A marine iguana’s funky, fine mist

Photos: Iguana portraits by Sam Noddle; Iguanas with people by Joseph B. TreasterThe magnificent marine iguana, one of a handful of creatures found only in the Galapagos

Strong Swimmers,
Prehistoric looking

A marine Iguana, about as long as a baseball bat and just a little wider,  stretched out on the hot concrete in the afternoon sun at the edge of a boat ramp on Santa Cruz Island in the Galapagos Islands. It opened its eyes and exhaled a funky fine mist.

“Marine iguanas have adapted a special gland connected to their nostrils to help them get rid of excess salt from the ocean,” said Jorge Cordero, a Galapagos Natural Park guide who was watching the iguana that afternoon.

The iguana stayed completely still as five chatty tourists stepped up to within three feet of it, the closest allowed in the Galapagos National Park. The tourists moved on. The iguana opened its eyes and shot out another blast of mist.

The marine iguana is an example of Charles Darwin’s theory of evolution. It has adapted to the dry, coastal climate of the Galapagos Islands in the Pacific Ocean, 600 miles off the coast of Ecuador.

The marine iguana has become one of the symbols of the Galapagos Islands. Their pictures are on tee shirts and travel brochures. One of the dive shops on Santa Cruz Island even calls itself “Scuba Iguana.”

Tourists come to the Galapagos from around the world. John Reid, who owns a company that makes protective packaging for coils of raw steel in Auckland, New Zealand, was spending a week with his wife aboard a small boat, stopping at several islands. He had seen lots of marine iguanas on the trip. “Cool,” he said. “Very good.” To him, they looked, “prehistoric,” like something from “years gone by.”

Researchers say that iguanas first arrived in the Galapagos from mainland South America more than 10 millions of years ago, floating on rafts of tree branches and other debris. At first, they couldn’t swim. Some of them went inland to make homes in the scrub brush and behaved much as they had before migrating. Others stayed on the coast and eventually began going into the sea to eat algae. They became good swimmers and divers. Those iguanas are called marine iguanas. The males can stay underwater for up to an hour. Marine iguanas are found only in the Galapagos Islands.

Scientists say no one has done a formal census of marine iguanas, but estimate that their population ranges from 300,000 to 400,000. They live in colonies along the rocky, volcanic shorelines of the islands.

There are seven different subspecies of marine iguanas. The largest lives on Isabella Island, the biggest island in the Galapagos archipelago. Male marine iguanas grow up to five and half feet in length. Females are smaller. They are often two to three feet long.

Marine Iguanas live up to 60 years. They nest several hundred yards from water in the soft sand. Females lay between two and three large eggs that hatch in about three months. The newborn are vulnerable to rats, dogs and Galapagos hawks.


Sam Noddle

Marine iguanas have strong claws and flat heads with razor sharp teeth that they use to peel algae off volcanic rocks. They whip their powerful tails from side to side to propel themselves through the water.

Like all reptiles, marine iguanas have no built in body temperature regulation. When they are cold, they sit in the sun. When they are warm and hungry, they dive into the ocean.

Cordero, the National Park guide, said that like human free divers, marine iguanas preparing to dive, slow their heart rate to about 10 beats per minute, down from their usual rate of around 40 beats. That helps them stay under water longer, he said.

Weather can have a profound impact on marine iguanas. A phenomenon known as El Nino occurs every seven to fifteen years. One of its effects is a warming of the Pacific Ocean. Great swaths of algae die. In one El Nino 30 years ago, scientists say two out of every three iguanas died.

Late one morning at Tortuga Bay on Santa Cruz Island, a big marine iguana climbed out of the dark blue water onto a pile of volcanic rocks. Waves broke on the rocks and sent a frothy spray flying over the iguana. He seemed to have a kind of swagger. Roslyn Cameron, a development officer for the Galapagos Conservancy, has been watching marine iguanas for years. “They look at you like, ‘yeah, and so what?’” she said. “They have adapted, just like humans have.” #

 

One response to “A marine iguana’s funky, fine mist”

  1. Gabriella says:

    Super informative article. Must say I loved the ending.