Saturday, October 07, 2006

Dolphins and companionship

Remember Frank Sinatra's song "I Wish I Were in Love Again?" "The lovely loving and the hateful hates, the conversation with the flying plates, I wish I were in love again ..."No one claims dolphins fall in love. They certainly don't marry. Social to the core, however, each has its favorite companions.

The problem is how to think about dolphin relationships.Two dolphins in our fair waters named DD1 and N have a definite relationship of some sort. DD1 is female. We find her on most surveys. Often alone, she nonetheless knows when the dolphins are having a party and is usually there. N is male. When we find N, he's usually with her. If they were humans, we'd say they're good friends or a couple.

However, animal behaviorists avoid talking about animals in human terms when it is inaccurate (anthropomorphism), which gets harder as you know animals better.Scientists measure dolphin companionship mathematically with the Coefficient of Association. The higher the coefficient, the more often two dolphins are together. DD1 and N have a high CoA. Translated, they spend a lot of time together. I'm not sure what to call their relationship. The term 'associates' is so hygienic. And their companionship is always provocative.

Dolphin relationships are hard to define in general because their companionships are fluid. Dolphins are often in the vicinity of one another but do not appear, from the surface anyway, to interact. You need time to see if they join up later.If they do join and meander together for a time, what do we conclude? Very good people friends may or may not spend a lot of time together. Deep friendship is not predicated on time together. Plus, what is time to creatures who are awake their entire lives?

One pretty June afternoon, a dozen dolphins threaded through a boat parade. Boat parades are series of boats that bunch up at no wake zones like cars bunch up around a four-way stop. It's tough to track dolphins through boat parades. They go deep and avoid the danger. We too must negotiate the traffic.Little clusters of dolphins socialized as they wound around the boats. Calves leapt and jabbed. Moms relaxed side by side.

N was trying to mate DD1. He'd swim over her (literally), they'd submerge and reappear amid splashes and sudden veering turns. She'd speed ahead, him hot on her heels. Flashes of white in green waters meant a dolphin rolling and 'flashing its white belly' at the other, the delphinid version of "Hey, check me out." It wasn't clear she was avoiding him until she kicked him in the face, neatly accomplished with a flick of the flukes during a chase. He persisted. Finally, she clarified her opinion with a dramatic behavior called rostral ram-aerial avoid.

In this behavior, one dolphin leaps skyward to avoid the underwater lunge of the other dolphin, which continues into the air. DD1 shot over the water in an aerial U-turn. N shot out after her. Then a big boat rumbled by. They bolted to surf its waves.Given that DD1 had her calf a month later, her ambivalence was understandable. Unhappily, her light-colored calf didn't survive. Afterwards, DD1 swam heavily, barely clearing the surface to breathe.

N swam at her side. One misty August morning, they were hunting. Each swung by the boat (link to Just swinging by) before resuming their search. Foraging dolphins usually work alone in solo search for sustenance. But they suddenly joined up, splashing the surface with a tail whip, a sign of conflict. It didn't last long.

They returned to feeding, DD1 powering through the water after a meal worth rushing for.Remembering their spat in June, I laughed. They reminded me of a bickering old couple whose relationship is unassailable. But they also made me wonder: Exactly how well established is the relationship between food and sex?

Quick "Facts about Dolphins"