A description of the Bottlenose Dolphin in the Chesapeake Bay.
In the Chesapeake Bay, a sighting of a dolphin is an exciting event, especially in the upper bay. The Chesapeake is the nation’s largest estuary, a body of water where salt water mixes with fresh, and dolphins like the saltier regions of the bay. So the farther north you go, the less likely it will be to have a sighting. But it does happen.
The Atlantic Bottlenose Dolphin can be found in the bay during summer months. They swim in small schools called pods. They are a relatively small, toothed marine mammal of grayish color with a pale underside. They can grow to 12 feet long and weigh up to 400 pounds.
They feed on many species of fish and shellfish, of which the Chesapeake abounds. Eels, catfish, menhaden, crabs and shrimp are at the top of their menu. Dolphins use their teeth to grasp their prey rather than biting and chewing. Grasp and down the hatch whole is the name of the game.
Dolphins search for prey using a kind of sonar. They emit clicking sounds and listen for return signals to determine prey location. They also use sound and body language for communication with other dolphins. They can be heard making squeaks and whistles.
Atlantic Bottlenose Dolphins mate throughout the year. Gestation last about 12 months. During the birthing process, an assisting dolphin remains close to the mother and is often the only other dolphin allowed near the newborn calf. This assisting dolphin may be a male or a female. Like all mammals, the calf begins nursing within hours of its birth and begins eating fish after 3 months.
Both males and females have genital slits on the underside of their bodies. The female’s slit contains the vagina and anus. Two mammary slits containing one nipple each is located on either side of her genital slit. Males retract their genitals into their slits. The ability to contain their sexual organs in this manner allows for maximum hydrodynamics.
Females reach sexual maturity somewhere between the ages of 5 and 12 years, while males mature later, between 10 and 12 years. It is estimated that Bottlenose Dolphins live to be 20 to25 years old, with documented cases of individuals living as long as 40.
Males compete for access to females. Fighting and herding are strategies males use to prevent other males from mating with claimed females. Intercourse takes place belly to belly. Dolphins have been observed engaging in intercourse when females are not in their estrus cycles and cannot produce young, as well as when they can.
Dolphins are at the top of the food chain and as such, have few natural enemies. Sharks are known to occasionally kill dolphins, but a full grown dolphin can be a dangerous foe. In addition, dolphins usually travel in pods which offer maximum protection.
Sighting the Bottlenose on the Chesapeake is an event worth noting. Seeing them gambling in your boat’s bow wave is always worth a picture.
For more articles about the Chesapeake by this author, see: The Chesapeake , The Bufflehead , The Sea Nettle , The Barnacle , The Blue Crab , The Oyster , The Eagle , The Great Blue Heron , The Osprey
© 2010 Consumer Guide by David Sullivan