When British naturalist Charles Darwin arrived in the Galápagos Islands in 1835, he was already four years into a round-the-world voyage aboard the survey ship HMS Beagle. His observations on the remote volcanic islands in the eastern Pacific Ocean would help him to develop his famous theory of evolution through natural selection. While studying the creatures here, he concluded that many South American species, mainly reptiles and birds that could cross the vast expanse of water, had migrated to the Galápagos and gradually adapted to their surroundings.

Among animals Darwin encountered were Galápagos giant tortoises, like those featured on our homepage. They grow up to 5 feet in length but have different shaped shells, depending on which island they inhabit. The islands are named after these magnificent creatures, 'galápago' meaning freshwater tortoise in Spanish. Today, on International Darwin Day, let's celebrate these gentle giants, which contributed to one of the great scientific discoveries of the 19th century.