Tui De Roy / Darwin's small ground finch (Geospiza fuliginosa), inspecting Galapagos giant tortoise for ticks, Isabela Island, Galapagos, South America.

Tui De Roy / Galapagos hawk (Buteo galapagoensis) landing on mating pair of Galapagos giant tortoise (Chelonoidis vandenburgh) Alcedo Volcano, Isabela Island, Galapagos.

Tui De Roy / Alcedo giant tortoise (Chelonoidis vandenburghi), Alcedo Volcano, Isabela Island, Galapagos

Tui De Roy / Alcedo giant tortoise (Chelonoidis vandenburghi), Alcedo Volcano, Isabela Island. This is where the largest extant population exists, acting as ecosystem engineers by maintaining open meadows and digg...

Tui De Roy / Wolf giant tortoise (Chelonoidis becki) two males fight briefly over mating rights. Wolf Volcano, Isabela Island, Galapagos

Tui De Roy / Wolf giant tortoise (Chelonoidis becki) in habitat. Hybrids of mixed parentage with different shell shapes are scattered far and wide on the rugged west slope of Wolf Volcano. Wolf Volcano, Isabela Is...

Shane Gross / Galapagos green sea turtles (Chelonia mydas agassizii) feeding on seaweed growing on lava rocks off Isabela Island, Galapagos, Ecuador. December.

Lucas Bustamante / Sierra Negra giant tortoise (Chelonoidis guntheri) Isabela Island, Galapagos Islands.

John Shaw / Yellow warbler (Setophaga petechia aureola) on lava rocks. Isabela Island, Galapagos. May.

Nick Hawkins / Galapagos sea lion (Zalophus wollebaeki), three resting underneath school bus. Isabela Island, Galapagos. 2017.

Nick Hawkins / Marine iguana (Amblyrhynchus cristatus) basking on volcanic rock at coast. Isabela Island, Galapagos.

Nick Hawkins / Sergeant major (Abudefduf sp) schooling in mangroves of Isabela Island, Galapagos.

Tui De Roy / Blue-footed booby (Sula nebouxii) landing. Punta Vicente Roca, Isabela Island, Galapagos.

Tui De Roy / Blue-footed booby (Sula nebouxii) coming in to land. Punta Vicente Roca, Isabela Island, Galapagos.

Tui De Roy / Alcedo giant tortoises (Chelonoidis vandenburghi) group resting in water on moonlit night to keep cool, Alcedo Volcano, Isabela Island, Galapagos

Tui De Roy / Alcedo giant tortoise (Chelonoidis vandenburghi) walking, Alcedo Volcano, Isabela Island, Galapagos

Tui De Roy / Alcedo giant tortoise (Chelonoidis vandenburghi) pair mating in shallow pool, with two others resting nearby. Alcedo Volcano, Isabela Island, Galapagos

Tui De Roy / Marine iguana (Amblyrhynchus cristatus), Punta Vicente Roca, Isabela Island, Galapagos

Tui De Roy / Marine iguanas (Amblyrhynchus cristatus) fighting, Punta Vicente Roca, Isabela Island, Galapagos

Tui De Roy / Marine iguanas (Amblyrhynchus cristatus) silhouettes at sunset, Punta Vicente Roca, Isabela Island, Galapagos

Tui De Roy / Marine iguana (Amblyrhynchus cristatus) on shore, Punta Moreno, Isabela Island, Galapagos

Tui De Roy / Green turtle (Chelonia mydas), female returning to the sea after egg laying, Puerto Pajas, Isabela Island, Galapagos

Tui De Roy / Alcedo giant tortoise (Chelonoidis vandenburghi) silhouetted at sunrise, Alcedo Volcano, Isabela Island, Galapagos

Tui De Roy / Alcedo giant tortoise (Chelonoidis vandenburghi) group resting in pool, Alcedo Volcano, Isabela Island, Galapagos

Tui De Roy / Alcedo giant tortoise (Chelonoidis vandenburghi) group resting in water at night, Alcedo Volcano, Isabela Island, Galapagos

Tui De Roy / Alcedo giant tortoise (Chelonoidis vandenburghi) male mating with female while squabbling with another tortoise. Alcedo Volcano, Isabela Island, Galapagos

Andy Rouse / Alcedo volcano Galapagos giant tortoise (Chelonoidis vandenburghi) adult male on forest track, Urbina Bay, Isabela Island, Galapagos.

Tui De Roy / Galapagos sea lion (Zalophus wollebaeki) killing tuna. A group of the sea lion bulls have learnt to herd Pelagic yellowfin tuna into a small cove, trapping them. The fish often leap ashore in an effor...

Tui De Roy / Galapagos sea lion (Zalophus wollebaeki) hunting tuna. A group of the sea lion bulls have learnt to herd Pelagic yellowfin tuna into a small cove, trapping them. The fish often leap ashore in an effor...

Tui De Roy / Galapagos sea lion (Zalophus wollebaeki) hunting tuna. A group of the sea lion bulls have learnt to herd Pelagic yellowfin tuna into a small cove, trapping them. The fish often leap ashore in an effor...

Tui De Roy / American flamingo (Phoenicopterus ruber) group of four with one displaying Punta Moreno, Isabela Island, Galapagos

Tui De Roy / Galapagos penguin (Spheniscus mendiculus) Isla Tortuga, Isabela Island, Galapagos

Andy Rouse / Galapagos land iguana (Conolophus subcristatus) walking towards camera, Urbina Bay, Isabela Island, Galapagos.

Andy Rouse / Galapagos land iguana (Conolophus subcristatus) feeding, Urbina Bay, Isabela Island, Galapagos.

Tui De Roy / Flightless cormorant (Phalacrocorax harrisi) underwater, Punta Vicente Roca, Isabela Island, Galapagos, Ecuador, April.

Tui De Roy / Fissure eruption of Chico Volcano into 9km diameter caldera. Sierra Negra volcano, Isabela Island, Galapagos, Ecuador. October 2005.

Tui De Roy / People watching the Fissure eruption of Chico volcano into 9km diameter caldera. Sierra Negra volcano, Isabela Island, Galapagos, Ecuador. October 2005.

Tui De Roy / Volcan Alcedo giant tortoises (Chelonoidis nigra vandenburghi) wallowing in rain pools on caldera floor, possibly for thermoregulation or detering parasites, with sulphur fumaroles in background, Alce...

Tui De Roy / Wolf-Volcano giant tortoise (Chelonoidis nigra becki) portrait with ground finch (Geospiza sp. ) sitting on foot, Isabela Island, Galapagos. Did you know? Galapagos tortoises have a mutualistic relati...

Tui De Roy / Wolf Volcano giant tortoise (Chelonoidis nigra becki) portrait, Isabela Island, Galapagos

Tui De Roy / Galapagos penguins (Spheniscus mandiculus) standing on coastal volcanic rock. Endangered. Isabela Island, Galapagos, Ecuador, June.

Tui De Roy / Flightless Cormorant (Nannopterum / Phalacrocorax harrisi) with nesting material. Banks Bay, Isabela Island, Galapagos Islands, Ecuador, December.

Tui De Roy / Flightless Cormorant (Nannopterum / Phalacrocorax harrisi) with chick at nest, made from dead starfish. Banks Bay, Isabela Island, Galapagos Islands, Ecuador, December.

Pete Oxford / Saddleback form of Galapagos Giant Tortoise (Chelonoidis nigra) walking, Wolf Volcano, Isabela Island, Galapagos

Juan Carlos Munoz / View from the caldera rim of the Chico Volcano, Sierra Negra, Isabela Island, Galapagos, January 2009

Juan Carlos Munoz / Greater flamingo {Phoenicopterus ruber} feeding in coastal lagoon, Isabela Island, Galapagos, January

Andy Rouse / Galapagos land iguana (Conolophus subcristatus) walking, Urbina Bay, Isabela Island, Galapagos (non-ex)

Pete Oxford / Galapagos Giant Tortoise (Geochelone elephantophus vandenburghi) near fumaroles, Alcedo Volcano crater floor, Isabela Island, Galapagos Islands