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Bottlenose Dolphin

Tursiops truncatus

Bottlenose dolphins can swim nearly 18 miles per hour, although they usually swim 2-4 miles per hour. (NASA/Wikimedia Commons)
Bottlenose dolphins can swim nearly 18 miles per hour, although they usually swim 2-4 miles per hour. (NASA/Wikimedia Commons)

The bottlenose dolphin is a large, grayish aquatic mammal that visits the lower and middle Chesapeake Bay in summer.


  • Slender, streamlined body that is grayish in color
  • Slightly paler sides and belly
  • Short, beak-like snout
  • Lower jaw is slightly longer than upper jaw
  • Slender, streamlined body
  • Blowhole on top of the head
  • Can grow to 12 feet long and usually weighs 300-400 pounds


  • Found mostly in warm, salty open waters
  • Also visits the lower reaches of rivers and harbors
  • Travels in small schools, or “pods,” of 2-15 dolphins
  • Can feed in fresh waters for short periods


  • Visits the Chesapeake Bay in summer
  • Most often seen in the lower Chesapeake Bay near Cape Charles and the James and Elizabeth rivers
  • May venture as far north as Baltimore Harbor, the Chester River and Washington, D.C.


  • Feeds mostly on fish such as spot, croakers, menhaden andsilver perch
  • Also eats shrimp, squid, crabs and other invertebrates
  • Uses its teeth to grasp its prey, then swallows it whole


  • Sharks such as bull sharksare dolphins’ greatest predators
  • Humans threaten dolphins through pollution and recreational fishing gear


  • Uses sound to communicate with other dolphins, navigate through the water, watch for predators and find its prey
  • Sounds include clicking, creaking, squeaking and whistling
  • Each dolphin is believed to have its own unique whistle
  • Makes puffing and hissing sounds as it exhales through its blowhole

Reproduction and Life Cycle:

  • Mates throughout the year
  • Females give birth to one calf every 3-6 years
  • The gestation period lasts about 12 months
  • Calves are born in the water
  • During the birth, an assisting dolphin (which may be either male or female) remains close to the mother. This assisting dolphin is often the only other dolphin allowed near the newborn calf.
  • Calves begin nursing within several hours of birth. They feed on their mother’s milk for 18 months.
  • Females reach sexual maturity between 5-12 years old, while males mature at 10-12 years old
  • Usually lives about 20-25 years, but some may live longer than 40 years

Other Facts:

  • The most common dolphin found along the Atlantic coast
  • An extremely social, intelligent mammal
  • Spends about one-third of each day sleeping, usually just below the surface of calm waters
  • Comes up for air 1-2 times per minute, although some bottlenose dolphins have been known to stay underwater for more than four minutes
  • Can swim nearly 18 miles per hour, but it usually swims 2-4 miles per hour
  • Even though they look friendly, bottlenose dolphins can be aggressive. They have been known to attack sharks and porpoises.

Sources and Additional Information:


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