Marine
Mammals
In the animal kingdom there are many different groups or "classes" such as reptiles, birds, amphibians and mammals. All mammals have five characteristics in common:
Dolphins are one of many marine mammals that inhabit the sea, others being manatees, otters, sea lions and whales.All the whales, dolphins and porpoises belong to the order called Cetacea, which can be further divided into three smaller groups known as suborders. The Archeocetes were the ancient whales and are now extinct. The second group, the Mysticetes, include, among others, the gigantic blue, grey and humpback whales. Members of this suborder have two blowholes and instead of teeth, have a series of comb-like plates called baleen which they use to strain plankton and shrimp from the water as a food source.
The largest suborder is the Odontocetes , also known as the toothed whales which includes groups such as the sperm whales, belugas and dolphins. The number of teeth may vary with the species, but all use their teeth for catching, not chewing, their food. There are ten different families of toothed whales.
Porpoise
Dolphin
The
Atlantic Bottlenose Dolphin
The Atlantic bottlenose dolphin can be found throughout the temperate, tropical and sub-tropical waters of the Atlantic Ocean. With a great deal of variety in size, appearance and behaviors, these dolphins are further divided into approximately nine different sub-species. For example, the bottlenose dolphins off the United Kingdom may weigh up to 1200 pounds and migrate short distances to locate food or evade predators. In the shallow Bahamian waters, Atlantic bottlenose dolphins grow up to nine feet in length weighing up to 500 pounds. Average lifespan for this species in the wild is approximately 25 years.
Bottlenose dolphins are found in temperate
waters (royal blue) throughout the world.
As mammals like us, dolphins are born with hair but where is the hair located? It was on top of the rostrum, the bony extension of their skull used to touch and move objects, but the few hairs usually fall out just before the calf is born or shortly thereafter. In general dolphins are well known for their bottlenose or rostrum with the built-in smile. The rostrum is a bony extension of their skull used to touch and move objects since they don't have hands.
Inside the dolphin's mouth, you will find 76 to 98 conically-shaped teeth used for defense or to grab their prey, which is then swallowed whole. As far as diet, these dolphins are known as "catholic" feeders, eating whatever fish species is locally available. Primarily they eat schooling fish - herring, mackerel, mullet or capelin to name a few - but also some crustaceans and molluscs, such as squid or shrimp.
Where do dolphins breathe from and create sounds? Not the mouth! The blowhole, located on top of the head, is used for both breathing and sound production. Dolphins generally take a breath about every 30 seconds but can remain submerged up to 8 minutes. The buzzes, chirps, clicks and whistles you will hear today all come from this area . Click here to listen to examples. Some sounds are actually forced through the dolphin's forehead, also known as the melon. This area of fat acts as acoustic lens, focusing the sounds dolphins create for echolocation into a concentrated beam.
Sight,
Smell & Hearing
Though this species of dolphin tends to be a little nearsighted above the water, they can see clearly above and below the water, just as you would see when wearing a mask as a snorkeler. Do your eyes sting when you go into sea water? Well dolphin's eyes don't! That's because they are covered by a protective mucous which keeps seawater, parasites or bacteria from irritating the eyes.
Dolphins do not have a sense of smell but do appear to have compensated with a highly developed sense of hearing. Above the water they are quite capable of hearing a wide range of frequencies. The pin hole opening located about two inches behind the eye is the external opening to the ear canal.
Echolocation is very helpful tool for dolphins in the wild. It is used for navigation, finding food, avoiding predators and communication with other dolphins. Scientists believe that dolphins may also be able to produce a strong enough burst of sound to temporarily debilitate their prey, giving them the extra edge when hunting.
Fins
Of the three types of fins found on a dolphin which contain bones? Only the pectoral fins! An x-ray of the pectoral fins would reveal five digits and the same number of bones found in a human arm. Scientists believe that the ancestors of dolphins once walked on land over 53.5 million years ago. The pecs are used for stopping or steering whereas the dorsal fin on the back is used for stability, much like a keel on a boat, and the flukes are use for speed. Both the dorsal fin and flukes are made of collagen, a fibrous connective tissue similar to the cartilage in your nose and ears. Using the powerful muscle of the peduncle, dolphins can propel themselves in the water up to 25 miles per hour!
Mother nursing her calf
Nursing & Reproduction
As mammals, dolphins are born live, with the mother turning quickly to snap the umbilical cord. The resulting navel can be seen in the center of the dolphin's belly. Below the belly button are two sensitive areas: the genital area and, for females, the mammary slits. How can you tell the difference between a male and female dolphin? The number of slits! Male dolphins have two slits in this area and females have four. The extra two are the openings to the mammary glands. Remember: as mammals dolphins nurse their young. However, nursing has been modified for life in the sea. Once the calf curls its tongue around the teat inside the slit, the mother squirts the calorie-rich milk into the calf's mouth.
Dolphins and whales are gregarious animals and usually travel in social groups called pods. Larger groups of pods are referred to as a school. In deep waters offshore, animals may travel in large groups, even up to hundreds of individuals, and commonly travel in shallow water in small groups less than a dozen. Adult males are also commonly found in shallow waters swimming alone or with another adult male to which it has bonded. These "pair bonds" appear to be long term relationships for males which may last the rest of their lives.
Generally, dolphin pods can be grouped into three types: adult males, juvenile males and the last group being mothers, females and calves. Organized as a matriarchal society, females usually do not allow males within their social group unless it is mating season and only then will it be the dominant males. This ensures that the females will mate with the most "successful" males of the group, providing the potential offspring with the greatest chance for survival.
Interactive
Programs: A New Approach to Dolphin Education
Dolphins by nature are curious creatures, commonly investigating people swimming in their environment - the ocean. Their amiability has stirred the fascination with which we view these animals. Beginning in the early 1980's, a few facilities around the world began to offer a new and different type of dolphin presentation commonly referred to as a "swim program."
Cetaceans
In The Wild: A Shared Future
For cetaceans and all marine life to thrive in the oceans we must make a conscious effort to protect our oceans directly and indirectly. Recycling and disposing of trash, toxins or pollutants properly is a beginning.
Driftnets and indiscriminate fishing techniques can only be prevented by international public pressure. Public support was the main reason the "dolphin safe" tuna label was so successful in decreasing unnecessary deaths from 100,000 to less than 3,000 each season. You can make a difference by having a voice.
