Thursday, September 28, 2006

Dolphin's behavior can be puzzling

How many times do you have to see something to believe its real? Scientists grapple with this daily. Therefore, we collect data, more reliable than memory.One data-deserving behavior is called "just swinging by." Dolphins swing by when they approach the boat, check us out and resume their activities. Dolphin behavior is complicated because they match moods with the sea.

Yet, their behavior can be roughly divided into distractible and non-distractible. Distractible dolphins approach the boat. We suspect they aren't doing anything in particular and seek amusement, which boats can sometimes be. They may continue to do what they were doing when we approached and just bring it over as if we're another group of dolphins.

They may change what they were doing to approach us and continue to switch from one behavior to another. This reinforces our impression that they weren't doing anything in particular when we arrived. Dolphins swim all the time. That doesn't mean they're always doing something specific. Most animals have a lot of down time; busy humans are the main animals who violate this natural law. Either way, distractible dolphins provide the exquisite experience of watching them at close range at their prerogative.

There's no privilege like it on earth.Non-distractible dolphins are preoccupied. They ignore or avoid the boat. They're particularly non-distractible when hunting, traveling great distances under the water in search of prey. They're largely non-distractible when having sex too. 'Just swinging by' is a little of both. As we headed toward the last bay on our route, we saw a water bottle on the water."There's a lot of garbage around here," I thought as I reached for the net, "but at least it's not a plastic bag."Turtles here live on jellyfish.

A plastic bag looks like a jellyfish to a turtle. Eating a plastic bag kills turtles slowly, horribly, of starvation. The offending bottle slid along the boat and flowed into the net. I flipped it into the hold. It just took a couple of minutes. For those minutes, I hadn't been watching for dolphins. Turning to the sea, I was surprised by a mother and calf 6 feet from the boat. They headed right for us, their rounded heads like gray animated basketballs at the surface.

It was X and Little X. Little X was glued to X's side the way they do when traveling somewhere specific. It rose when she rose. It submerged when she submerged. They were clearly en route. They surfaced next to us several times in short succession, peering into our eyes. Then they reappeared 50 yards away, continuing on their way. Considering all the available water, they didn't have to surface next to our boat. Data collected, we too continued on our way. I turned and saluted as we moved off.We spied another mother and calf, JJ and Rim, at the very end of our route.

They spent last summer here, wintered elsewhere and returned in April. We were having brunch at the Pub when they swam past with Grin and Twin Dip. Rim spends more and more time with dolphins besides JJ, not quite psychologically weaned from mom. Though I was scanning this time, JJ and Rim appeared out of nowhere. Dolphins are of course entirely capable of "appearing out of nowhere." They hold their breath for minutes, even tiny calves.

They surface wherever they like. They don't have to surface near a boat. Yet, they too swung by the boat.Four times, they surfaced nearby, drawing closer each time to peer at us frankly. Given their first surface, "I bet they go under that causeway and just swung by to say hi." Indeed, they next appeared under the distant causeway. They too had changed course to approach, make eye contact and continue on their way.

To legally experience marine mammals closer than the mandated 50-yard harassment-free zone, you need a federal permit. Inherent in the permit is the supposition that closer interaction between dolphins and boat is the dolphins' choice. We make every effort not to change the behavior we study. But, our very presence on the water changes things if for no other reason than the throbbing intrusion of our engine on the vital aquatic sound stage.

When the dolphins draw closer than our data collecting distance, it's their choice. In fact, all close observations are because the dolphins let us. If dolphins wish to evade boats, no boat captain, regardless of experience, can change that if they wish to avoid harassing the animals. We remain very aware that dolphins let us study them. So, if it's their call, what are dolphins doing when they swing by? Are they curious, acknowledging, or perhaps greeting?

Quick "Facts about Dolphins"