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Bottlenose Dolphins Kelly Yagerhofer
Summary • Bottlenose Dolphins, or "Flipper", are the most common members of the family of oceanic dolphinsand are seen along the shores of the United States. There are two species known as the common bottlenose dolphin and the Indo-Pacific bottlenose dolphin. They inhabit warm and temperate seas worldwide. (wiki) Bottlenose dolphins live in pods and they basically eat forage fish. Some work together to gather fish schools or hunt on their own. They search for prey mainly using echolocation. They emit clicking sounds and listen for the echo to determine the location and shape of nearby items, including potential prey. (wiki) They use sound for communication also, such as: squeaks and whistles from the blowhole, leaping from water, and slapping their tails on the water's surface. Bottlenose dolphins are one of the most intelligent mammals on Earth. (wiki) They are in a lot of aquarium shows and are used to locate sea mines and adversary divers that will hunt them for food.
Anatomy teeth • Bottlenose dolphins are generally gray in color. An adult is from 8-12 feet long. Their upper and lower jaws form a rostrum, or snout. This gives the animal its name. The purposeful nose is located at the top of the head called the blowhole . The nasal septum is seen when the blowhole opens. These dolphins have around 18-28 pointed teeth on each side of their jaws. The flukes and dorsal fin are formed of dense connective tissue and do not contain bone or muscle. (wiki) To propel themselves they move the flukes up and down. The pectoral flippers (at the sides of the body) are for steering; they contain bones homologous to the forelimbs of land mammals. (wiki) • A bottlenose dolphin was found in Japan that had two extra pectoral fins at the tail that were about the size of a humans pair of hands! rostrum and blowhole
Physiology • Echolocation • Dolphins use echolocationto find food. They locate by sending out sounds and listening for the echo. A pulse of clicking sounds is emitted in a focused beam in front of the dolphin. (wiki) To hear the echo they have two small ear openings that are behind their eyes. Once the interest is approached the echo becomes louder and the dolphins decrease the power of their sounds. Echolocation details, such as signal strength, spectral qualities, and discrimination, are well-understood by researchers. (wiki) • Eyesight • Dolphins have very good eyesight. The eyes are found at the sides of their head and they have a reflecting membrane, or tapetumlucidum, which helps their vision in a dim light. Their horseshoe-shaped, double-slit pupil enables dolphins to have good vision both in air and underwater. (wiki) When they are underwater the eyeball's lens serves to focus light, while in the air the light serves to contract the pupil, which results in a sharpness from a smaller hole. • Smell • A bottlenose dolphins smell is deprived because its blowhole is closed while underwater. It only opens to breathe. It has no olfactory nerves or olfactory lobe in the brain. Although, Bottlenose dolphins can notice salty, sweet, and bitter tastes. • Communication • Bottlenose dolphins communicate through sounds and body language. They leap out of water, snap their jaws, butt heads, and also slap their tails on the water surface. These gestures help keep track of other dolphins and to alert them about danger or food. If they lack vocal cords, they produce sounds using six air sacs near their blow hole. (wiki) Each animal has their own trademark whistle. The tonal whistle sounds allow dolphins to be near each other and figure out how to hunt. The burst-pulsed sounds are used to avoid physical anger.
Taxonomy • Dolphins are part of the Phylum Chordata. Chordata is the most advanced animal phylum. (notes) Most chordates have backbones and also include classes like fish and reptiles. • Dolphins class is Mammalia, which is the most advanced vertebrate group. (notes) Mammals are endothermic, breathe air with lungs, give birth to live young and nurse them with milk, and grow hair at some time in life. (notes) Their order is Cetacea. Genus is Tursiops and species is truncatus. (acs)
Ecology and Reproduction • Distribution • Bottlenose dolphins live in tropical waters worldwide of surface temperatures from 10° to 32°C. In the Pacific ocean they are found from northern Japan to Australia and from California to Chile. In the Atlantic Ocean, bottlenose dolphins are found from Nova Scotia to Patagonia and from Norway to the tip of South Africa. (sea world) They are the most abundant dolphin species along the United States coast from Cape Cod through the Gulf of Mexico. (sea world) They are also found in the Black Seas and Mediterranean. • Habitat • Bottlenose dolphins live from coastal waters to open oceans, which gives them two forms: coastal and offshore. They can be specified by their skull and body. Coastal type is adapted to warm, shallow waters while offshore is adapted to cooler, deeper waters. • Interactions • Males live either alone or in groups of three. Females live in groups up to 15. They live in fission-fusion societies of varying group size, within which individuals change associations, often on a daily or hourly basis. (wiki) Pods can form groups of 100 plus, and can add up to 1,000.
Reproduction • Both genders have genital slits on the underside of their bodies and simply use them to reproduce. The ability to stow their reproductive organs (especially in males) allows for maximum hydrodynamics. (wiki) Males compete for females. Mating happens belly to belly. Births can occur at any time. They are born in shallow water. To speed up nursing the mother ejects milk from her mammary glands. The calf suckles for 18-20 months.
Importance and Relationship with Humans • Contact • Dolphins show curiosity towards humans in or by water. Sometimes they even rescue divers! For example, In November 2004, four lifeguards were approached by a shark and the dolphins herded the swimmers together, surrounding them for about forty minutes. This helped the shark stay away. • A lot of dolphins perform in many aquaria which often causes trouble. Animal welfare activists say the dolphins don't have enough room or receive enough care during these shows. • Therapies for handicapped children can include interactions with bottlenose dolphins. (wiki) • The military of the United States and Russia train bottlenose dolphins as military dolphins for wartime tasks, such as locating sea mines and detecting enemy divers. (wiki) • Culture • There are television shows that have Bottlenose dolphins in them such as : Flipper, Dolphin Cove, seaQuest DSV, Zeus and Roxanne, and more. They also appear in novels such as Startide Rising, The Dolphins of Pern, and in a video game series Ecco the Dolphin. (which I have played before!) • The Miami Dolphins mascot is the Bottlenose dolphin and it is also their logo. • Threats • Bottlenose dolphins are killed in dolphin drive hunts for their meat. They often travel with tuna and get caught in tuna nets which can kill them. • The man-made chemical perfluorooctanesulfonic acid (PFOS) may be compromising the immune system of bottlenose dolphins. (wiki) • Protection • Bottlenose dolphins are not endangered. (wiki) Although some are threatened from environmental changes, like water pollution and harassment.
Bibliography sourcesstart • [http://en.wikipedia.org/wiki/Bottlenose_dolphin#SmellBottlenose Dolphins], Wikipedia • [http://www.acsonline.org/factpack/btlnose.htm Bottlenose Dolphins], American Cetacean Society • [http://www.follybeach.com/dolphins.php Atlantic Bottlenose Dolphins], Folly Beach • Mr. McHugh's notes • [http://seapics.com/feature-subject/dolphin-and-porpoise/bottlenose-dolphin-pictures-006.html Open-mouth threat display], Sea Pics • [http://www.itsnature.org/sea/aquatic-mammals/bottlenose-dolphin/ Bottlenose Dolphin], It’s Nature • [http://www.seaworld.org/animal-info/info-books/bottlenose/habitat-&-distribution.htm Bottlenose Dolphins], Sea World Animals
External Links • http://en.wikipedia.org/wiki/Bottlenose_dolphin#Smell • http://www.acsonline.org/factpack/btlnose.htm • http://www.follybeach.com/dolphins.php • http://seapics.com/feature-subject/dolphin-and-porpoise/bottlenose-dolphin-pictures-006.html • http://www.itsnature.org/sea/aquatic-mammals/bottlenose-dolphin/ • http://www.seaworld.org/animal-info/info-books/bottlenose/habitat-&-distribution.htm