Few places have influenced our understanding of nature and wildlife as much as the Galápagos Islands. Located off the coast of Ecuador, the Galapagos are a volcanic archipelago, or chain of islands. They began to take shape anywhere between 3 and 90 million years ago, but went unrecorded until 1535 CE, remaining uninhabited by humans until the 19th century. Over this vast period of time, some of the most unique animals on the planet evolved, cut off from the rest of the world by over 600 miles of ocean. 

The Galapagos Islands formed from repeated volcanic activity by submarine volcanoes and have a total of 24 active, dormant, and extinct volcanoes. There are 13 major islands, six small islands, and numerous islets. The islands get their name from their most famous animal—the Galapagos Tortoise, as galápago is a Spanish word meaning “turtle.” Volcanic, mountainous, rocky terrain defines the Galapagos Islands, and there are very few sources of fresh drinking water. These factors prevented permanent settlement by native South American and Polynesian tribes. To reach this renowned archipelago, prehistoric forms of waved albatross and Galapagos hawks would have flown; ancient sharks and sea lions would have swam; and land animals would have drifted there atop natural rafts of wood and vegetation on the currents of the Pacific Ocean. These land animals, in particular, found themselves stranded hundreds of miles from the coast of South America and forced to adapt to their harsh new home. A Galapagos lava lizard, for example, appears like a piece of smoldering molten rock, with gray and black scales down its back and vibrant orange on its face. But the more fascinating case lies in the marine iguana, the only remaining lizard species that can live and feed in the ocean. Their aquatic abilities came as a result of evolution, as scientists believe that they are descended from the same ancestor as endemic, or native, ground iguanas. They began dwelling in intertidal and subtidal zones and, because of how limited sources of food are, eating the red and green algae that grow there. The native Galapagos sea lion, one of the smallest species of sea lion in the world, are more accustomed to life on land than most sea lion species. This is likely due to the islands' remoteness. 

The distance from the mainland meant that birds had the easiest time making the long journey to the Galapagos. A staggering 130 species of birds call the islands home, 30 of which only exist on the Galapagos! There are pelicans, albatrosses, crakes, and flightless cormorants. Few are more well-known than the Galapagos penguin, the only species of penguin that lives north of the equator! But none are as impactful on modern science as the various breeds of finches found across the islands. When Charles Darwin visited the Galapagos Islands in 1835, he noticed differences in the size, shape, and color of the beaks of these finches depending on which island or area they lived in. This discovery served as a foundational piece in his theory of evolution—that animals develop traits unique to their habitat. Darwin’s finches and all of the other animals on the Galapagos Islands provided ample evidence for this theory, transforming our perception of nature and our own history as a species.

The uniqueness of the islands’ wildlife, combined with increased human interaction, has led to many species on the Galapagos becoming endangered. This includes the Galapagos tortoise, penguins, sea lions, and flightless cormorants. Unaccustomed to humans, these animals and others showed no fear at our presence, making them easy sources of food for passing voyages and whaling vessels that stopped on the islands. Several organizations are dedicated to protecting the one-of-a-kind wildlife on the Galapagos Islands, including the Galapagos Conservancy and the Galapagos Conservation Trust. Without awareness and assistance, some of the most pivotal and special species on the planet could be lost forever.

As life rapidly trots, dashes, and glides through fall, one species—our spotlight species for this month—is content with a slow and deliberate crawl. That species would be the Galapagos Tortoise! Focusing our attention on the Ecuadorian volcanic archipelago this month, it feels apt that we make space for the Galapagos islands’ namesake; galápago, a term given by the Spanish conquistadors meaning “tortoise.” Galapagos Tortoises are one of the Earth’s gentle giants and a species that has an incredibly unique natural history. Around two million years ago a classic case of genetic drift led to a few tortoises, presumably the Chaco Tortoise of South America, floating away on vegetation mats and by chance making landfall on several islands off the coast of Ecuador. From here the survivors faced a suite of novel environmental factors unique to the islands which facilitated a new phase of natural selection. This gene selection led to some tortoises growing longer necks, and others with shorter necks. Some tortoises had a saddle-back shell–aiding in reaching higher vegetation–and others with domed shells ideal for grassy ecosystems where vegetation is easily accessible.

The commonality between all fourteen subspecies of Galapagos Tortoises is the iconic gigantism, a not so uncommon trait for island-dwelling species caused by a lack of predation due to the isolated nature of the islands. Unfortunately for the island tortoises, their isolation was destined to end with the arrival of Spanish explorers conquering every corner of the Americas, including the islands. Their arrival may have brought invasive species such as rats, which increased competition. According to an article in biological conservation, populations declined from two hundred and fifty thousand to fifteen thousand by 1970, insinuating that the tortoises were even hunted by humans for their shells and meat. In fact, three of the Galapagos Tortoise species have now gone extinct and the rest are highly endangered. Due to habitation loss from agriculture and irreparable damage directly done by humans, conservation efforts for these species are in full swing. As a keystone species, the fate of not just Galapagos Tortoises are in our hands, but that of countless species that depend on them for environmental functions such as seed dispersal, bird perching, and trampling of overgrowth allowing new seedlings to receive light.

All life on Earth deserves to flourish, but there is something to be said about this species who has lived peacefully for millions of years without predators, estimated to reach the age of at least 100 years old in the wild. Just by engaging in this article we are creating a platform for these gentle giants to plead their case and expand conservation efforts through educational outreach. We hope you learned something new this month about the Galapagos Islands and their inhabitants and are inspired to share its story!

When we think of volcanoes, we might imagine rocks shooting into the air, lava pouring over the earth, and dark clouds filling the sky. But volcanoes don’t have to be as explosive as we think.

In simple terms, a volcano is the release of magma (or molten rock) from beneath the Earth’s surface due to tectonic movement. These releases don’t have to be sudden, violent, gigantic eruptions, and they don’t have to occur on terrestrial land! In fact, there are numerous, widespread systems of submarine volcanoes - or volcanoes underwater on the ocean floor!

Submarine volcanoes typically occur in three different geological settings: subduction zones, ocean ridges (or spreading centers), and hot spots (or mantle plumes). At subduction zones, one tectonic plate is pushed below, or subducted beneath the other, allowing subterranean molten rock or magma to push up to the surface. At ocean ridges, tectonic plates pull apart and lava rises to fill the gap and cools, adding to the earth’s crust. Lastly, hot spots are areas in the middle of tectonic plates (as opposed to along a plate boundary) where plumes of hot magma rise up. This hot magma rises and becomes a plume because the magma is hotter, and therefore less dense, than the surrounding material. 

Connecting to our Species Spotlight on the Galapagos Turtle, the Galapagos Islands are one example of an island chain formed by submarine volcanoes. The Galapagos Islands were formed due to a hot spot or “mantle plume” underneath the Earth’s surface that the Nazca tectonic plate moved eastward over. Due to the direction of the plate’s movement, the islands are formed in a progression; the oldest islands are the easternmost islands, and the youngest islands are the westernmost islands. The majority of the islands in the Galapagos chain have a conical shape, formed due to many successive magma eruptions. These eruptions result in stacked, cooled layers of lava that build up the islands’ steep slopes.