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We are often asked about porpoise and dolphins when we are out on the water during one of our marine safaris. First, we do not have porpoise in Hawaiian waters. Porpoise have very blunt rostrums, short, triangular dorsal fins and their teeth are spade shaped. In the above photos, the triangular-shaped, dark dorsal fin is a spinner dolphin, whose rostrum very long. They have a black eye-stripe, which flows to the pectoral fin. Spinners grow 6 or 7 feet and weigh up to 170 pounds, according to research. They usually rest during the day and feed in the evening hours. Spinner dolphins can occur in groupings of hundreds, or even in the thousands, and those fortunate enough to come across them will be delighted by their leaping out of the water on their axis, sometimes jumping up to 10 or more times.
In the other picture, the sickle shaped dorsal fin is that of the bottlenose dolphin. Their rostrum is much shorter than the spinner dolphin’s. They can reach a length of 10-14 feet, according to National Geographic, weigh over 1,000 pounds and have been observed leaping out of the water up to 16 feet high, landing on their backs. They can live up to 50 years. Bottlenose are usually seen in groups of 10 or less. In Maui County, we have 137 bottlenose, according to Dr. Robin Baird, who tells us this population have cut themselves off from those of the Big Island and O’ahu. Researchers tell us they can make up to 1,000 clicks per second, using echolocation, which both species of dolphins do. Bottlenose are diurnal feeders and are frequently seen traveling with humpback whales. Sometimes they are seen on top of a whale, apparently playing, but researchers are not sure. In a past posting, we have a link to a video you can enjoy, if you haven’t seen it already. Both species have conical shaped teeth.
So, there you have it! The differences between the two species are distinct, but both are beautiful and really fun to find on any excursion. As with any marine mammal, while in Hawaii it is illegal to approach to swim with, or interact for any reason. Just remember to give them their due space and they will give you amazing memories.
