Pan -Tropical Spotted Dolphin

Samantha Warner

Summary The Pan tropical Spotted Dolphins are

located around tropical and warm-temperature waters all over the world. This is one of the most abundant dolphins in the eastern tropical Pacific and ranks second in abundance in the deeper waters of the Gulf of Mexico. Their color and size varies based on the range it is from. The spots are the defining characteristics in adults, but the younger dolphins seem to get mixed up with the bottlenose dolphin because of their undeveloped spots.

AnatomyThe Pan tropical dolphin has a long thin beak. Their

upper and lower jaws are dark while they’re separated by thin white lips. The chin, throat and belly are also white but can vary with pale grey. The belly tends to have a limited amount of spots. They contain three distinct bands of color. The lightest color is at the bottom of the dolphin, followed by a thin grey strip in the middle of the flank, and a dark grey back. The concave dorsal fin is pretty similar in color. The tail matches the color of the middle band.

PhysiologyThe Spotted dolphin is a very fast swimmer

and bow-rider. They are also prone to acrobatic aerial displays or “tricks”. They have between 32 and 42 teeth in each row of the upper jaw and 30 to 40 in each row of the lower jaw. They breathe by blowing air out of their blow holes which are at the top of their bodies. They can hold their breathe for about 30 seconds, but some can hold their breathes for up to 30 minutes.

Taxonomy The Pan tropical dolphin is from the

Animalia Kingdom. Its Phylum is Chordata which means it is a verterbrate or is closely related and has a dorsal nerve cord. It is from the Mammalia class which means they are air-breathing animals. Its subclass is Eutheria and order is Cetacea. The suborder is Odontoceti and it is from the Delphinadae family. The Genus is Stenella and the Species is S. attenuata. The Binomial name is Stenella attenuata.

Ecology and ReproductionPan tropical Spotted Dolphins live mainly in

tropical or warm waters. They are found in the Atlantic, Pacific and Indian Oceans. These dolphins are very often seen around islands and are also found in the eastern tropical Pacific, western North Atlantic, Gulf of Mexico and around Hawaii. They are found in temperate waters and inhabit the continental shelf, however, they are found in the shallow waters over sand flats. The Pan tropical Spotted Dolphin is sometimes found swimming with Yellow fin Tuna and also swims in schools with other dolphins like the Spinner Dolphin.

ReproductionFemale Spotted Dolphins reach their sexual

maturity at the age of 9-11 years while males at 12-15 years. Gestation period is between 11 and 11.5 months, and the calving interval is about 3 years. They remain in their location for about 1-2 years and their pregnancy rate is estimated at 0.3. It is thought that the life span of a Pan tropical Spotted Dolphin is around 45 years.

Importance and Relationship with HumansThese dolphins associate with the Yellow fin Tuna which has

put the dolphins in serious danger. In the 1960s and 1970s, fishermen would catch thousands of dolphins and tuna at once using purse seine nets. All the dolphins would die. Over a period of time while this was happening, 75% of the eastern Pacific’s population and over half the world’s total was wiped out. Many major supermarkets now have found it economically expedient to use tuna suppliers whose fishermen catch tuna by a more safe or “dolphin friendly” way. Because of the conservation programs, the Spotted Dolphin is now at ‘lower risk/conservation dependent’, meaning there are conservation and management programs in place that show concern for these species and help them to not be listed as threatened or endangered.

Works Cited1)

http://www.cms.int/reports/small_cetaceans/data/S_attenuata/s_attenuata.htm

2) http://www.nmfs.noaa.gov/pr/species/mammals/cetaceans/spotteddolphin_pantropical.htm

3) http://www.nsrl.ttu.edu/tmot1/stenatte.htm4)

http://www.animalcorner.co.uk/marine/dolphins/dolphins_pantrop.html

5) http://www.dolphinkind.com/dolphin_facts.html