The marine iguana (Amblyrhynchus cristatus) is a vertebrate belonging to the Squamata order, Lacertilia suborder and the Iguanidae family that has the peculiarity of being the only species of marine iguana in the world This peculiar lizard has attracted attention throughout scientific history, including Charles Darwin, because it presents interesting evolutionary adaptations that allow it to develop properly in the ecosystem it inhabits.
The marine iguana, in addition to being a unique species, is also a clear example of the impact that animals can suffer when human beings transform ecosystems, causing considerably negative effects on natural species. In this tab of our site we want to offer you more detailed information about the marine iguana, such as its characteristics, customs and habitat.
Origin of the marine iguana
This species is endemic to the insular region of Ecuador, inhabiting the Galapagos archipelago, which is why it is also known as Galapagos marine iguana. Evolutionary theories suggest that the origin of the marine iguana took place thanks to processes of transoceanic dispersal, which have been evidenced relatively recently. They occur when some animals (or plants) can travel from one land mass to another on "rafts" of vegetation, colonizing spaces where they were not previously found.
In this sense, the land iguanas present in America could have made this maritime journey and reached the Galapagos Islands, developing through of thousands of years the adaptations that we can evidence today. Currently, as a result of natural events (tsunamis, storms, among others), these types of processes have been recorded, but in these cases the animals travel on objects built by humans.
Because the marine iguana is present on several of the islands that make up the archipelago, seven subspecies have been identified, with the development of intraspecific taxonomies.
If you want to know more endemic animals of the Galapagos Islands, we encourage you to read this other article on Animals of the Galapagos Islands.
Characteristics of the marine iguana
In marine iguanas, males can measure up to 1.3 meters, while females only measureabout 60 centimeters Another of the main characteristics of marine iguanas is that they have keratin scales , and their skin is thick and hard, which helps them not to dehydrate easily. In addition, this gives them a waterproof body. For their part, they have flattened tails and have lateral undulations on the body, which makes it easier for them to swim. In addition, they have long and sharp claws that they use to climb the rocks of the coast and their particular anatomy of the snout facilitates feeding.
In order to excrete the excess s alt that they accumulate as a result of their diet, they have specialized nasal glands through which they expel this compound in the form of crystals. On the other hand, their coloration is dark gray to black, but they usually also have greenish and reddish colors. Given the dark coloration, they are easily camouflaged on rocks, but are easily visible on sand.
They are also excellent swimmers and can stay underwater for up to 45 minutes, for which they lower their metabolic rate considerably. However, when they are out of the water they are commonly kept in groups for thermoregulation purposes.
Habitat of the marine iguana
As we have mentioned, this species only lives in the archipelago that makes up the Galapagos Islands. The marine iguana enters the sea exclusively to feed The rest of the time it spends on the rocks or in the coastal area, but it can also be seen in the mangroves in the area.
This habitat is made up of a set of islands of volcanic origin, and are characterized by presenting two seasons with well-differentiated atmospheric conditions: one rainy and one warmer, which determines the type of vegetation on each of the islands. The biological plant formations are made up of mangroves, bushes adapted to the tropical climate and high salinity conditions, but due to certain specific humidity conditions, it is also possible to find ferns and particular herbs.
Customs of the marine iguana
Although they can be frightening by their appearance, they are calm animals and are not aggressive. Among the habits or customs of the species is swimming in the deep sea to feed. The rest of the time they use it to expose themselves to the sun, which they do in a group to raise their body temperature. This aspect is enhanced by its dark coloration, which facilitates the absorption of the sun's rays.
The marine iguana is one of the most striking vertebrates in the archipelago, and is not usually as elusive as its relative the land iguana (Conolophus subcristatus), which is also endemic to the Galapagos Islands. The efficient morphological development of Amblyrhynchus cristatus allows it to have access to the various spaces in which it is used to being within the habitat and, in addition, to its distinctive way of obtaining food.
Marine iguana feeding
They are herbivorous animals and feed exclusively on algae, for which they dive deep into the sea to obtain them, although they can also consume species that are present more superficially. These iguanas, thanks to the special shape of their snout and their small sharp teeth, easily manage to obtain algae from the seabed or from the rocks on which they grow.
Some scientists suppose that this species managed to reach this type of marine feeding because these islands are of volcanic origin, so the vegetation is very limitedor nonexistent in certain areas, so it must have developed adaptations to meet its nutritional requirements, in addition to acquiring the ability to excrete excess s alt from its diet.
Reproduction of the marine iguana
Females have breeding seasons in which males will actively seek to mate. In fact, they commonly breed with more than one female at a time. In this sense, monogamy is almost not present in the species and, therefore, the pairing time lasts a short time.
Marine iguanas are oviparous animals and the females dig in specific places to make their nests, in which they will deposit the eggs, which they may take up to 120 days to complete their development, however, they will only take care of the nests during the first weeks. Newborn iguanas are vulnerable to the few natural predators that the species has.
Conservation status of the marine iguana
The current status of the marine iguana is vulnerable, according to the red list of threatened species of the International Union for the Conservation of Nature. Its population is considered to be in a declining state and it is estimated that there are only about 200 thousand mature individuals throughout the archipelago. The main threats to the species are due to human impact due to transformation of the habitat for urban construction and pollution. Also the activities of tourism can cause some impact on the species. Previously, the marine iguana was not the victim of many predators, but due to the introduction of domestic animals, such as dogs and cats, populations of the species have been highly affected by this cause.
Although all animal species must be protected and valued, it is necessary that conservation actions be even greater in cases of endemic species, because being present in particular or reduced regions, their populations are much more vulnerable and susceptible, as is the case of the marine iguana, which is exposed to anthropogenic factors that must be urgently controlled to avoid greater impacts at its population level.
