We left for the Isla del Caņo, 20 km offshore, around 7:30 a.m. Our guide for the day, Javier, led us down to the dock and a small boat, which we boarded with our driver, Carlos, and another couple from the lodge. The boat was light in front, and shot off waves with a smack. Pencil-sized flying fish skimmed out in front of us.

About midway through the crossing, we ran into a huge black rain cloud, which cooled things down a little but ended before we arrived at the island. Carlos tried to drive around the cloud without much success. From the mainland, the island looked like a rectangular box rising out of the ocean, with closely cropped jungle on top and sheer cliffs at both ends.

We made a wet landing in the surf and carried our gear to a picnic table, then visited the Ranger Station. We washed our feet in a small cement box filled with water, then climbed the cement stairs to the painted brown deck of the station. Javier talked about the history of Isla del Caņo, a former burial ground for the pre-Columbian folks, who left lots of the round stone balls lying around. The island also, supposedly, was the inspiration for Robert Louis Stevenson's book, Treasure Island.

The other couple wanted to go hiking with Javier, and we preferred snorkeling, so Javier gave us the equipment and let us go off on our own in the natural rock harbor around the ranger station. The visibility was poor, which was one of the reasons we had landed and were supposed to go hiking first, and the current pushed us around a fair amount, but we saw some parrotfish and lots of small cleaner wrasse in the rough water around the rocks.

After probably half an hour of snorkeling, we got bored and headed back for the beach. We sat on a towel for a while, but the no see 'ems on the island were picking our legs apart, so we got up to go for a walk down the beach. The sand was pebbly and coarse, and got into our sandals.

Hari stopped for a while to chase fish in the tide pools with her new underwater camera housing, while Eric stood in deep water to try and protect his ankles from the insects.

The jungle extended all the way to the sand, and a steep climb was barely visible behind the first layer of trees. Patches of palms seemed to provide some form of access point to the inner jungle, but it would still be tough going. For the conquistadors who landed here, hacking through the rainforest must have been nightmarish work.

We walked down the beach until it turned rocky, then headed back to our gear to get bug repellent. We sat on a picnic bench near the ranger station and watched the golf-ball sized hermit crabs storm across the beach, up the hills into the jungle and over the tables. When one of the other groups on the island threw some bread on the ground, all the crabs started heading in one direction, coming out of the forest and the sand like ants and making a carpet of moving shells on the beach.

After a lunch prepared by Carlos, we loaded into the boat and headed out offshore until Javier found a good dive spot. The water was 30-40 feet deep but clear, and we could see stingrays half buried in the sand on the ocean floor. Almost immediately, some blue jacks swam by, and then Javier found a whitetip reef shark for us to follow.

He borrowed Hari's camera and dove way down to take some really good pictures of the sharks and stingrays, then found a green sea turtle and followed it for a while.

The bottom was occasionally rocky, but mostly sandy without very many fish and not much coral.

After following some more turtles for a while, we got back in the boat and headed to another location, closer to some rocks, where the water was shallower and there were more tropical fish, like Moorish Idols and tang. As we floated around the rocks, a huge school of silver horse eye jacks swam past, and we started diving down to swim in the middle of them to be engulfed in a wall of battleship gray fish.