The mystique of the Galapagos Islands

dvm360dvm360 May 2023
Volume 54
Issue 5
Pages: 77

How several species have made fascinating adaptions to the environment and anecdotes from a local tour guide

Rene /

Rene /

Rafael Pesantes, a tour guide on the Galapagos Islands, calls this land a "magicial place."1 Indeed, it's Charles Darwin's On the Origin of Species unfolding before your eyes. Terms you might remember from biology class, such as natural selection, are living and breathing around you.

Pesantes is greatly a self-taught naturalist. He has participated in several published, peer-reviewed scientific papers and, for 35 years, has given thousands of individuals tours of various wondrous places worldwide. He once toured the Galapagos with famed British naturalist and TV host David Attenborough.

As a Galapagos native, Pesantes is not shy about expressing the special love in his heart for the archipelago off the west coast of Ecuador. So what makes this place so magical and especially appealing to science geeks? Pesantes provided examples of some specific species and their unique adaptive features and firsthand experiences of the wildlife as a tour guide to set the scene.

The incredible species of the Galapagos

Having a special interest in ornithology, Pesantes highlighted the 13 species of Galapagos finches, or Darwin’s finches.2 The Galapagos finches are a classic example of an adaptive radiation, the relatively rapid evolution of ecologically different species from 1 common ancestor. Comparisons of anatomical features of the Galapagos finches, as well as modern molecular techniques, show they are a monophyletic group, a group of organisms all descended from 1 ancestral species. The finches adapted and developed different feeding habits and looks, dependent on where they were.

Meanwhile, Galapagos flightless cormorants3 are a single species which, over time, lost their need to fly, as all their food is found on the islands of Isabela and Fernandina and they have virtually no land predators.

Another example is the famous Galapagos giant tortoise,4 of which there are 14 species (according to most sources) that like the finches, all came from a single species. Their species variation is greatly dependent on the food source of the island they live on. For example, several Galapagos tortoise species have a saddle-backed carapace and have evolved an upward curve in the front of the carapace, which allows them to stretch to reach higher-growing plants. For those more interested in the tortoises, the Galapagos Tortoise Movement Ecology Program5 and the Charles Darwin Research Station6 study the reptiles.

Although pirates no longer hunt the giant tortoises, their young and even their eggs may be attacked by feral cats. As in many places around the world, there’s controversy here: Should these cats be culled, or is it a better option to trap, neuter, vaccinate, then return them? Veterinarians from the United States and Canada have participated in spay/neuter programs on the islands, mostly for feral cats but also for owned cats. Animals on the islands, ranging from lava lizards to those flightless cormorants, have no defense against feral cats.

Arguably, a more significant concern are humans—the very ecotourists who infuse money into Ecuador and are important to the Galapagos economy. Cruise boats that bring more than 100 individuals to the islands have, over time, impacted them. Today, no more than 100 individuals are allowed on a vessel. “Taking a smaller vessel is always a better experience anyway,” Pesantes said. “You are more flexible and avoiding larger crowds, you are often able to see more in the water and on land.”1

Anecdotes from the Galapagos tour guide

Pesantes explained that sometimes the experiences on a vessel can be surprising. One time, he and his group were snorkeling and watching sea turtles when suddenly a pod of orcas appeared. “It happened so fast, but I could see they were clearly docile. Still, I [must] say the adrenaline [did] rush with so many killer whales all around us. I admit 1 person flew out of the water [and jumped] back into the Zodiac [boat]. Everyone else, though, just circled around me for a once-in-a-lifetime experience."1

On another occasion, Pesantes and his group were observing blue-footed booby birds diving into the ocean, fishing among a giant school of sardines, when suddenly another group of fishermen appeared: blacktip sharks. One tourist was so excited to see the sharks that he dived in from the Zodiac. “He just as quickly jumped right back into the boat.” It was OK; the sharks were interested only in the sardines.

Pesantes gives tours in many locations around the world but called the Galapagos “a very special place.”

“Not only are there many species in the Galapagos with unique adaptations you will not find anywhere else in the world, but most of the animals also aren’t afraid of humans,” he said. “Here, they’ve never been hunted and have no reason to fear, so we can get very close.”1

Steve Dale, CABC, writes for veterinary professionals and pet owners, hosts 2 national radio programs, and has appeared on TV shows, including Good Morning America and The Oprah Winfrey Show. He is on the dvm360 Editorial Advisory Board as well as the boards of the Human Animal Bond Association and EveryCat Foundation. He appears at conferences around the world. Visit


  1. Learn about the beauty of the Galapagos Islands. Steve Dale’s Other World. WGN Radio 720. February 22, 2023. Accessed April 6, 2023. wgn-plus/steve-dales-other-world/learn-about-the-beauty-of-the-galapagos-islands
  2. Darwin’s finches. Galapagos Conservation Trust. Accessed April 3, 2023. https://
  3. Flightless cormorant. Galapagos Conservation Trust. Accessed April 3, 2023.
  4. Galapagos giant tortoise. Galapagos Conservation Trust. Accessed April 3, 2023.
  5. Tracking giants. Galapagos Tortoise Movement Ecology Program. Accessed April 3, 2023.
  6. Charles Darwin Research Station. Charles Darwin Foundation. Accessed April 3, 2023.
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