The Galápagos land iguana lives on several of the islands and the biggest adults can weigh up to 30 lbs. Nesting periods vary from island to islands, and females bury anywhere from two to twenty eggs in burrows. Rare hybrids of land and marine are known to exist on little South Plaza Island, and both species can be seen there side by side. Land iguanas feed mainly on plants but also feed on whatever else is available, even carrion.
To remove the small and annoying spines of cactus fruit, land iguanas are known to roll them repeatedly over sand and stones before eating them. These reptiles have a life expectancy of about 50 to 60 years. Invasive mammals have taken a strong toll on these iguanas, with rats attacking eggs, and feral dogs the adults, but the national park’s programs to eradicate introduced species have helped the iguanas recover. Their current population is estimated between 5,000 and 10,000 animals.
During the hot season (December-May) their courtship behavior is quite amazing to observe, full of aggressive chasing, territorial displays, and the development of bright brown and yellow coloration in their skin.
The marine iguana is one of the most amazing Galápagos species. Darwin referred to them as “imps of darkness.” They arrived as terrestrial iguanas, and then evolved into their marine status and then spread throughout the archipelago, a great example of Darwin’s idea of natural selection. They are found on all Galápagos Islands – but nowhere else.
Their critical adaptations to a marine habitat include a reduced heartbeat and constriction of blood vessels near its skin to avoid temperature and oxygen loss. A shortened snout with small tricuspid teeth allow them to graze on the narrow algae they forage at low tide.
Their life span is shorter than land iguanas, only around 40 years. Visitors to the Genovesa island will find the smallest and blackest marine iguanas. While on Fernandina and Northern Isabela can be found the largest marine iguanas. Floreana and Española harbor the most colorful subspecies.
Santa Fe Land Iguana
Santa Fe Iguana
The Santa Fe land iguana, defined by its smaller dorsal spines, more brownish color, and tapered snout, lives only on the little island of Santa Fe. Perfectly adapted to blend in with its surroundings, it is somewhat more difficult to observe than the other land iguana.
The Santa Fe land iguana is categorized as vulnerable given its tiny geographical distribution. The eradication of feral goats in 1971 has helped the species to survive. The 3-11 eggs females lay take about 50 days to hatch in their burrows. This island-endemic reptile can only be seen on Santa Fe Island.
Galápagos penguins are the only penguins that live on the equator, the only penguins that molt twice a year, making them the rarest of all 18 species of penguins. The Galápagos penguin is also the only species of penguin that has no set breeding season, can lay eggs up to three times in a year, and, when food is abundant, can raise two chicks in about three months. They mark an astonishing deviation from the rest of the penguin family.
These penguins can survive on the equator because their breeding biology is adapted to the unpredictable upwelling of productive, nutrient-rich water in the Galápagos archipelago. During breeding, they shed their feathers around their eyes and bill so they can lose heat, and they stand with their feet in the shade to avoid the hot black lava.
Unfortunately, the current population is less than half of what it was in the early 1970s, with somewhere between 1,500 and 4,700 individuals. The population of Galápagos penguins has not recovered because of several severe El Niño’s in the 1980s and 1990s and the introduction by whalers of predators like rats and cats to the islands.
Galápagos Sea Lion
Similar to the Galápagos Penguin, the Galápagos sea lion is another unique seal species as it lives right on the equator and is exposed to greater heat and less food than colder-climate species. The productivity of the water around the Galápagos, as well as the sea lion’s adaptations, allow it to thrive nonetheless. This is the smallest species of sea lion, with females only weighing around 165 pounds and males up to about 440 pounds.
They live throughout the Galápagos, but most densely populate the central islands. Given that they are an endemic species in a small area, they are still listed as endangered. Excellent divers, they can descend up to 1,900 feet in search of food. Visitors may see sea lion pups during most of the year but most births are October and November. During this time, dominant males defend their territories and harems along the shore, living off their fat reserves, while smaller males may try to sneak in and find a mate. This can make for quite an entertaining afternoon spectacle.
Galápagos Fur Seal
Galápagos Fur Seal
The Galápagos fur seal is the smallest of all seals. It appears to have arrived in the archipelago relatively recently and is more similar to its mainland relative than the Galápagos sea lion. It currently numbers around 15,000 individuals but can be highly susceptible to El Niño events which break down the food chain these seals rely on.
They live mostly on Fernandina and the western side of Isabela, but can often be seen in other parts of the Galápagos, notably Puerto Egas, North Seymour, and Genovesa. Solitary males can occasionally be found all over the archipelago. During breeding season, between September and December, males however defend their territories for two weeks to a month at a time, living off their fat reserves.
Galápagos fur seals tend to hunt well offshore at depths between 200 and 330 feet, seeking fish and squid that at night tend to rise to these depths from further down. The bright light of the moon keep this ascent from happening, so that most fur seals tend to spend nights around the full moon on land.
Galápagos Giant Tortoise
Galápagos Giant Tortoise
The Galápagos giant tortoise is one of the most iconic Galápagos species and the largest living tortoise species. They can weigh up to 550 pounds and numbered around 200,000 before humans discovered the islands and now number around 20,000. The islands’ dominant plant eater, they play an important role as their habitats’ top grazer. The shape of their shells varies from island to island and, on Isabela, even from volcano to volcano. Islands with humid climate have larger tortoises with domed shells and shorter necks whereas dry climates lead to somewhat smaller tortoises with “saddleback” shells and long necks. Growing slowly, they often live to become well over 100 years.
Young tortoises are kept until they have grown large enough to be safely released into the wild to boost their survival rates against attacking rats and cats. Inside the Galápagos National Park, visitors can see them at Urbina Bay on the Western Islands itineraries; they can also be seen in their natural habitat in the highlands of Santa Cruz and at breeding centers in Puerto Ayora and at Cerro Colorado on San Cristóbal.
Also called the waved albatross, the Galápagos albatross is the largest bird in the Galápagos, with a wingspan of up to 8.2 feet. They breed exclusively on Española Island, except for a handful of albatross on the continental Ecuadorean island of La Plata. Close to 35,000 breeding pairs exist, but they have been considered critically endangered since 2007 due to the vulnerability of having a single main breeding site. Albatross have a spectacular mating dance of circling and audible clacking of beaks.
Unlike most other animal species of the Galápagos, the waved albatross has a predictable breeding cycle, and for a very good reason: all couples and hatchlings must leave Española before the winds fade away in mid-January. Being so large and heavy, any albatross staying on after that yearly change in weather patterns literally becomes stranded until winds pick up again around April; hence, eggs are laid between April and June and incubated for two months to get out in plenty of time.
Best known for their colorful anatomical features, the three species of boobies that nest on the Galápagos belong to the Sulidae family of seabirds. Sometimes looking comical on land, they catch fish with spectacular plunge dives, often chasing fish while underwater. The Galápagos boobies are endemic as sub-species.
Their conspicuous, unreal-looking blue feet, as well as their famous, amusing mating dance, during which the male shows off its feet in up-and-down movements to attract females are a wildlife highlight for many visitors. The most attractive feet for potential mates are those of a more turquoise blue, rather than the deep blue, indicative of how good a male is at feeding himself. While they also nest in other parts of Latin America between the Pacific Coast of Mexico and Peru, around half of all blue-footed boobies live on the Galápagos.
At the same time, while these are generally the most commonly encountered boobies, they happen to be the ones with the smallest population. The most important breeding colonies exist on Española Island and North Seymour. But the dramatic sight of plunge-diving boobies may be witnessed on any given day throughout the archipelago’s waters. Reliant on diving into the sea to feed, their nostrils are fused, hence it breathes through the corners of its mouth. Unusually for boobies, they may raise more than one chick at a time, although during times of scarce food competition is harsh and first-hatched chicks may kill their smaller sibling. The blue-footed booby is considered non-threatened.
This largest booby present on the Galápagos, covered in snow-white plumage and with black feet, is the most violently competitive Darwinist among them all. They are bad neighbors, both to their own species, and to their cousins, the blue-footed boobies.
These birds mainly nest along the shoreline, up to 300 feet inland on Genovesa. Hatchlings regularly commit fratricide, mostly by pushing the smaller brother or sister out of the nest, without the parents taking any action. Female Nazca boobies do lay two eggs four to five days apart so that, if the first is broken or eaten, the second may yet produce an offspring. When flying, they can be identified by the black wing and tail feathers. Despite the toughness of its competitive life, it is also listed as non-threatened, with a population estimated at around 30,000, but its global number is estimated to be declining. They can be seen on Genovesa, Española, and Floreana.
Ironically, the least seen booby happens to be the most numerous on the archipelago: the red-footed booby. They nest mainly on Genovesa Island, as well as San Cristóbal, but may occasionally be seen elsewhere in the archipelago. For them, to live in the corners of the archipelago makes perfect sense, as these boobies forage on the outskirts of Galápagos waters. They have a particular taste for flying fish, which they catch thanks to their ability to fly at high speeds. Its beak is light blue, turning to pink around the mouth and above the eyes, and its feet are characteristically red, with white claws.
Adults have feathers varying from white to brown tones. At the same time, hatchlings look much like the Nazca boobies, all in white with black beaks. They generally build their simple nests in low-lying branches of trees or bushes, unlike all other booby species. To do this, they have longer toes than other boobies, allowing them to grasp and hold on to twigs and branches. They lay only one egg. If it is lost, females may lay another within 10 to 40 days.
The Galápagos or flightless cormorant is the rarest, biggest, and most unique cormorant. This bird probably evolved in the center of the Galápagos before migrating west in tune with a major shift of high marine food productivity upon which it had come to rely.
Uniquely among cormorants and marine birds overall, it lost its ability to fly, eased by the absence of terrestrial predators, but mainly to adapt to its need to grow a larger body to dive. Mostly it dives at depths of around 33-45 feet, but can go as deep as 260 feet if necessary. Adaptations to its feeding habits also include its feathers, which resemble fur and aren’t covered in oil, and its solid bones.
The most unusual trait of these birds may be their mating system: sex roles are partially reversed in courtship – i.e., females lead and are more active than males in courtship and compete aggressively for access to males. The female normally deserts its mate and offspring to re-mate serially with different males while males raise the young unaided. Due to their restricted range, they can only be encountered on voyages through the Western Islands.
The flamingos present in the Galápagos belong to the American flamingo but are an odd southwest outlier, considering that the remainder of the species breeds along coasts of Colombia and in much of the Caribbean. Young flamingos lack the pink coat and feed on their parent’s “crop milk” secreted by another specialized gland in both male and female parents.
Flamingos have the largest and heaviest tongues among birds as the feeding techniques of baleen whales and flamingos are very similar: both can filter large amounts of very small food in very large quantities with the help of specialized filters.
Courtship rituals among flamingos form one of nature’s most impressive shows. Adult males and females aggregate in close groups and start an intricate dance with necks cocked up while flashing their primaries (the long flying feathers at the wing tips). These are exceptionally pink and black as they are less exposed to abrasion, wear and tear and other factors that may weaken the color intensity.
The most recent bird-count registered 314 individuals of this species in the archipelago. Visitors can see American flamingos on all the central and western Islands.
Magnificent Frigate Bird
Magnificent Frigate Bird
Unusually, two different species of frigate bird coexist practically side by side on the Galápagos: the great and the magnificent, the two largest species of frigate bird. The magnificent is more pelagic, foraging for fish out at sea for long periods of time, while the great is more coastal. They catch most of their food on the wing, sometimes robbing other seabirds.
In their larger colonies, both species nest near each other. Males’ impressive red gullar sacks – which inflate to bright red heart-shaped balloons – are among the most eye-catching feature of Galápagos breeding colonies. It takes around a half hour for the sacks to fully inflate.
Male great frigates have a green sheen on their shoulder plumage, while magnificent males have a purple sheen. The easiest to tell apart are juveniles and females: Magnificent frigate females have a black triangle of feathers running down from the base of the chin to the center of their white chests.
As a result, a white “M” is visible from below. Great frigate females have white all the way up their chins. Juvenile magnificent frigates have a white head, while great frigate juveniles have a rusty tone. All Galápagos locations will have frigatebirds flying around, and top places to see their nesting colonies include San Cristóbal, Española, and Genovesa Islands.
In the archipelago, the distinction of being the top predator belongs to the Galápagos hawk. As the apex predator, it has no natural enemies. Genetic investigation indicates that it is among the most recent native arrivals to the islands, having reached them around 300,000 years ago, compared with the famous finches, who arrived two to three million years ago.
They are present on most islands, but uncommon, with perhaps 150 breeding pairs. The fact that they are not found on Genovesa Island seems to be linked to the fact that Genovesa has no lava lizards, the key food species of Galápagos hawks. They also prey on young land and marine iguanas, hatchlings of tortoises and sea turtles, as well as insects like locusts and centipedes. They may hunt in groups of up to three hawks and sometimes feed on carrion.