Today we investigated the interface of the desert and the sea. At El Cardonal on Isla Partida the mangroves are literally just a few feet away from stately cardón and prickly cholla cacti. Some of us climbed the hillsides and were rewarded with magnificent views of the bay and the other side of the island. Kayaks and stand-up paddleboards were also options for those who wanted to explore more at water level. The denizens of the desert left many signs for us to discover. Ringtail cats, members of the raccoon family, had left tracks along the mangrove edges; jackrabbits had chewed extensively on the base of the cardón cactus; and crabs had drilled a multitude of holes all around the mangrove roots, shelters from desiccation and predators.  For the afternoon we jumped into the water with California sea lions and time flew by as quickly as the sea lions did. We returned to the National Geographic Sea Bird with that “happy tired” feeling of a day well spent investigating the intricacies of the Sonora desert and the underwater realm of the Sea of Cortez.