Who are the observers? Dolphins or humans?

We had nearly finished our survey today when the dolphins raised another vivid question about what they think of us.In the distance, we recognized a pair of large, scarred dolphins named Grin and Twin Dip. Grin is unmistakable. It has a large triangular chunk missing from its dorsal fin, like a macabre grin in silhouette.Grin usually swims with Twin Dip.

Their large size, constant companionship and many scars suggest they are bulls. Grin and Twin Dip were busy following and flanking a mother dolphin named LA Stick and her calf Cactus. Since Cactus was born before 2004, LA Stick may be dating again.It was strange that Twin Dip kept circling our boat. Half a dozen times, it broke from its synchronous swims with Grin to slowly circle us at close range.

It would approach from one side of the boat and swim around our bow to the other side. It would circle around back and pause as if listening and feeling the vibration of the purring engine. It made regular forays under the boat as well. Considering we were in 4 feet of water, it was like scooting under the bed on your stomach.

The circling behavior was exceptional for several reasons. None of the other dolphins stopped what they were doing to circle us. Twin Dip swam at the same depth in the water, about 1 foot under the surface. This is unusual because dolphins usually move up and down the water column. It maintained the same distance from the boat, between 7 and 10 feet from us. I rarely feel threatened when studying bottlenose dolphins at sea (swimming with them is different but you can’t do that here; its illegal to swim with wild dolphins in US waters).

Not feeling threatened is understandable. Dolphins rarely give me cause (actually, quite the opposite). They can’t hurt me in the boat, even if they wanted to. The noise of the engine precludes our use of hydrophones. Because we can’t hear their vocal commentary, we study at a sort of philosophical distance. Studying dolphin behavior is like studying human behavior through a sound-proof window. You know they’re talking but you can’t hear what they say. They leave the window; you can only wait for them to come back into view.

They do things you never see. There is much to infer, but marine mammalogists who study behavior quickly learn to avoid over-interpretation. Yet, you develop knowledge of their patterns and emotions like mother or dad interpreting their little baby who doesn’t yet talk. Experience helps you fill in the blanks.As Twin Dip circled us today, I remembered other circling dolphins. Only a small fraction of dolphins behave this way.

They are typically large animals in the company of mother-calf pairs. Although it is possible that they are ‘protecting’ the mother-calf pairs or threatening us away from their ‘quarry,’ the behavior may serve a very different purpose. When a dolphin circles us, it is usually the first time it has been so close to our boat. Since the difference between casual and scientific observation is data, I consulted my database when I got home.

Sure enough, we have only one picture of Twin Dip – taken July 31, 2004 – swimming a considerable distance from us. We saw it this past April, again at a considerable distance. Today was the first time it came near us.The other dolphins with Twin Dip are familiar with us. Indeed, they literally brought their socializing to us. Perhaps this put Twin Dip into a quandary. To stay with its companions, it had to swim near our boat.

No one can say whether they gave Twin Dip the courage to explore us carefully. But its many passes were not rushed like a calf flinging itself nervously at our boat and rushing back to its mother. Its passes were slow, direct, purposeful and repeated.It appeared to be studying us. You’ve got to wonder.