“Do dolphins ever take vacations?” my sister asked. I’d been telling her how amazing and difficult it is to track the comings and goings of dolphins around John’s Pass.
A huge number of dolphins use this area. They move through it – and social companions – with relentless change. If you see dolphins in the morning and afternoon, chances are they’re two different groups. And if you see a particular dolphin on two occasions, chances are they travel with different companions.
Dolphins are inveterate travelers. As far as we know, they and their kin are the only animals that are active 24-7; everybody else either sleeps all night or all day. They sleep in microbursts about 20-40 seconds, resting just half their brain at a time.
So, they change partners and locations like people in a life-long square dance. Some dolphins are relative regulars in our area. Mothers with babies are the most likely to hang around, which makes our local backwaters vital nursery grounds. Some individuals leave for a month and then return. Others visit once a year, big bruisers with lots of scars who are probably wandering bulls. Does that make them tourists?
Once you get pictures of most of the dolphins in a photo identification catalogue, you realize we’ll get dolphins that have never been here or haven’t been here for years. Marine mammalogists tell dolphins apart by the marks on their dorsal fins, the fin that sticks up out of the water when they surface to breathe. Many fins have unique marks because they get ragged over time like you’re your fingernails would if you didn’t trim them. By studying the photographs, we can distinguish dolphins who actually live around here versus those who only visit. We know for sure that at least one dolphin who “lives” in Sarasota is here on an extended visit, Mr. or Ms. 130.
So, when my sister asked if dolphins take vacations, I thought about human tourism. Florida is a premier destination. Tourists in St. Petersburg get the ultimate mind eraser, the sea. They refresh body and soul on sugar-sand beaches with cool ice creams. They soar with prehistoric pelicans, loop-de-loop with terns and hunt with osprey. They ponder the giant birds of Florida. They pray for the manatees. We all gawk at the dolphins.
The middle of April gave us plenty of chances to gawk at some brand-new dolphins who visited for about a month. We knew they were new by their spectacular behavior called kerplunking.
Kerplunking is stunning feeding behavior named for the sound it makes. The dolphin raises its tailstock (peduncle) over the water surface and whaps the water with its flukes, “Ker-plunk!” The gesture has that look of controlled power we see in great golfers. In response, water shoots up several feet in the air. Under the water, kerplunking could create a sound wave or sudden morass of bubbles that scare or stun the fish and make they easier to eat.
“Ker-plunk!” goes one dolphin. “Ker-plunk!” goes another. Coupled with underwater vocalizations, the dolphins work a small area. Then they all sprint into the middle of it and mill around like people converging on the barbeque when the burgers are ready.
Even more curious about these particular kerplunkers was their group coordination. Dolphins are unusual animals because they help one another. Few animals do that. At least through the middle of May, you could see kerplunks in the distance regaling quiet morning lagoons with fountains of water.
We know kerplunking is common among Sarasota dolphins but not among locals. Will our local dolphins pick up on this dramatic new technique? Vacations are a human concept but you really have to wonder.