By: Nicholas Yoshioka, UHM MOP Student
Spinner Dolphin Marine Mammal of the Month:
Spinner Dolphin
C
Scientific Name: Stenella longirostris Hawaiian Name: Nai‘a Range: Tropical, subtropical, warm temperate oceans Diet: Fish and deep ocean species (ie. lLanternfish, shrimp, and squid) Size: 1.7 to 2.2 meters, 75 kilograms Habitat: Mainly offshore, nearshore in certain island chains ICUN Red List Status: Unknown
haracterized by their curious and fun-loving nature, dolphins have become a well-known figure across all of the world’s oceans. Hawai‘i is home to three main species of dolphins -the bottlenose (Tursiops truncatus), the spotted (Stenella frontalis) and the spinner dolphins. Spinner dolphins (Stenella longirostris) have been seen across every tropical ocean around the world, and with advances in technology and better surveying techniques, we are just now beginning to understand their true nature.
that they leap out of the water. Unlike all other dolphin species, spinner dolphins “rotate” or “spin” themselves when they jump. This “spinning” however, is more than just some performance. Scientists and psychologists believe the purpose of spinning out of the water is to remove attached fish/parasites and to communicate through signaling -- signals like “Let’s go” or “Watch out.” Another unique characteristic of spinner dolphins is that they are mostly nocturnal. During the night, spinner dolphins dive into ocean depths of 3,000 feet to hunt Spinner dolphins received their name from the way for their prey. The pod is divided into subgroups which then take turns diving for food, looking out for predators, and supervising the young as they are not yet ready to make the long dives. A pod of spinner dolphins can be as many as a few dozens to a couple thousand in size in which they are more efficient in finding prey. After the pod is well fed, they make their way into the coastal areas of islands to rest and recharge for the next night -- this is when most tourists spot the dolphins. Parents, having done all the work getting the food and feeding the young, tire out and fall into a resting state where they can still supervise their young and recharge their energy, while the Spinner dolphin (Stenella longirostris) off of Big Island. Spinner dolphin juveniles, on the other hand, get a chance to Photo by: Scott Gregory, Flickr. 14| Seawords
