One of the most well-known Galápagos species is the giant land tortoise. It's also been one of the most endangered -- rats eat tortoise eggs, and goats ravenously clear out the vegetation the tortoises depend on. The Darwin Center is working to rebuild stable populations of the different species of giant land tortoise, and reintroduce them on the islands where they've become threatened or extinct. There is also a major effort to rid the islands of goats and rats.

A giant land tortoise in his natural element, on a ranch on Santa Cruz island.

Here are several baby giant tortoises being raised for eventual reintroduction to another island.

This is "Lonesome George". He's the only remaining member of his subspecies. They've put a couple females of another subspecies in his pen, but he hasn't shown any interest in mating with them.

This giant land tortoise was kept several years ago by a man who came home drunk one night and fired some rounds into his shell.

Even though giant land tortoises don't have any teeth, they seem to do OK eating this thick stalk with their gums. They could also rip your hand off.

Again, the familiar eyes.

Giant land tortoises mating.

The ranch had a few tortoise shells displayed.

The inside of the tortoise shell.

A sea turtle swimming next to the boat.

A sea turtle swimming in a tidepool.

On to Sally Lightfoot Crabs