The Hawaiian Spinner Dolphin
Other than the breathtaking beaches, mountains, hospitable people, and amazing food, Hawaii is also known to be home to some majestic creatures, be it terrestrial or marine. One of the most famous water animals which tourists in Hawaii love to see and observe are dolphins—more specifically the Hawaiian Spinner Dolphin.
The spinner dolphin (aka the long-snouted dolphin) is well-known for its acrobatic stunts and its ability to spin as it leaps out of the water, which is where the name spinner comes from. Many are familiar with this species of dolphin because of ocean parks and animal shows, popular all around the glob.
The Hawaiian Spinner Dolphin
- Scientific name: Stenella longirostris
- Hawaiian Name: Nai’a
- Size: 1.7 to 2.2 meters, 75 kilograms; males slightly larger than females
- Teeth: 45 to 65 sharp-pointed teeth
- Food: Fish — small deep-ocean species like lantern fish, shrimp and squid
- Habitat: Mainly offshore, near shore in certain island chains
- Range: Tropical, subtropical and warm temperate world ocean
- Status: Population unknown, but common in most parts of its range; substantial declines have occurred in the eastern tropical Pacific
Today, scientists in Hawaii don’t track the exact number of spinner dolphins that live in the Hawaiian waters. The most recent estimate of the spinner dolphin population is 3,351 individuals. This number comes from a (2002) ship line-transect survey done within the U.S. Exclusive Economic Zone (EEZ) waters surrounding the Hawaiian Islands.
These dolphins have a streamlined body with a protruding but narrow snout and a triangular-shaped dorsal fin. When it comes to size, the spinner dolphin is one of the smallest species of dolphin measuring in at around 4 1/2 – 8 feet in length and weighing between 50 – 175 pounds when fully matured.
Just like most dolphins, Hawaiian spinners also have a skin tone that fades from dark to light gray starting around the dorsal fin area which is a dark gray that fades to a light gray around the sides of their body and to a lighter gray or white under-body or belly.
DIET AND FEEDING
The typical diet for the spinner dolphin includes a variety of fish, shrimp and squid. They stay in warm waters that are several thousand feet deep because this is where the majority of their food can be found.
They hunt food in groups, where in one group will swim around their prey herding them into a small dense ball while one or two other dolphins swim through the densely compacted group of fish and take turns consuming the scared and paralyzed fish. Studies have found that they prefer hunting at night when their prey moves towards the surface of the water.
Trivia: Did you know that dolphins need to surface up on the water to breath? They can only hold their breath for up to 5-10 minutes each dive.
SOCIAL STRUCTURE, BEHAVIOR, AND COMMUNICATION
Spinner dolphins are known to form loose bonds with one another and may be seen interacting with different groups at different times. They are also polygamous, which means they change mating partners every couple of weeks or so.
However, mother dolphins often form close bonds with their calves and may continue to feed and nurture their young for up to 2 years.
Hawaiian spinners communicate using a combination of clicks and whistles. Each and every dolphin owns a unique frequency—similar to the distinction of a human’s voice, that allows them to determine which one is speaking when in a large group.
BREEDING AND LIFE SPAN
The average gestation period for the spinner dolphin is estimated to be around 10 – 11 months. Female dolphins may bear a single offspring once every 2 – 4 years.
Female dolphins sexually mature at around 4 – 7 years of age, while males mature between 6 – 10 years of age and these dolphins have an estimated lifespan of 20 – 30 years.