The HMS Beagle sails past Isolte Tortuga on September 28, with Darwin making many notes aout the flora, fauna, and terrain.
Darwin is shocked at the abundance of marine iguanas. These great lizards have no fear of humans, and prefer to sunbathe on the rocks rather than retreat from potential danger.
The marine iguana is found throughout the Galapagos, and it remains the only lizard that is able to feed in the sea. With few natural predators, the marine iguana was unable to cope with the introduction of species like cats and dogs, and saw numbers decline drastically when the islands were colonized by humans. Visitors often remark at how close the lizards will allow them to get before turning away, a trait which no longer works in their favor.