David Perpinan / Radiography of a Spider tortoise (Pyxis arachnoides) showing a characteristic of this species - they just lay one egg. Captive. Small repro only.

Chien Lee / Spider Tortoise (Pyxis arachnoides) in forest, Berenty Private Reserve, Madagascar

ZSSD / Spider Tortoise (Pyxis arachnoides) baby, native to Madagascar

Niall Benvie / Composite of insects, arachnids and plants found on the Arnos Vale BioBlitz, Bristol, UK, June 2012 meetyourneighbours.net project. Orange ladybird (Halyzia sedecimguttata), Ivy (Hedera helix), Green...

Pete Oxford / Flat-backed Spider Tortoise (Pyxis planicauda) camouflaged on ground, native to Madagascar

Pete Oxford / Flat-backed Spider Tortoise (Pyxis planicauda), native to Madagascar

Pete Oxford / Spider Tortoise (Pyxis arachnoides), native to Madagascar

Alan Watson / Spider / Flat tailed tortoise (Pyxis arachnoides) in spiny forest, Reniala Reserve, SW Madagascar, Critically endangered

Pete Oxford / Spider / Flat tailed tortoise (Pyxis arachnoides arachnoides) in 'spiny' forest between Itampolo village and entrance to Tsimanampetsotsa Reserve in south-west MADAGASCAR, endemic

Pete Oxford / Spider / Flat tailed tortoise (Pyxis arachnoides arachnoides) in 'spiny' forest between Itampolo village and entrance to Tsimanampetsotsa Reserve in south-west MADAGASCAR, endemic

Pete Oxford / Spider Tortoise (Pyxis arachnoides) left, and Radiated Tortoise (Geochelone radiata) right, carapace comparison, in tortoise repatriation animals confiscated from pet trade, Mangily, Madagascar

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) dew laden spider webs around fumarole vents, caldera rim, Alcedo Volcano, Isabella Island, Galapagos Islands, Ecuador

ZSSD / Spider Tortoise (Pyxis arachnoides) critically endangered species native to Madagascar

Pete Oxford / Flat-backed Spider Tortoise (Pyxis planicauda) retreated in shell, native to Madagascar

Joel Sartore / Photo Ark / Northern spider tortoise (Pyxis arachnoides brygooi) baby, being held in a hand, Indianapolis Zoo. Captive, occurs in Madagascar. Critically endangered.

Joel Sartore / Photo Ark / Two Northern spider tortoises (Pyxis arachnoides brygooi) adult and baby, portrait, Indianapolis Zoo. Captive, occurs in Madagascar. Critically endangered.

Joel Sartore / Photo Ark / Northern spider tortoise (Pyxis arachnoides brygooi) baby held in hand, Indianapolis Zoo. Captive, occurs in Madagascar. Critically endangered.

Joel Sartore / Photo Ark / Two Northern spider tortoises (Pyxis arachnoides brygooi) adult and baby, portrait, Indianapolis Zoo. Captive, occurs in Madagascar. Critically endangered.