Gopheroidus opuntiphilis — the Cactoise.

A future descendant of the Sonoran desert tortoise, perhaps 10 or 25 million years from today, which has co-evolved with a species of prickly pear cactus. It uses the cactus for shade, food and camouflage, and the cactus gets its seeds dispersed over a wide area and fertilized by the tortoise’s dung.

In the dry season, the tortoise digs a shallow burrow or pallet to stay cool, and hibernates. During this time the roots of the cactus may extend into the surrounding soil. When rains return, the tortoise may require two or three days to wake up and free itself from the binding roots, which gives the cactus ample time to replenish its water supply.

These tortoises still have a similar diet to their modern ancestors, eating all manner of desert plants including the pads, fruits and flowers of their own cactus partners. They maintain the size and shape of their shell “garden” by preening, shaking and rubbing to remove excess plant material. They are also semi-social and may prune or taste each others’ cactus when getting acquainted. Males are frequently seen following females for several days, nipping at their hindquarters–researchers presume this is to clear a space to mount the female, and perhaps the ritual is also part of the courtship.

When resting or hiding from danger, they retract their heads and forelegs against their shells. Millions of years of natural selection have shaped each species’ limbs to blend in with its particular species of symbiote cactus–as seen here. The tortoise’s “spines” are not really thorny, but leathery and flexible–but the illusion convinces most would-be predators not to bother.