Dolphins

During lunch today, I went to the beach at about 50th Street. Two pods of dolphins went by, heading north to south. The first group had about ten members, and they were all dark grey. The second group had six dolphins and two of them were a lighter grey. Perhaps they were Confederates?

No pics, because my cellphone made it hard to distinguish between "here's a fin" and "here's a pixel which is marginally darker than the pixels around it."