Friday, June 09, 2006

Dolphins have unique sleeping technique

What’s it like to sleep in the ocean? Late afternoon one Florida-perfect day, three big dolphins roamed a small shallow area. Like people, dolphins have many moods. This trio swam leisurely.They slowly sank from view. They stayed underwater a long time. They surfaced with the same unhurried rhythm. They were sleepy.We recognized Fish Lips and Ouch immediately by their dorsal fins. Ouch is missing a huge round chunk of skin and a strip of pigment.

Ouch and Fish Lips are always together. Between their companionship, large size and many scars, we think they’re bulls. Today they swam with a smaller unmarked dolphin. Perhaps it was young. Like our own children, young dolphins have few scars compared to adults. The relaxed trio swam in unison. They surfaced and sank as one in the hypnotic rhythm of a Lava Lamp.

If we could’ve seen them underwater, they’d look drowsy. We spent many minutes watching them drift far from the ‘road’ between the red and green channel markers that most boats use. This, we thought, is a good place to rest.After a while, we drifted together into the road. It was time to continue our survey. In the no-wake zone, we didn’t go much faster than the dolphins.

But we gently motored ahead and eventually pulled away.We don’t often see resting dolphins. Part of the reason is that, as far as we know, dolphin sleep is unique. Dolphins nap throughout the 24-hour day. Most animals either sleep all night or all day. And their naps are bizarre. Half the brain sleeps. The other half remains awake. You and I can go to sleep because we breathe without thinking. Dolphins have to think to breathe, which makes sense.

You wouldn’t want an automatic breathing system if you live in the water but breathe air. We reached the deep John’s Pass that opens to the Gulf of Mexico. There are always lots of boats here. As we putzed among them, I wondered if the trio would join us. After several minutes, they entered the pass. Unhurried, they too threaded their way through the boats.

Funny place to sleep, I thought. Wouldn’t they stay out of boat traffic? We approached them slowly. Fish Lips gave commentary, lazily rearing over the surface to chuff several times. Chuffs are loud exhalations that sound like coughs. No one is quite sure what they mean because they occur in various circumstances. When a dolphin chuffs near us, we drop back in case it means they’re annoyed. Instead, they swam to us, as happens often (which makes the behavior mysterious). Together again, we languidly entered a narrow pass between two islands.

It was sunset. The world was colored in breathtaking pastels. Another natural story unfolded. Thousands of birds were assembling to roost on little sand islands for the night. Crows, intelligent tool-using birds, flew in from all points. Amassed, they swung into formation, swirled around and landed. They swooped back into the air, circling and landing again and again.

Each time, they stayed on the sand longer. Gulls grouped by the hundreds, and intimidated by the crows, cracked the night with raucous cries. Terns sped past in small tense groups. Transfixed, we stopped to watch. It was like being in a National Geographic TV special.

Ouch and friends slowly pulled away. Grateful for dreamy quietude after busy weeks of work, we watched for a mesmerizing hour. Finally time to go, we headed in the direction the trio had gone. Egotistically, I wondered if they’d hung around. About 200 yards away, there was the tired trio of very tired dolphins.

Quick "Facts about Dolphins"