The most popular are tortoises – you also find iguanas
The Galapagos Islands are a World Heritage Site. One of the things that set them apart is the uniqueness of the animals — especially the reptiles: ninety percent of the reptiles are endemic — found nowhere else on Earth.
In 1845, Charles Darwin wrote that the Galapagos Islands seemed like “paradise” for reptiles. He was right. The Galapagos are dry and hot at the most time of the year, and there’s not much to eat. Reptiles are adapted to these conditions. Their scaly skin is effective protection against the sun, and they can find shade if they’re hot. They have a slow metabolism, being “cold-blooded,” and therefore don’t need a lot of food. The Galapagos Islands also favor reptiles due to the lack of competition or predators in the form of native mammals. In the absence of mammals, Galapagos reptiles evolved to fill available niches. This is why most of the islands’ 22 reptile species are endemic. The land reptiles are divided into four main groups: tortoises, iguanas and lizards, geckos, and snakes. The marine reptiles are marine iguanas and sea turtles.
Herman Melville (the author of Moby Dick), another famous character who visited the Galapagos in 1837, right after Darwin, had his saying on the Islands fauna:
“Another feature in these isles is their emphatic uninhabitableness…Little but reptile life is here found: – tortoises, lizards, immense spiders, snakes, and the strangest anomaly of outlandish Nature, the aguano. No voice, no low, no howl is heard; the chief sound of life here is a hiss.”
While “immense spiders” certainly are not reptiles, the Galapagos Islands are indeed known for their rich reptilian population, beginning with the giant tortoises, the “Galapagos” from which the archipelago derives its name. It was the giant tortoises, with 11 subspecies scattered about the archipelago, that first called Darwin’s attention to the amazing diversity of the Galapagos wildlife. Sea turtles also call the Galapagos home. The most commonly seen sea turtle is the green sea turtle, which is considered to be endangered throughout its range, except in the Galapagos.
Lizards are represented by three major types – the iguanas, the Galapagos lizard, and the geckos. The iguanas fall into two basic genera represented by the marine iguana and the land iguana. There are two types of land iguana, usually considered different species, although there are some data to suggest that the two are actually different races of the same species. The lava lizards consist of a single genus, Tropidurus, divided into seven species scattered among most of the islands. Lastly, there are three endemic species of snake.
Galapagos giant tortoises
The namesake of the Islands
No animal is more synonymous with the Galapagos Islands than Galapagos Giant tortoise. Indeed, the saddle-back shape of the shell in many of the tortoise races reminded the early Spaniards of a type of riding saddle called “galapago”, and this term is also applied to the tortoises. Hence, by calling the islands the Galapagos, we are, in essence, calling them “The Islands of the Giant Tortoises”. The giant tortoise is the symbol of both the Charles Darwin Research Station and the Galapagos National Park Service. In the form of one particular individual, Lonesome George, the sole surviving member of the Pinta Island race, the giant tortoise is the symbol of the extreme fragility of the Galapagos islands and a reminder of the need for vigilance and conservation.
Voyagers travel offers several travel programs in the enchanted isles, every itinerary includes the possibility to encounter giant tortoises in their habitat. We organize custom Galapagos tours for individual travelers and groups.
It was also the giant tortoise that tipped Darwin off to the incredible diversity of the Galapagos fauna and flora. In the “Voyage of the Beagle,” he noted:
“I have not as yet noticed by far the most remarkableGalapagos Charles Darwin feature in the natural history of this archipelago; it is, that the different islands to a considerable extent are inhabited by a different set of beings. My attention was first called to this fact by the Vice-Governor, Mr. Lawson, declaring that the tortoises differed from the different islands and that he could with certainty tell from which island any one was brought. I did not for some time pay sufficient attention to this statement, and I had already mingled together the collections from two of the islands. I never dreamed that islands, about fifty or sixty miles apart, and most of them in sight of each other, formed of precisely the same rocks, placed under a quite similar climate, rising to a nearly equal height, would have been differently tenanted; but we shall soon see that this is the case. It is the fate of most voyagers, no sooner to discover what is most interesting in any locality than they are hurried from it; but I ought, perhaps, to be thankful that I obtained sufficient materials to establish this most remarkable fact in the distribution of organic beings.”
Charles Darwin, 1845
Of the 15 races of Galapagos tortoises, four are extinct. Because of breeding and release efforts on the part of the Charles Darwin Research Station, most of the remaining races are holding their own. However, there is still on-going poaching of tortoises by local residents. One race, that from Pinta is represented by a single surviving male, aptly named Lonesome George. The 15 races are:
- Galapagos giant tortoise (Geochelone elephantopus)
- elephantopus Floreana (extinct)
- not described Santa Fe (extinct)
- elephantopus phantastica Fernandina (extinct)
- elephantopus wallacei Rabida (extinct)
- elephantopus hoodensis Espanola
- elephantopus abingdoni Pinta (Lonesome George – extinct)
- elephantopus ephippium Pinzon
- elephantopus chatamensis San Cristobal
- elephantopus darwini Santiago
- elephantopus vicina Volcan Cerro Azul Isabela
- elephantopus guntheri Volcan Sierra Negra, Isabela
- elephantopus vandenburghi Volcan Alcedo, Isabela
- elephantopus microphyes Volcan Darwin, Isabela
- elephantopus becki Volcan Wolf, Isabela
- elephantopus porteri Santa Cruz
Found only in Galapagos Islands
Scientifically known as Amblyrhynchus cristatus, the marine iguana is the only seagoing or marine lizard of the world. Residing in the vast Galapagos Islands, this species has adapted well to the harsh environment of the sea. Although the species is similar in appearance to large lizards, it has developed blunt noses by feeding on seaweed, potent limbs with claws that aid it in clinging to rocks, and laterally flattened tails for swimming.
Here are a few facts about this incredible reptile:
The marine iguana is found almost throughout the archipelago, especially in the coastal areas with the population of around 4,500 per mile. The entire population is estimated to be 200,000–300,000.
This Reptile comes in many colors
The marine iguana is found in gray to black tones; it develops spots of red and coppery green color all over its scaled body during the mating season. This may happen because it consumes a specific kind of seaweed that grows in the summer season. It also has dorsal scales, an obelisk shape, running right from the head down to the tail.
Behind the Iguana Appearance
Although not attractive and considered scary at first, it is a tame and timid creature, and one of the most iconic symbols of Galapagos wildlife. Males are much larger in size than females, although both resemble each other in appearance. The juveniles also look the same; however, they are usually darker in tone.
Indeed, even Charles Darwin himself was much repulsed by it, calling it “a hideous-looking creature, of a dirty black color, stupid, and sluggish in its movements.” In his diary, he noted that :
“The black Lava rocks on the beach are frequented by large (2-3 ft) most disgusting clumsy Lizards. They are as black as the porous rocks over which they crawl & seek their prey from the Sea. Somebody calls them ‘imps of darkness’. They assuredly well become the land they inhabit.”
Charles Darwin, 1845
Feeding Habits and General Behavior of the Marine Iguana
This lizard mostly feeds on algae seen underwater and inside the tidal pools. It is also known for eating grasshoppers and crustaceans. When it goes hungry, it not only becomes thinner but also shorter. This finding is based on the report submitted by a scientist in the scientific journal, ‘Nature’. He concluded that this kind of lizard reduces in length in times of El Nino-induced famine and regrows to its actual size with the availability of food. This was later reported as the first case of shrinking of large adult vertebrae. The adult lizard can vary in its size during its lifetime. Many researchers have proposed that bone absorption results in shrinkage when the lizard eats and digests its bone parts.
Breeding of Galapagos Iguanas
- The male lizards guard their specific territories during the breeding season, and females place their eggs inside burrows.
- Marine iguanas are vegetarians, feeding primarily on seaweed in the intertidal zone.
High Mortality Rate of iguanas
The real cause for concern is the high mortality rate of these lizards as reported in a research conducted in 2002. This can be due to the long-term effects of the oil spill caused by the grounded tanker called Jessica in 2001.
They are found all around the enchanted isles
Land Iguanas (Conolphus pallidus or subscristatus) are vegetarian. These iguanas feed themselves most of the time with yellow flora and fruits of the islands such as prickly cactus pear and exist in two major forms, namely; Conolphus subcristatus which has yellow-orange coloration on Santa Cruz, Plaza, Isabela and Fernandina islands and secondly conolphus pallidus, which is decorated with brown and whitish coloration but is found only on Santa Fe.
Darwin was not much impressed with the land iguana:
“…they are ugly animals, of a yellowish orange beneath, and of a brownish-red color above: from their low facial angle they have a singularly stupid appearance.”
C. subcristatus once had a much broader distribution and higher population numbers than it does today. In 1835 Darwin was impressed with their numbers, remarking that:
“…when we were left at James [Santiago], we could not for some time find a spot free from their burrows on which to pitch our single tent.”
Today, there is not a single land iguana to be seen on Santiago. They have become extinct at the hands of man, or man’s introduced animals. C. subcristatus can be found on Santa Cruz, Isabela, Fernandina and, most dramatically, on Plaza.
The land iguana has a kinship in the American continent, with some structural and genetical differences. The most visible one is the color. While the Galapagos Land Iguana is yellowish brown to red, its continental relative is dark green to yellow.
Green sea turtles
There are several species of sea turtles in the Galapagos waters
Travelers to the islands of the Galapagos are far more likely to see a sea turtle in the wild than a tortoise, but in many ways, the experience can be more rewarding. Green sea turtles (Chelonia mydas) are found throughout the warm waters of the world, and between 1,200 to 3,000 females nest each year on six of the Galápagos islands. Typically they weigh between one and two hundred pounds, though some have been recorded up to 330 pounds; females tend to be larger than males. Their hard shell varies in color from black to green to yellow, regardless of sex.
Though the variety found in the islands is superficially browner than its continental cousins, there is evidence of interbreeding between the two varieties, so speciation has not occurred. Sea turtles are able swimmers, and the local variety has been found as far as 1500 miles from the Galápagos along the South American coast. They feed primarily on seaweed, and spend large periods of time underwater, “sleeping” on shallow sandy bottoms. They are usually seen by tourists from boats as they raise their heads above water to gulp air before disappearing for another long dive.
The nesting behavior of the sea turtle can be quite spectacular. There is no pair bonding — a female may mate with several, if not dozens of males, a process which can be exhausting. Female turtles are often seen hauled upon on the beach just above the surf line, taking a break from male attention. When she is ready to lay eggs, the female drags herself well above the high tide line, digs a large pit in the loose sand, and lays about 75 eggs at a time. These egg-laying excursions take place up to eight times during a breeding season, each session separated by a couple of weeks.
The high proportion of eggs for each individual — about 600 to 1 — is necessitated by the low survival rate of turtle eggs, due to climatic and tidal conditions as well as natural predators such as egg beetles, crabs, hawks, mockingbirds, and frigatebirds. In the Galápagos, sea turtles also have “unnatural” predators — feral pigs and rats are serious problems in some areas, though the relatively low density of human population has so far delayed direct threat.
Lava lizards and snakes can also be found in the Galapagos Islands
Three species of snakes (Philodryas biserialis, Alsophis slevini Galapagos snakesand A. dorsalis) occur in the Galapagos Islands, all endemic. They are quite similar looking, about two to three feet long, brown with yellowish longitudinal stripes.
The snakes have arrived on the islands via at least two colonization events. The Alsophis species appear related to A. elegans in Peru and southern Ecuador whereas Philodryas biserialis has a Chilean relative, P. chamissonis.
Galapagos snakes can be slightly poisonous to humans and may use venom to kill its prey. They first catch the prey with their mouths and mainly kill by constriction: wrapping around the victim and squeezing so it cannot breathe. They hunt for small reptiles and mammals. Prey includes lava lizards, grasshoppers, geckos and marine iguana hatchlings. They also feed on finch nestlings.
Although common and widespread, the snakes are not often seen as they are rather shy. Most islands have one or two of the species. A couple of northern islands have no snakes, presumably because they did not succeed in establishing viable populations or never reached there in the first place.
(Phyllodactylus) in the islands, rarely seen due to their nocturnal behavior and preference for dark places beneath rocks or fallen trees. They may be noticed at night in Puerto Ayora, however, climbing the walls of hotel rooms or squeaking rhythmically. Their diet consists entirely of insects, which their large eyes allow them to see, their quick speed to catch.
(Tropidurussp) is well distributed in the Galapagos island wildlife. In most species, you can tell the females from the red to orange necks. Their coloration varies from dull to bright red, often reflective of their immediate physical environment. There are seven endemic species, and some are even endemic from island to island. Found on all islands except the northernmost ones Genovesa, Darwin and Wolf.