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.
Appearance:
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
Habitat:
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
Range:
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.
Feeding:
Feeds mostly on fish such asspot, croakers, menhaden andsilver perch
Also eats shrimp, squid, crabs and other invertebrates
Uses its teeth to grasp its prey, then swallows it whole
Predators:
Sharks such as bull sharksare dolphins’ greatest predators
Humans threaten dolphins through pollution and recreational fishing gear
Voice:
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.
