SPINNER DOLPHINS
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OVERVIEW
 Are probably the most frequently encountered cetacean in nearshore waters of the Pacific Islands
Region.
 Spinner dolphins received their common name because they are often seen leaping and spinning
out of the water. The species' name, longirostris, is Latin for “long beak,” referring to their slender
shaped beak or rostrum.
 Regarded as one of the most acrobatic of dolphins, spinner dolphins are well known for their habit
of leaping from the water and spinning up to seven times in the air before falling back into the water.
APPEARANCE
 Relatively small compared with other species of oceanic dolphins.
 Slender, with thin, recurved flippers, and dorsal fins that usually range from slightly curved to erect
and triangular.
 Adult females are 4.6 to 6.7 feet long
 Adult males are 5.2 to 6.8 feet long.
 They reach weights of at least 181 pounds.
HABITAT
 Are found throughout the world in tropical and warm-temperate waters.
 Four subspecies of spinner dolphins have been described worldwide:
 Stenella longirostris longirostris (also known as Gray’s spinner dolphin)—which includes
the Hawaiian spinner dolphin—in the tropical Atlantic, Indian, and western and central
Pacific Oceans.
 S. l. orientalis in the eastern tropical Pacific Ocean
 S. l. centroamericana near Central America
 S. l. rosiventris, the dwarf spinner dolphin, in southeast Asia to northern Australia
LIFESPAN AND REPRODUCTION
 Like all marine mammals, spinner dolphins are slow reproducers. They live for about 20 years, with
some individuals living for at least 25 years.
 Spinner dolphins may mate year-round, with multiple males mating with one female.
 Gestation is similar to other dolphin species and lasts approximately 11 months.
 Spinner dolphins calve year-round, generally about once every 3 years, and lactate often for 1 to 2
years.
 They reach sexual maturity at around 7 years of age.
SPINNER DOLPHINS
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THREATS
A. MARINE DEBRIS
 Marine debris is a growing concern within the marine environment, as it poses multiple threats
to the marine ecosystem. For instance, spinner dolphins may ingest (either directly or through
prey items) or become entangled in marine debris.
These interactions may cause:
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Drowning
Debilitation
Limited predator avoidance
Internal or external wounds
Skin lesions or sores
Blockage of the digestive tract, resulting in starvation that often leads to death
Reductions in quality of life and/or reproductive capacity
Impairment of feeding capacity
Introduction and/or concentration of damaging or toxic compounds to the animal
B. HUMAN-MADE NOISE
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Humans introduce sound intentionally and unintentionally into the marine environment. This
could be from commercial and recreational ocean activities, navigation, oil and gas exploration
and acquisition, research, and military activities.
C. DISEASE
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Spinner dolphins, like all marine mammals, can be susceptible to widespread disease.
Outbreaks in spinner dolphins are not commonly reported, but scientists have previously
detected serious diseases, such as toxoplasmosis and cetacean morbillivirus.
D. CONSERVATION AND MANAGEMENT
We are committed to protecting spinner dolphins through various conservation, regulatory, and
enforcement measures. Our work includes:
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Proposing enhanced protections of Hawaiian spinner dolphins through regulatory action under
the Marine Mammal Protection Act
Promoting sustainable and legal wildlife viewing practices among the tourism industry and
local communities
Developing research priorities to monitor spinner dolphin abundance, health, and threats (such
as human disturbance)
Managing programs that support the protection and conservation of spinner dolphins,
including Dolphin SMART, the Dolphin-Safe Program, and the Dolphin Energetics Program
Educating the public on minimizing spinner dolphin disturbance by providing outreach
programs and educational materials
SPINNER DOLPHINS
DUGONG