A local customer here in San Diego owns 2 mastifs and one large, old tortoise that he inherited from his parents. Tortoises dig long, deep burrows for shelter from the heat.

The husband received a franic call one afternoon from his wife saying that one of the mastifs was missing. He came home and he and his wife, jumped in separate cars and started driving through their rural neighbood looking for the dog.  His wife called him an hour later to return home-- she'd found the dog! Where was the dog? The dog had crawled into the tortoise's burrow and the tortoise back in after, trapping the dog's exit.  Only when his wife went home after not finding the dog in the neighborhood, did she hear faint wimpering from their large yard.

She and her husband were able to coax the tortoise out of the burrow with some leafy treats, freeing the dog. They now keep the tortoise in a separate area.