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Dolphins		Education > Species > Dolphins

The Atlantic Bottlenose Dolphin (Tursiops truncatus) The Atlantic Bottlenose Dolphin can reach a length of up to 12 feet and a weight of 1,430 pounds. On the contrary, most specimens of the Bottlenose Dolphin are smaller, averaging about 9 feet and weighing about 500 pounds. The Bottlenose Dolphin is an inshore species. More recently, a pelagic species has been discovered. The Bottlenose Dolphin are known to ride the surf and have been seen jumping clear of the water as high as 15-20 feet. Most Bottlenose Dolphins occur in groups of several hundred individuals that usually consist of smaller groups, with no more than a dozen animals in each. Populations of these mammals inhabit the coast and inshore waters as far north as New England to southern Florida and west through the Gulf of Mexico. There is also an offshore population that lives along the edge of the continental shelf as far north as New Jersey. The animals inhabit different areas during different events in their life cycle (mating, birthing..). The coastal habitat of Bottlenose Dolphins has become hazardous to their health due to chemical pollution. Human interaction with the Dolphins is also problematic. People occasionally feed the wild animals. This occasional feeding leads the Dolphins to become habituated to human interaction. Many of those Dolphins will later get into trouble with fishhooks and fish lines.	Common Dolphin (Delphinus delphis) The Common Dolphin ranges in size from six to eight feet long. It is known to inhabit waters in the western North Atlantic from Venezuela to Newfoundland. This species is thought to frequently remain offshore, as opposed to Bottlenose that more often will swim inshore. Common Dolphins can be found in herds ranging from 50 to nearly 2000 animals. They are very active in the waters. Many will frequently jump clear of the water and bow ride for long periods of time. They are known to have one of the most complex coloration patterns of all cetaceans. If observed up close, one can note the distinct crisscross or hourglass pattern along the sides of the animal.	Risso's Dolphin (Gray Grampus) (Grampus griseus) Risso's Dolphins (Gray Grampus) average about 10 feet long and 650 pounds. Surveys and reports have found this Dolphin to be the most common along the continental slope from south Cape Cod to Cape Hatteras. On the contrary, there have been some sightings in Newfoundland and the Gulf of Mexico. Risso's Dolphin may be found in herds of as little as 30 animals or as large as several hundred. In the waters, they are very acrobatic (breaching, cartwheeling, lobtailing and spyhopping). Primarily, they are squid eaters; hence, they have teeth only in their lower jaw (a characteristic common to squid eaters). If sighted, one might note the numerous scratches on the body of this species. These scratches may have resulted from encounters with other grampus or perhaps with the squid. It is also important to note its dark dorsal fin, which may be used to distinguish this marine mammal from others.

Atlantic Spotted Dolphin (Stenella plagiodon) The Atlantic Spotted Dolphin can reach a maximum length of 7.5 feet. The Spotted Dolphin closely resembles the Atlantic Bottlenose Dolphin; however, the latter tends to be more slender. As the name "Spotted Dolphin" suggests, the adult animal is dorsally marked with numerous grayish-white spots and ventrally with darker spots. The extent of its coloration changes with age. Younger animals completely lack spots. The species occurs in herds of up to several hundred individuals, with smaller groups that could include from ten to fifty animals. They are frequently seen jumping clear of the water, and riding the bow wave of moving vessels. Spotted Dolphins are usually found farther offshore than Bottlenose. This species of Dolphin is thought to inhabit a range of the western North Atlantic from Cape May, New Jersey to Panama.	Striped Dolphin (Stenella coeruleoalba) The Striped Dolphin ranges in size from six to eight feet long. Males and females become sexually mature at about 5 to 9 years of age. Those animals that are mating can be found in "mating schools," which consist of approximately 225 mammals. The other animals remain in "non-mating schools," which average about 750 dolphins. There are 3 mating seasons: January-February, May-June, and September-October. The Striped Dolphin is known for its two distinctive black stripes: one band of black beginning near the eye and extending down the side of the body to the area of the anus, and a second band of black extending from the eye to the pectoral flipper.	Atlantic White-Sided Dolphin (Lagenorhynchus acutus) The Atlantic White-sided Dolphin ranges from about 7 to 9 feet in length. This species is only found in the North Atlantic Ocean, where it ranges from Cape Cod to Greenland (some individual animals have been spotted in the Chesapeake Bay). Most sightings of this animal have occurred in waters with a temperature below 12 degrees Celsius. The Atlantic White-sided Dolphin can be seen individually or in schools of up to 500 animals. These animals may scatter or split from their school in order to feed more efficiently. They are most often observed offshore. This species can be identified by its distinct coloration. There is a narrow white patch on its side that runs down the length of its back and tail. This white patch ends abruptly with a defined yellow or tan patch. This yellow area runs up toward the dorsal ridge of the tail.

Harbor Porpoise (Phocoena phocoena) The Harbor Porpoise ranges in size from 4 to 6 feet long. Most specimens never reach 6 feet. Henceforth, it is known to be one of the smallest of the oceanic cetaceans. It is one of the most common inshore species seen from Cape Hatteras to Greenland. Young Harbor Porpoises are born from April through July, after a gestation period of 11 months. At birth, a calf is about 3 feet 4 inches in length. Most females bear a calf annually. Hundreds of Porpoises are entangled and drowned in gill nets that are set each year. As of today, the National Marine Fishery Service now has the Harbor Porpoise listed as a "threatened" species in U.S. waters. This species can be easily recognized by its small size, triangular dorsal fin, and flattened teeth. It is also known for making a soft puffing sound as it exhales, rather than spouting. They relatively swim in shallow waters and near the surface. They are usually observed in small groups, from singles to groups of 10 animals.

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