

Enrique Vargas, who has been a naturalist guide for the Galapagos National Park for 15 years, said he recently had been to South Plaza Island and had seen lots of land iguanas. “The population is coming back,” he said. “These animals are quite strong. They can survive without eating or drinking for seven or eight months. Their metabolism is quiet slow.”

 

With more land iguanas, Vargas said, comes more vegetation. The land iguanas eat plants and seeds. They excrete the seeds and the seeds grow into plants which provide food for more iguanas.

 

“When I see the land iguana population increasing,” Vargas said, “I feel good because it is good for the ecosystem. I know there will be more plants and more seeds. The finches and mockingbirds, all the land birds,  eat seeds. When you have more iguanas it’s good for the whole food chain.”

 

 

 

 

More like this: Galapagos 2016

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