101 Spotted Dolphins: Gregarious and Playful Ocean Friends
Like the Dalmatians that ride fire engines, the pantropical spotted dolphins that frolic along Hawaiian coastlines are born without spots. The unusual markings develop as the dolphins get older. Evidence suggests that these marine mammals were once four-legged land creatures that evolved into the ocean through millions of years of natural selection. Delphinidae are members of the Odontocetes (toothed whale) group, with the English word "dolphin" derived from the Greek delphys, meaning womb or source of life. The importance of dolphins has been recorded in ancient writings and scientific journals, and reports even include metaphysical dolphin/human encounters.
Described fondly as the "clowns" of Hawaiian dolphins, schools of spotted dolphins splashing and leaping can be seen from afar. The spotted is a fast and vivacious swimmer often joining with spinner dolphins in shallow waters around Kauai. Off shore, spotteds swim in groups of a few dozen to over a thousand.
Tagging studies have shown that the foraging range is 200 to 300 miles, indicating that these dolphins cruise much of the Hawaiian archipelago. To distinguish the spotted dolphin from other species, look for a slender, elongated body, six to seven feet long including its narrow beak and white snout tip, with a dark gray "cape" from forehead to dorsal.
The juveniles' distinct three-tone pattern grows into a mottled pattern of white spots as they mature into their 250-pound heavily spotted adulthood. The pantropical spotted dolphin (Stenella attentuata) is found in the Atlantic, Pacific and Indian Oceans in tropical and subtropical waters.
The dolphins have been well studied and researched specifically in the eastern tropical Pacific due to their close relationship with the tuna purse seine fishing industry. Since tuna and dolphins share the same diet, commercial fishermen use dolphins as locators of tuna.
Studies have concluded that since 1971, more than eight million dolphins have been killed by net entrapment. The National Marine Fisheries Service initiated the Dolphin Safe determination program to educate consumers and to help the dolphin population recover. The U.S. commercial fishing industry has improved techniques and modified fishing nets to substantially decrease the death toll of dolphins, yet fishing practices in other countries continue to be a problem. Here in Hawaii the human impact of pollution and over-fishing are the main threats to the dolphins' need for peace and privacy. Fortunately, yellow fin tuna (ahi) don't swim below schools of dolphins in Hawaiian waters.
Spinners and spotteds appear to feed at night while tuna are active in the daytime. After their active night-feeding dolphins swim into calm, shallow waters to rest during the day. They look very playful and eager to put on a show or ride a bow wake, yet most of the group is "sleeping." During these resting periods, the dolphins never stop conscious thought. They must continually float up to the surface for air. It has been observed that when a dolphin shuts one eye, it allows one-half of its brain to rest. After a period of time, it switches to the other eye to allow the other half of the brain to rest. Echolocation, the dolphin's amazing ability to "see" by sound interpretation, enables these animals to learn about their surroundings as well as locate the distance and direction of underwater objects. Dolphins can determine the exact location of a vessel or a swimmer and are acutely aware of whether they are chased or surrounded.
If you are fortunate enough to encounter a school of spotted dolphins, you will be able to enjoy their playful spirit in the wild.
