age aged aldabra giant tortoise aldabrachelys gigantea armor armored armorment armour armoured armourment carapace eating eating grass elongated neck giant tortoise herbivore hide large tortoise leathery longevity neck old plod plodding protection protective reptile reptilian Seychelles shell size skin slow strength strong texture textured textures tortoise zoo abstract appearance aldabra-giant-tortoise aldabrachelys-gigantea eating-grass giant-tortoise large-tortoise moist mouth open-mouthed tongue brown colors colours contours cover exterior grooves hard horny-plates layers lined lines outlines pointed points shelter solid tough