Costa Rica's Spinner Dolphins of Osa's Blue Water Pelagic. By Shawn Larkin
A version on this artical appeared in The Tico Times, Central America´s largest English language newspaper, in 2008. Check out www.ticotimes.net.
Meet The Spinners
Far out at sea off Costa Rica´s Osa Peninsula the sunlight falls in shifting laser-like rays through crystalline blue waters. Through this vast borderless pelagic ecosystem swims huge pods of spinner dolphins. They live here, within sight of Corcovado National Park and Caño Island Biological Reserve, in unprotected waters. They gather in startling numbers in the same tiny piece of open ocean day after day, month after month, year after year. Dear reader, in case you didn’t know, there are no other dolphins like the spinner dolphins.
Very distinctive is the spinner’s trademark spin. All day long, and probably all night, these dolphins shoot completely out of the water spinning so fast that they become a blur. A spinner may spin eight times around before splashdown.
Spinning for them might be a kind of fitness training for their very active lifestyle. Spinning also might help remove pesky fish that stick to the sides of the smooth dolphins. There are not many other animals that spin and I think I know why. When I try spinning around eight times as fast as possible I fall down. Even each spinner dolphin can only do so many spins. That might be why only a small part of the pod is up and spinning at any one time. Even little baby spinners spin.
Spinner dolphins are human sized, unlike their more famous cousins. Bottlenose dolphins are much bigger than the spinners in every way. They have bigger brains and bigger bodies and bigger- well you get the idea. They are more famous due to their exploits as movie and TV stars and reluctant warriors. Scientists and business men have long been big on bottlenose because this tough dolphin readily survives in captivity, unlike the more delicate and elegant spinner.
Costa Rica’s incredible spinner dolphins come way more concentrated than other dolphins like the bottlenose. Spinners pack together like people at a rock concert. But they might cover an area the size of hundred stadium shows. Does that seem big to you? On the open ocean a stadium could look like a speck. Or not even be visible at all.
Thousands of spinner dolphins disappear from the view of observers in smaller boats at around 3 nautical miles, if the boat has a high enough tower you might see the white splash of a spinner reentering the water from around five nautical miles away. The commercial fishing fleet’s helicopters use this white splash to find the spinners from over ten nautical miles away. The birds that swoop and hunt over the spinners can sometimes be seen on special tuna fleet radar from at least 24 nautical miles away.
Like icebergs only the tip of the pod is visible from the surface, the vast bulk is only seen below. The spinners are packed because they are extremely social, constantly chattering and touching. They seem to spend as almost as much time mating and blowing bubbles on each other as they do surfacing to breath. They are the most gregarious of all of Costa Rica´s cetaceans- the dolphins and whales.
The spinners rarely split into smaller groups due to natural conditions, usually during rough seas. Sadly, here in the Osa the commercial tuna boats have been splitting up the groups, and killing dolphins, nearly daily.
But the spinners still keep getting back together in massive groups in the same places and spinning every day, weather and commercial tuna operations permitting. They have been found here off the Osa for many years in the same area offshore of Caño Island Biological Reserve and Corcovado National Park. They are consistently found in this unprotected area just off the continental slope of the Osa peninsula; from about five to twenty nautical miles off Caño Island.
They seem to stick to a little piece of the big blue; clear pelagic waters where the bottom drops quickly from around 500 meters deep to over 2000 meters deep. Here, special conditions create an upwelling of deep water marine life and that means year round fish feasts. Thousands of dolphins spinning around and around night and day get pretty hungry and this area gives them plenty to eat.
No matter what spinners are up to they must come to the surface every few moments to breathe and as well as bust off some spins once and awhile. Probably because of this they are always on the move. They even move when they are resting. I have never seen a live spinner stop moving for more than a few seconds. They might swim ten nautical miles in one day and a little less at night.
The spinner lifestyle is action. They must be in peak shape to swim miles to hunting waters and party areas. There are no fat spinners. Many people look at jumping dolphins and say that they are playing. This is like watching a professional dance group or sports team drill and saying that they are playing. Yes they are playing, but there is also something much more serious going on than the word play implies. You might call it training.
The spinners share their world with a host of other big strange creatures, most of whom the spinners swim circles around. They frequently make other beasts the butt of their silly sense of humor. They might sneak up on other less aware creatures, mimic their movements and or sounds with dramatic and sometimes unnecessary flare, and then all cackle and chatter with laughter and high fives, or I guess you could say high fins. Not that they have done this to me or anything.
One of the most impressive things I have seen any animal do is the spinner dolphin sunset dance. When the sun sinks very low into a clear sky on a calm sea, the spinner dolphins start to dance. You might have to see it to believe it.
As the sun falls into the sea the dolphins spread out a little and many dolphins start to jump at once with less spinning and more hang time. They seem to suspend themselves in the air and bask in the glory of the setting sun. Many more dolphins than normal leap at all at once and fly from the water in synchronized waves. Their reverence for the setting sun awes. Writing these words brings me a memory that gives gives me chicken skin, you know goosebumps.
The sunset dance of the Osa´s spinner dolphins is not to be missed. Most people around the world will have to settle for enjoying the Costa Rican stars performing their ritual on the big screen in the new Oceans movie due out next year. But those of us who live in and visit Costa Rica have the chance to see the show on the biggest screen ever-real life. Long may the spinners dance into the Osa´s sunsets.
Copyright 2009 Shawn Larkin
