SEA OF CORTEZ, Mexico » While snorkeling in the Sea of Cortez last week, instead of swimming hard to stay warm and cover ground, I stayed close to Craig, kept my ears above the water and scrutinized every blob, lump and mass beneath me.

I moved with such caution because I was afraid—afraid I'd miss something.

When I was here last winter, the water was too cold for snorkeling. I did it anyway, but when I hit the water, even in my wet suit, I suffered. The gulf is getting warm now, and some bays are like bath water.

Still, it's hard to make the leap from the deck because often you can't see the bottom. When our sailboat's depth finder went on the blink, Craig drove toward shore while I directed from the bow. “;Looks OK,”; I called out. “;Let's anchor here.”;

When we dropped the lead line, though, we decided to move back a bit. The boat was in 8 feet of water.

From the shoreline to about 6 feet down, the water is crystal clear. But as the prolific plankton turns the water a deep green, the bottom gradually disappears.

The best snorkeling, therefore, is in shallow water in golden brown seaweed forests. The bushy seaweed stands usually grow in winding corridors that resemble Mililani streets. Most passageways go through, but many end in cul-de-sacs that require U-turns.

Backtracking is a pleasure, though, because these streets are paved with gold. It's not the precious metal the Spaniards lusted after, but for marine animal enthusiasts, it's as good as chests of treasure.

One of my best sightings was an octopus, the biggest I've ever seen. When sitting upright, the heads and bodies of Hawaii's two octopus species are about the size of coffee mugs. This octopus was a teakettle.

The creature sat in the sand like Jabba the Hut, a roundish blob with bulging eyes alert at the center. I only spotted the creature because a telltale tentacle curled around the outside of its body.

I called to Craig, and we floated over the octopus, staring down. Because diving for a closer look would surely cause the animal to flee, we agreed to go simultaneously.

Down we went, and as our faces approached the creature, it bolted sideways, flashing brown, red and pearly colors while changing its skin texture from smooth to pebbly to prickly. The octopus didn't run and hide, though, because it was holding a prize. As the animal scooted, we saw the body of a moray eel trailing behind, and then glimpsed the eel's half-eaten head.

As we drifted back to the surface, the octopus settled its webbed arms over the eel like a frilly skirt and resumed eating.

I don't know how an octopus catches a moray eel, but the battle between these two predators would be a memorable sight.

Usually octopuses here eat clams and snails, a fact I know because on another excursion, I found an octopus' garden. This was a hole in white sand surrounded by, and lined with, countless pearly, empty shells. One tentacle poked up from the center of this lovely lair, and when we dived down to investigate, the octopus backed into its home and slammed the door shut with a shell.

With the water warm and 3,000 species of fish and invertebrates in abundance here in the Sea of Cortez, I'm swimming slow, looking sharp and listening hard.

My favorite sound so far is, “;Susan! Come look!”;