The Marine Iguana
Adaptation at its finest

An Introduction
What makes the marine iguana so special? Why has it adapted in this way? Scientists say that at one time, these creatures were simple, unimportant iguanas.  So how and why have they adapted this way? What happened after their transportation to the Galapagos of the Ecuador mainland that gave the iguanas the ability to swim and stay underwater for up to half an hour? After intently studying this subject, I’m here to tell you all you want to know. About the Galapagos Islands, iguana endangerment, where this particular iguana came from and what makes it special.
 

 

 

The Galapagos islands

​

​

Darwin’s Exploration
In 1835, the young naturalist Charles Darwin was aboard the HMS Beagle.  Heading home after an exploration that no naturalist had ever experienced the like of, the ship was heading home after a 3 year trip that circled most of South America. Darwin had spent countless days of scientific research, ashore the pampas of Argentina or the Cordilleras of the Andes. Collecting specimens and studying the geology of the area. After the many phenomena his uniquely open mind began to question the strict rules of creation that ruled the minds of most scientists of the day. The idea that everything stayed the same over time seemed to close minded after his close observations of life at work.  The most influential to most of his new ideas was his work on the Galapagos. There he had observed that hardly any species stayed the same after being isolated from the mainland, adaption was necessary to survive.  After returning to England, Darwin was able to come up with the idea of natural selection, an idea that is now one of the main ideas of environmental science. There is a good chance that without his adventures on the Galapagos, Darwin’s theory would be majorly deterred. In return, he is given much credit for the science of the Galapagos, and there is an immediate connection between them. 

​

The Creatures of the Galapagos

The observations that Darwin made are not credited to just one animal, though one of the most famous are Darwin’s finches. Many animals are endemic to the Galapagos as Darwin’s theories have affected almost all of its inhabitants. Some of the well-known include the Giant Tortoise, who are known not only for their mass but also their long lasting lifetime as well as the Marine Iguana, of which this report is about. There are also 2 species of  more regular land iguanas, who don’t seem to have evolved as much to the unique abilities of the marine iguana, but are also endemic to the Galapagos and within that only some of the islands.  There are also countless more species that you would not find anywhere else in the world, no matter where you traveled.

​

Geography and location
−  The Galapagos are located 696 miles off the coast of Ecuador, at 0° S 91° W. Their location creates warm temperate conditions brought on by vigorous upwelling (Equatorial Undercurrent) and a moderately cool, warm temperate-subtropical influence (Peru Flow). Ocean temperatures can vary from 0 to 27 degrees centigrade, (in the majority of areas inhabited by the marine iguana colonies, water is frigid.) . The Galapagos are quite volcanically active, with almost all the islands in the region centered around large, cone volcanoes. A more arid zone is found immediately inland from the coastal zone, and is the most widespread formation in the islands. The humid zone emerges above the arid zone through a transition belt in which elements of the two are combined. It is a very damp zone maintained in the dry season by thick, garua fogs which accumulate through most of the night and last well into each day. A fern-grass-sedge zone covers the summit areas of the larger islands where moisture is retained in temporary pools. The ending result is a varying environment that can differ on all islands, as Darwin observed in his trip there.  These varied conditions also create difference in the marine iguana family, as colour  and shape vary from island to island.
​

​

​

​

The Endangerment of The Iguana

​

​

The Species at Stake

There are many different species of iguanas, and almost all of them are endangered in some way. Whether it be hunting, disease, habitat destruction or being road kill, or many more creative examples. On the IUCN Red List, 23 species of iguana are from near threatened to critically endangered. Including 1 extinct species, the Navassa  Rhinoceros  Iguana. The marine iguana among them. Some of the most critically endangered are the Fiji Crested Iguana, Galapagos Pink Land Iguana, Utila Spiny-tailed Iguana and most South Indian Rock Iguana species.

​

The Cause

As said before, the cause of endangerment varies in each place. In the Lesser Antilles (home of the West Indian Rock \ Lesser Antillean  iguana) the destruction of the environment by agriculture, timber industry and growing population have caused the iguanas from being the most populous animals in the region to being critically endangered.  In the Blue Iguanas environment of The Grand Cayman Island, global warming has caused large decreases in population. And the list goes on…   In some places hunting and being turned in to road kill causes some species to become threatened where as in other there simply weren’t that many in the first place.

​

Help?

Large problems don’t always need a large help force, but that doesn’t mean that people aren’t prepared to give one.  At first it seems kind of confusing, all you see are a few small programs or organizations every once and a while who say “We’ve helped over  blah blah blah iguanas already!” and it doesn’t seem like that much.  However, than you look a little deeper and see not the number in the sites but the number of site. They may be little , but there are thousands of them.  So in a way a movement is starting with just a few.  If you simply take the small numbers of each small site  and you add them all together you get numbers larger than any few big programs could produce. In addition to that there are also the big programs that are donating some of their work the cause. In the end you get a large movement out of many small ones.

​

​

​

​

A Day in The Life of Amblyrhynchus Cristatus

The unique ability of the marine iguana is its ability to go under water, that is what makes it the marine iguana. Almost its entire day is focused around this ability as it is the key to its survival. If one were to go through the day with almost all the details. It would often be said repeatedly that a certain habit was because of their main habit to go underwater. However, because of this and its name (marine iguana) one would presume that this creature spends a majority of its time underwater or perhaps even live underwater, this person would be misguided. An iguana of this species would spend at the most 20 minutes of the day underwater. Usually only 10 minutes!

​

Long Lazy day
The day of a marine iguana is quite long, starting at dawn and ending at dusk. However, it is made up for by the fact that most of the day is spent in lazy relaxation, to make up for only ten minutes of rough, energy straining feeding. Waking up at dawn the iguanas hardly move, often residing in large colonies simply basking in the sun on the rocks. They usually can be found continuing until noon, when the stronger iguanas take a plunge into the frigid waters to feed. Using their strong alligator like tail, they can propel themselves down to the rocks below, where marine algae thrive. This procedure can take only 10 minutes, including the hasty retreat back to the rocky shore.  After this thrilling experience, the colonies spend the rest of their day sun basking once more. Falling to sleep once more at dusk

Feeding Affects

Though the feeding process may only take 10 minutes, it affects almost every other point of the day. Since iguanas are cold-blooded animals, finding warmth is a never ending struggle. The effects of this are multiplied by the fact that some of their day is spent in very cold temperatures (the water) which are often cold enough that their muscles would freeze should they stay to long. Therefore, basking in the sun becomes a necessary precaution to insure that body temperature stays at a reasonable level. In this way there short struggles almost cause their long periods of laziness. This makes the small ten minutes that hardly seem to mean anything become the most important event of their day, with all other activities centering around it.

​

​

​

​

Adaptations, Whats So Special?

​

​

Adaptations that stand out
The most obvious adaptation of the marine iguana is its ability to go underwater; however, this ability is made up of many smaller but more specific adaptations to its body. Perhaps the most important is the tail, the iguana’s tail 1 and a half the size of its body. Largely flexible but very strong and muscled, it heavily compares to that of an alligator. Being laterally flattened to move more water, the tails can easily propel the iguana forward as well as help it turn while turning, it also provide balance when gripping onto the slippery rocks against the strong ocean currents that surround the Galapagos. Though the tail seems the most influential, other abilities are needed to complete the ability to not only dive underwater but feed underwater. Such as the claws, which are very strong and thick, note forgetting sharp. These can dig through algae and grip strongly to the rock that the iguana happens to be feeding on, allowing it to stay stable and feed thoroughly on one rock before moving on. Two more adaptations are essential, the mouth and snout and the salt glands. The marine iguana species has razor sharp teeth, perfect for scraping the algae off of rocks. The face or snout is also more blunt than with other iguanas so that the mouth can fully reach the rock, as well as the skin in that area being very thick so as not to be scraped by rough rocks.  The salt glands mentioned are small glands placed directly under the creatures eyes. These clean the iguanas blood of extra salt that is consumed from their diet and salt water swallowed when underwater. The salt can be easily sneezed out of the glands, though the salt often simply lands back on the iguana, creating a distinctive cap of salt on their heads. Though this adaption is not directly used underwater, it completes the underwater process.

​

In Comparison
In comparison to other iguanas from different environments, this particular iguana shares some similar features with different species but for the most part is different. For instance, the tail is the same ratio of tail to body as on other iguanas, but at a close up; the tail is laterally flattened where as with most other iguanas it is more round. There are also some interesting facts\abilities that the iguana shares with other iguanas.( Such as the ability to lose half of their tail if needed.) Then there are the basics, such as what is needed to be counted as a iguana or even a lizard, like being cold blooded. Other than these, the marine iguanas or Amblyrhynchus Cristatus, have very little in common with other iguanas. 

A Conclusion
The marine iguana is an animal of never ending interest, there is an eternity of research to be done on them and still perhaps not everything will be known. This report has been a most short amount of knowledge out of a endless well of it. Perhaps it is the idea that these iguanas were once just a humble creature with nothing different than any other in Ecuador before they somehow got to the Galapagos and became what they are today, a creature to forever be admired.