Studying Dolphins for a Day
In college, I majored in marine biology and psychology so I could study marine mammal behavior. My dream was to work with dolphins, but the field was filled with people like me so I found myself working with harbor seals instead. Today was one of those rare opportunities to actually do something I’ve always wanted to do. I spent the entire day studying the behavior of bottlenose dolphins in the wild and then assisted with the necropsy of a dead bottlenose dolphin that washed ashore overnight. It was an incredible experience.
The first part of the morning was spent on a boat cruising up and down the coastline searching for pods of bottlenose dolphins to observe. The weather was beautiful and it didn’t take long to find them. There was plenty of activity to observe near a shallow flat just south of Cape Henry Lighthouse. It’s difficult to accurately count how many were in the area because our vision was limited to the surface. If I had to give an estimate it would be in the area of about 30 animals and probably 6 of those were calves. I had the chance to observe a variety of different behaviors in the four hours I was on the water.
Something I found interesting was that I never saw an animal by itself, they were always in groups of two or more and their interactions appeared to be mainly milling and social behaviors. There weren’t any noticeable feeding behaviors and they stayed in the same area swimming around appearing to only be interacting with each other and occasionally the boat. I watched as several animals kept rolling on the surface and swimming back and forth over each other. They seemed curious and would swim beside the boat rolling over on one side as if to get a better look at what I was doing. Something else that I noticed was that the mothers always had their flipper underneath their calf’s belly as they surfaced and the calf always seemed to be on the mother’s left side no matter what direction they were heading. The last thing I observed was on the way back to the marina. Everyone knows how much they enjoy riding the wake of a boat. It was an awesome sight to count as many as nine at a time riding the wake of the boat. They would take turns as some rode at the bow and others rode the wake to either side. It was the perfect final observation to record.
The afternoon was set aside to perform a necropsy on a dead bottlenose dolphin that had washed ashore in the middle of the night. It wasn’t part of the original plans but an opportunity I couldn’t pass on. The carcass had already begun to decompose so the necropsy was mainly to determine the possible cause of death and collect any samples possible for research purposes. It was exciting because I actually got to assist the lead scientist with the entire procedure.
The specimen was a juvenile male that measured 6 feet in length. The only external evidence of the cause of death were net marks around his rostrum which are a pretty good sign that he had been caught in a fishing net and probably drowned. Otherwise, he appeared to have been a healthy animal. The internal examination didn’t show anything out of the ordinary but did provide evidence that he was healthy and feeding right up to his death. Examining his stomach contents backed up the theory that he was caught in a fishing net and drowned. His first stomach was filled with whole and partially digested fish. The presence of whole fish suggests that he had been feeding at the time of his death. The contents of the stomachs were collected for a scientist that’s studying feeding habits of the local population. Several teeth and tissue samples were also collected to help determine the age of the animal and presence of chemicals and pollutants. It was an unnecessary death but not a wasted one.
It was a long day, nine hours to be exact, but in the end it was too short. I have been out of the field an in the classroom for six years and this experience reminded me of how much I miss being out there. I do enjoy teaching, but it was great to be a real scientist again even if it was just for a day.
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