The Galapagos Islands are well-known for their evolutionary theory, yet this theory alone can not explain their uniqueness—evolution occurs everywhere, at all times, and in all forms. Instead, it’s the extreme forms and clarity with which this process transpires; it’s so effective that noticeable alterations can be seen within a single population within a short period. However, it still surprises us in this “living laboratory of evolution.” The Hybrid Iguana in Galapagos, which has been living in the Galapagos Islands for decades, is a new species of iguana that has only recently been found. It was the product of unusual conditions.
The marine and terrestrial iguanas are the two species of iguana found in the Galapagos Islands, separated by a potential 10.5 million years of evolution. However, it has just been established that these two distinctly different species are hybridizing on the tiny island of Plaza Sur, which is about a tenth of a square mile in size, producing a very rare and uncommon lizard.
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Hybrid Iguana in Galapagos: An Uncommon Tale
While participating in a US Peace Corps land iguana conservation effort, biology professor Howard Snell discovered the first “strange” iguana in 1977. He described the iguana as “very intermediate in a lot of characteristics between land and marine iguanas,” perplexed by its odd traits and unable to classify it as a marine or land iguana.
He soon realized that this “strange” iguana was not bizarre and might be the extraordinary consequence of interbreeding between marine and land iguanas after observing several of these mixed iguanas throughout his studies. But he only knew for sure what he had seen 20 years later when the hybrid’s existence was established. He observed only 17 of these animals throughout the 23 years he worked on this study.
Snell is one of the few people who have ever seen these animals; in fact, just 20 have ever been sighted, and many guides working in the Galapagos Islands for years have never seen one. Only four hybrid iguanas were discovered by Charles Darwin Foundation researcher Alizon Llerena during her 2013 census of the iguana population on Plaza Sur. These hybrids are uncommon because they are sterile, meaning they cannot procreate and pass on their peculiar features.
Galapagos Iguanas
Being the only seafaring lizard in the world, the marine iguana is a beautiful example of natural selection and evolution. Its primary food source is algae that grows on rocks on the ocean floor. Thanks to their flat faces, they can better grasp the algae with their teeth and hold onto the rocks even when strong waves try to knock them over, thanks to their long, sharp claws. However, as their name implies, land iguanas are only found on land, and their primary food source is prickly pear cactus. Unlike the sea iguana, the land iguana has a pointed face that shields its eyes from the spines of the cactus while it grasps the plant.
The hybrid marine-land iguana is essentially a cross between the two species, and its distinct behavior is adapted to fit its physical attributes. If one is fortunate enough to spot a hybrid, it can be identified by its distinctive black coloring and long yellow stripes that adorn its neck and chest. Galapagos hybrid iguana in Galapagos are terrestrial animals, yet they exhibit traits common to marine iguanas, such as their flat, rudder-like tail and large claws.
As a result, they are thought to be able to live in both aquatic and terrestrial habitats. It’s interesting to note that this terrestrial animal has an advantage over land iguanas due to its marine characteristics. For instance, it has even been seen that the hybrid iguana in the Galapagos consumes seaweed. What’s even more intriguing is that, unlike its land-dwelling relative, it has been observed utilizing its powerful claws to climb trees and cacti. It was previously unknown that Galapagos iguanas exhibited this behavior.
So What?
The breeding seasons of land and marine iguanas in Galapagos are known to be distinct, yet on Plaza Sur, these seasons hardly overlap. As a result, marine iguanas that arrive late in the day may be forced to mate with those that have just started to arrive. The tiny island, where the two species must coexist, provides more evidence. Interestingly, only male marine iguanas and female land iguanas can hybridize.
Generally speaking, hybridization is terrible since it decreases a species’ gene pool and biodiversity, which raises the possibility of extinction. However, the finding of the hybrid iguana in the Galapagos has left experts unsure of what to do. The hybrid iguana in the Galapagos is a new and highly uncommon species that arose via an entirely natural process uninitiated by human interference. The dilemma is whether to eliminate the possible threat, save the endangered species, or let nature alone. While doubtful, the hybrid may impact the evolution of Galapagos iguanas.
