Bryan and Cherry Alexander / Galapagos giant tortoise (Geochelone elephantophus porteri) grazing in habitat. Santa Cruz, Galapagos, January.

Richard Du Toit / Leopard Tortoise (Geochelone pardalis) baby walking on road, Northern Cape, South Africa

Brent Stephenson / Ploughshare Tortoise or Angonoka (Astrochelys / Geochelone yniphora) on the side of a track showing the upturned projection this animal gets its name from. A radio-transmitter aerial can be seen proje...

Pete Oxford / Radiated Tortoise (Geochelone radiata), native to Madagascar

Pete Oxford / Radiated Tortoise (Geochelone radiata), native to Madagascar

Staffan Widstrand / Captive tortoises (Chelonia nigra) at Charles Darwin Research Station. Galapagos, Ecuador, April.

Staffan Widstrand / Galapagos Giant Tortoise (Chelonoidis nigra) walking past grass. Santa Cruz Island, Galapagos, Ecuador, April.

Staffan Widstrand / Head of a Galapagos Giant Tortoise (Chelonoidis nigra) in profile. Santa Cruz Island, Galapagos, Ecuador, April.

Staffan Widstrand / Galapagos Giant Tortoise (Chelonoidis nigra) yawning. Captive. Santa Cruz Island, Galapagos, Ecuador, April.

Staffan Widstrand / Close-up of a Galapagos Giant Tortoise (Chelonoidis nigra) foot and claws. Captive. Santa Cruz Island, Galapagos, Ecuador, April.

Tui De Roy / Leopard Tortoise (Geochelone pardalis), Mpala Research Centre, Kenya

Tui De Roy / Leopard Tortoise (Geochelone pardalis), Mpala Research Centre, Kenya

Pete Oxford / Saddleback Galapagos Tortoise (Chelonoidis nigra hoodensis), Wolf Volcano, Isabella Island, Galapagos Islands, Ecuador

Pete Oxford / Saddleback Galapagos Tortoise (Chelonoidis nigra hoodensis) retracted in shell, base of Sierra Negra, Isabella Island, Galapagos Islands, Ecuador

Pete Oxford / Galapagos Giant Tortoise (Chelonoidis nigra) baby in burrow, Wolf Volcano, Isabella Island, Galapagos Islands, Ecuador

Pete Oxford / Galapagos Giant Tortoise (Chelonoidis nigra) young being injected with PIT tag, Wolf Volcano, Isabella Island, Galapagos Islands, Ecuador

Pete Oxford / Saddleback Galapagos Tortoise (Chelonoidis nigra hoodensis) resting in the depression of shell, Wolf Volcano, Isabella Island, Galapagos Islands, Ecuador

Pete Oxford / Saddleback Galapagos Tortoise (Chelonoidis nigra hoodensis) young, Wolf Volcano, Isabella Island, Galapagos Islands, Ecuador

Pete Oxford / Saddleback Galapagos Tortoise (Chelonoidis nigra hoodensis) foot, Wolf Volcano, Isabella Island, Galapagos Islands, Ecuador

Pete Oxford / Galapagos Giant Tortoise (Chelonoidis nigra) foot, Wolf Volcano, Isabella Island, Galapagos Islands, Ecuador

Pete Oxford / Saddleback Galapagos Tortoise (Chelonoidis nigra hoodensis) male, Wolf Volcano, Isabella Island, Galapagos Islands, Ecuador

Pete Oxford / Indefatigable Island Tortoise (Chelonoidis nigra porteri) and Domestic Cattle (Bos taurus), Santa Cruz Island, Galapagos Islands, Ecuador

Pete Oxford / Indefatigable Island Tortoise (Chelonoidis nigra porteri) and Domestic Cattle (Bos taurus), Santa Cruz Island, Galapagos Islands, Ecuador

Pete Oxford / Indefatigable Island Tortoise (Chelonoidis nigra porteri) and Domestic Cattle (Bos taurus) group, Santa Cruz Island, Galapagos Islands, Ecuador

Pete Oxford / Indefatigable Island Tortoise (Chelonoidis nigra porteri) and Domestic Cattle (Bos taurus), Santa Cruz Island, Galapagos Islands, Ecuador

Hiroya Minakuchi / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) eating grass, Alcedo Volcano, Isabella Island, Galapagos Islands, Ecuador

Hiroya Minakuchi / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) foot, Alcedo Volcano, Isabella Island, Galapagos Islands, Ecuador

Hiroya Minakuchi / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) basking, Alcedo Volcano, Isabella Island, Galapagos Islands, Ecuador

Pete Oxford / Galapagos Giant Tortoise (Geochelone elephantophus / Chelonoidis nigra) Charles Darwin Research Station. Puerto Ayora,Santa Cruz Island, Galapagos, endemic

Pete Oxford / Galapagos Giant Tortoise (Geochelone elephantophus / Chelonoidis nigra) head portrait, Charles Darwin Research Station. Puerto Ayora,Santa Cruz Island, Galapagos, endemic

Pete Oxford / Close up of the foot pad of a Galapagos Giant Tortoise (Geochelone elephantophus / Chelonoidis nigra) Charles Darwin Research Station. Puerto Ayora,Santa Cruz Island, Galapagos, endemic

Pete Oxford / Galapagos Giant Tortoise, Saddleback form (Geochelone elephantophus hoodensis / Chelonoidis nigra hoodensis) Charles Darwin Research Station, Puerto Ayora, Santa Cruz Island, Galapagos

Pete Oxford / Galapagos Giant Tortoise, Saddleback form (Geochelone elephantophus hoodensis / Chelonoidis nigra hoodensis) Charles Darwin Research Station, Puerto Ayora, Santa Cruz Island, Galapagos

Christophe Courteau / Leopard tortoise (Geochelone pardalis) swimming through flood water, Okavango Delta, Botswana, March.

Pete Oxford / Galapagos Giant Tortoise (Chelonoidis nigra), Charles Darwin Research Station, Puerto Ayora, Santa Cruz Island, Galapagos Islands, Ecuador

Pete Oxford / Galapagos Giant Tortoise (Chelonoidis nigra), Charles Darwin Research Station, Puerto Ayora, Santa Cruz Island, Galapagos Islands, Ecuador

Pete Oxford / Pinzon Island Tortoise (Chelonoidis nigra ephippium) hatchling emerging from egg, Charles Darwin Research Station, Puerto Ayora, Santa Cruz Island, Galapagos Islands, Ecuador

Pete Oxford / Pinzon Island Tortoise (Chelonoidis nigra ephippium) hatchling emerging from egg, Charles Darwin Research Station, Puerto Ayora, Santa Cruz Island, Galapagos Islands, Ecuador

Pete Oxford / Pinzon Island Tortoise (Chelonoidis nigra ephippium) hatchling emerging from egg, Charles Darwin Research Station, Puerto Ayora, Santa Cruz Island, Galapagos Islands, Ecuador

Pete Oxford / Pinzon Island Tortoise (Chelonoidis nigra ephippium) hatchling emerging from egg, Charles Darwin Research Station, Puerto Ayora, Santa Cruz Island, Galapagos Islands, Ecuador

Pete Oxford / Yellow-footed Tortoise (Geochelone denticulata) in leaf litter, Napo River, Yasuni National Park, Amazon, Ecuador

Pete Oxford / Yellow-footed Tortoise (Geochelone denticulata), Iwokrama Rainforest Reserve, Guyana

Pete Oxford / Yellow-footed Tortoise (Geochelone denticulata), Iwokrama Rainforest Reserve, Guyana

Inaki Relanzon / Ploughshare / Angonoka tortoise (Geochelone yniphora), one of the most endangered turttles in the world, Baie de Baly National Park, North west Madagascar.

Inaki Relanzon / Tracking system attached to a Ploughshare / Angonoka tortoise (Geochelone yniphora), one of the most endangered turttles in the world, Baie de Baly National Park, North west Madagascar.

Inaki Relanzon / Member of the Durrell Conservation Trust taking care of Ploughshare / Angonoka tortoise (Geochelone yniphora) one of the most endangered turtles in the world, Baie de Baly National Park, North west Ma...

Pete Oxford / Galapagos Giant tortoise (Geochelone elephantophus vandenburghi) grazing on rim of crater, Alcedo Volcano, Isabela Island Galapagos islands, Ecuador, South America

Pete Oxford / Galapagos Giant tortoise (Geochelone elephantophus vandenburghi) on rim of crater, with fumaroles behind (emitting steam and gas) Alcedo Volcano, Isabela Island, Galapagos islands, Ecuador, South Amer...

Pete Oxford / Galapagos Giant tortoises (Geochelone elephantophus vandenburghi) in crater of Alcedo Volcano, Isabela Island, Galapagos islands, Ecuador, South America

Pete Oxford / Pair of Galapagos Giant tortoises (Geochelone elephantophus vandenburghi) mating Alcedo Volcano crater floor, Isabela Island Galapagos islands, Ecuador, South America

Pete Oxford / Galapagos Giant tortoise (Geochelone elephantophus vandenburghi) and fumaroles (emitting steam and gas) Alcedo Volcano, Isabela Island, Galapagos islands, Ecuador, South America

Pete Oxford / Galapagos Giant tortoise (Geochelone elephantophus vandenburghi) on rim of Alcedo Volcano, Isabela Island, Galapagos islands, Ecuador, South America

Pete Oxford / Galapagos Giant tortoise (Geochelone elephantophus vandenburghi) near steam vent, Alcedo Volcano crater floor, Isabela Island Galapgos islands, Ecuador, South America

Pete Oxford / Head portrait of a Galapagos Giant tortoise (Geochelone elephantophus vandenburghi) in water, Alcedo Volcano, Isabela Island Galapagos islands, Ecuador, South America

Pete Oxford / Two pairs of Galapagos Giant tortoises (Geochelone elephantophus vandenburghi) mating Alcedo Volcano crater floor, Isabela Island Galapagos islands, Ecuador, South America

ZSSD / Galapagos Giant Tortoise (Chelonoidis nigra), native to the Galapagos Islands, Ecuador

ZSSD / Galapagos Giant Tortoise (Chelonoidis nigra) portrait, native to the Galapagos Islands, Ecuador

Tui De Roy / Volcan Wolf Tortoise (Chelonoidis nigra becki), Galapagos Islands, Ecuador

Tui De Roy / Volcan Wolf Tortoise (Chelonoidis nigra becki) having blood taken for DNA analysis, this subspecies shows genetic markers from Pinta and Floreana Island subspecies, Galapagos Islands, Ecuador

Tui De Roy / Volcan Wolf Tortoise (Chelonoidis nigra becki), Galapagos Islands, Ecuador

Tui De Roy / Volcan Wolf Tortoise (Chelonoidis nigra becki), Galapagos Islands, Ecuador

Tui De Roy / Volcan Wolf Tortoise (Chelonoidis nigra becki), Galapagos Islands, Ecuador

Tui De Roy / Pinta Island Galapagos Tortoise (Chelonoidis nigra abingdoni) named Lonesome George is the last individual of his subspecies, Charles Darwin Research Center, Pinta Island, Galapagos Islands, Ecuador

Tui De Roy / Pinta Island Galapagos Tortoise (Chelonoidis nigra abingdoni) named Lonesome George is the last individual of his subspecies, browsing on cactus, Charles Darwin Research Station, Pinta Island, Galapag...

Tui De Roy / Pinta Island Galapagos Tortoise (Chelonoidis nigra abingdoni) named Lonesome George is the last individual of his subspecies, Charles Darwin Research Center, Pinta Island, Galapagos Islands, Ecuador

Tui De Roy / Pinta Island Galapagos Tortoise (Chelonoidis nigra abingdoni) named Lonesome George is the last individual of his subspecies, with attendant, Charles Darwin Research Center, Pinta Island, Galapagos Is...

Tui De Roy / Pinta Island Galapagos Tortoise (Chelonoidis nigra abingdoni) named Lonesome George is the last individual of his subspecies, Charles Darwin Research Station, Pinta Island, Galapagos Islands, Ecuador

Tui De Roy / Pinta Island Galapagos Tortoise (Chelonoidis nigra abingdoni) named Lonesome George is the last individual of his subspecies, Charles Darwin Research Station, Pinta Island, Galapagos Islands, Ecuador

Tui De Roy / Galapagos Giant Tortoise (Chelonoidis nigra) undergoing surgery to sterilize hybrids accidentally produced in captive breeding program to repopulate Pinta Island to restore its ecological balance, Cha...

Tui De Roy / Saddleback Galapagos Tortoise (Chelonoidis nigra hoodensis) captive-bred young awaiting release back onto their islands of origin, Galapagos Islands, Ecuador

Tui De Roy / Saddleback Galapagos Tortoise (Chelonoidis nigra hoodensis) captive-bred hatchling emerging from egg, Galapagos Islands, Ecuador

Tui De Roy / Saddleback Galapagos Tortoise (Chelonoidis nigra hoodensis) captive-bred hatchlings emerging from eggs, Galapagos Islands, Ecuador

Tui De Roy / Saddleback Galapagos Tortoise (Chelonoidis nigra hoodensis) captive-bred young are measured and branded in preparation for release back onto their islands of origin, Galapagos Islands, Ecuador

Tui De Roy / Saddleback Galapagos Tortoise (Chelonoidis nigra hoodensis) captive-bred hatchling emerging from egg, Galapagos Islands, Ecuador

Tui De Roy / Saddleback Galapagos Tortoise (Chelonoidis nigra hoodensis) named Diego, an old male returned to the Galapagos from the San Diego Zoo in 1977 and sire of large number of young in captive breeding prog...

Tui De Roy / Saddleback Galapagos Tortoise (Chelonoidis nigra hoodensis) named Diego, an old male returned to the Galapagos from the San Diego Zoo in 1977 and sire of large number of young in captive breeding prog...

Tui De Roy / Saddleback Galapagos Tortoise (Chelonoidis nigra hoodensis) named Diego, an old male returned to the Galapagos from the San Diego Zoo in 1977 and sire of large number of young in captive breeding prog...

Tui De Roy / Saddleback Galapagos Tortoise (Chelonoidis nigra hoodensis) named Diego, an old male returned to the Galapagos from the San Diego Zoo in 1977 and sire of large number of young in captive breeding prog...

Tui De Roy / Saddleback Galapagos Tortoise (Chelonoidis nigra hoodensis) captive-bred young awaiting release back onto its island of origin, Galapagos Islands, Ecuador

Tui De Roy / Galapagos Giant Tortoise (Chelonoidis nigra) portrait, Galapagos Islands, Ecuador

Tui De Roy / Galapagos Giant Tortoise (Chelonoidis nigra), Galapagos Islands, Ecuador

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) males in aggressive display, Isabella Island, Galapagos Islands, Ecuador

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) searching for water around steaming fumaroles during prolonged dry season, Isabella Island, Galapagos Islands, Ecuador

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) near fumarole, Isabella Island, Galapagos Islands, Ecuador

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) group wallowing in rain pool, Isabella Island, Galapagos Islands, Ecuador

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) male walking, Isabella Island, Galapagos Islands, Ecuador

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) male on caldera floor, Isabella Island, Galapagos Islands, Ecuador

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) pair, Isabella Island, Galapagos Islands, Ecuador

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) male with steaming fumaroles on caldera floor, Isabella Island, Galapagos Islands, Ecuador

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) feeding on grass, Isabella Island, Galapagos Islands, Ecuador

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) pair mating, Isabella Island, Galapagos Islands, Ecuador

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) wallowing in mud, Isabella Island, Galapagos Islands, Ecuador

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) pairs mating, Isabella Island, Galapagos Islands, Ecuador

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) mating, Isabella Island, Galapagos Islands, Ecuador

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) wallowing in seasonal rain pool, Isabella Island, Galapagos Islands, Ecuador