Post Reply dolphin addict?then come here for facts :D
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Dolphin Anatomy and Physiology


Dolphins may look like fish, but they’re mammals that have adapted over the years to water. There are a number of differences caused by living in water instead of on land. For instance, dolphins and other cetaceans have no hair whatsoever, with the exception of a few follicles on their lower jaws and snouts.


Dolphin Senses

Probably the most peculiar difference between land mammals and dolphins is the way they vocalize. Most mammals have a larynx or a similar structure that allows them to vocalize using throat vibrations and exhaled air. Dolphins and other cetaceans are no different; but they’re specially adapted to make extremely high-pitched sounds used for echolocation as well as more human-pitched sounds used for ordinary communication with others in their pod.

In addition, dolphins have extremely sharp hearing, and much better vision than one might expect of an animal that uses echolocation as its primary means of sensing the world. Dolphins can see limited colors, and even have limited binocular vision like a primate. They do not possess much of a sense of smell, however.
Swimming

One of the most interesting differences between cetaceans and fish is in their swimming method. Fish swim by wiggling left and right, and if you watch crocodiles and snakes you’ll see the same motion. But because dolphins were descended from mammals with a quite different skeletal structure, they use up and down strokes to swim.
Today you can still see some of the remnants of terrestrial mammals in the dolphin’s skeletal structure. For instance, they have forelimbs, but they’re adapted into flippers with shortened arm bones and no fingers. Hind limbs can sometimes be found as vestigial skeletal remains, much like tails can still be found vestigially on some humans. Most cetaceans, including dolphins, still have a pelvis, which is entirely absent from fish.

Unlike other mammals, a dolphin’s hind quarters are much, much more developed than its front musculature; the flippers are only to steer, while the tail provides most of the force of motion. Dolphins have also developed horizontal flukes on their tail to make propulsion more efficient, and they’ve developed a dorsal fin just like fish. External parts that get in the way of a dolphin’s streamlined shape, like the genitalia or the ears, have been entirely lost, turning into internal organs instead.

Breathing

Dolphins, like other mammals, breathe air instead of water, and thus use lungs instead of gills. A dolphin that cannot surface also cannot breathe, and thus will drown; this is why dolphins caught in fishing nets are given such a poor chance of survival. Unlike most fish, dolphins are very much creatures of the surface of the ocean.

Like whales and other cetaceans, dolphins respire through a blowhole in the tops of their heads, breathing in air when they break the surface of the water. Unlike humans, dolphins do not breathe reflexively; instead, they have to remember to breathe. An unconscious dolphin is likely to be a dead dolphin. Though when actively swimming they must breathe fairly often, dolphins can hold their breath for fifteen minutes or more.



Dolphins and Language



Dolphins are like the kid that won’t shut up. They are almost constantly making sounds of one of two kinds: communicative or navigational. The different sounds are made in different ways.

Echolocation sounds are produced in their nasal passages just below their blowholes, and are called clicks. Clicks are sometimes produced in such rapid succession that they sound like buzzes or even quacks, and beamed forward from the dolphin’s head. These sounds are produced just behind the melon, an oily, slightly off-center lump on what you’d call the dolphin’s forehead, and the sound waves are focused forward through it.

Scientists are not entirely certain how the melon works, but it does seem to amplify and clarify the dolphin’s echolocation sounds, and may play a part in collecting the sounds bouncing back. They allow a dolphin to detect remarkably detailed information from the world around them. In one test, a dolphin found a marble-sized sphere at more than the length of a football field. Some scientists speculate that echolocation sounds may also be used to deliver an acoustic shock to small prey.
In the larynx, dolphins can produce high-pitched whistles and squeals which can rapidly change pitch. Whistles are single tones, with no vibrations that make them sound like buzzes. As far as scientists can tell, the whistles are a form of communication with other dolphins, and squeals are used to express alarm or sexual excitement. Dolphin Communication

There have been vast studies done on whether dolphins communicate with language, some more reliable than others. Even major researchers have made some pretty far-fetched claims with little scientific data supporting their claims. On the other end, fisheries and others who depend on the deaths of dolphins to support their livelihoods tend to downplay the communication and intelligence of dolphins, sometimes equating them with fish.

The truth, as in almost every case with extreme opposing claims, lies somewhere in the middle. Dolphins are highly intelligent, and have a greater brain-to-body-weight ratio (important in determining real intelligence) than any other mammal besides homo sapiens. They have brain ratios twice the size of any of the great apes, and are estimated to fall in approximately the same category as australopithecines, early humanoid ancestors. The appearance of the dolphin brain is also startlingly similar to that of a human brain.

Like most other animals, dolphins do have communication. Their squeals and whistles communicate emotional states and, often, the presence of danger and food in the area. They may also help them coordinate “herding” processes. Dolphin females often act as “midwives” to new mothers, and every dolphin in the pod cares for the others.

But do they communicate linguistically? There’s some evidence for it. Dolphins tend to stay within their own pods, and may have trouble understanding “foreign” dolphins. In studies done on dolphins near Scotland, individuals appear to have names; or at least, other dolphins use specific and unique whistles only in the presence of certain other dolphins, as if calling them by name. Unlike any other animal besides humans, dolphins exhibit a great tendency to take turns when vocalizing – making their communications sound like a conversation.

There have also been very basic linguistic studies of dolphin sound patterns. According to some studies, dolphin sounds follow the same basic patterns of all human-based language, from Morse code to Chinese. Though we cannot understand what they’re saying, it’s not beyond the bounds to state that dolphins may indeed have language, though it’s certainly a language unlike any we know today.


Dolphin Echolocation


Echolocation is a technique used by some animals to detect other animals, food and obstacles.

As implied by its name, this technique uses the echo, produced by a sound emitted by the animals with this capability, to locate such objects.

Dolphins and some whales, besides some other animals, like bats, have this ability.

The sound travels in the form of waves and when it is bounced back by solid objects either in water or air, it is then detected by the dolphin. This bouncing is called “echo” and it is the same as the voice echo we hear in caves, but at a much precise level.

Animals with echolocation ability, are capable to detect this echo when is deflected back by a solid object.

In the case of dolphins, they emit a a beam of clicking sounds forward in the direction fo their head and receive the echo from this sounds in the lower jaw.

This sophisticated system can calculate the distance where an object is located because of the time taken by the echo to return to the dolphin. As sounds can travel quite a distance in the water, dolphins are capable to detect dangers or food which is even out of sight.

This technique is used by humans in radars or sonars where some kind of wave is emitted and the bounced back wave is detected and processed.


Dolphin Senses


Imagine a world of darkness and sudden light, a world in which you can move not only side to side but up and down as well, a world without a bottom to it but instead a top to which you must periodically rise. And then imagine a world in which your hearing tells you as much about where you are and what’s around you as your eyes do, and often more.

This is the world a dolphin lives in. Though dolphins have all the same senses we do – sight, smell, taste, touch, and sound – they don’t work the same way. And they have an additional sense of echolocation. It’s also been postulated that they can orient themselves to magnetic fields.

Dolphin Sight

Dolphins have surprisingly good vision, able to see a fish in a trainer’s hand well enough to snatch it from the hand without harming the trainer. They have binocular vision to a certain degree, like a human does. They don’t have great color vision, though; it’s comparable to a severely color-blind person. And why would they need it when they live most of their lives well underwater?

Some dolphin behaviors associated with their vision indicate high specialization of the two sides of the brain, which is associated with intelligence. For instance, dolphins tend to swim in a counterclockwise direction in tanks. And when presented with new visual stimulation, like new people, they tend to look at them with their right eyes.

Dolphin Hearing and Echolocation

More important to a dolphin than sight, however, is dolphin hearing. Blindfolded dolphins have been found to have no trouble locating surprisingly small items in their tanks by using echolocation.

Whaling ships have long known how sensitive the hearing of any cetacean is. They always went as silent as they could when stalking whales; any sound in the water could lead to loss of their catch. Dolphins are no different from whales in this respect. Though their echolocation sounds don’t seem all that loud to a human, they can hear the bounced-back sounds from tiny objects as far off as 120 yards.

Dolphins may have two hearing sense organs. The melon of a dolphin (you can see this – it’s the big off-center lump on their foreheads) focuses their echolocation sounds, and may have just as much to do with collecting the sounds bounced back from echolocated objects. They do also have regular ears, and their ability to hear is among the best in the mammalian world.

Other Dolphin Senses

Dolphins are very sensory, and will seek out touch from other dolphins as well as from humans. They do not, however, have strong senses of smell or taste. Their primary sensory input comes from sound.

It’s possible that dolphins also can sense magnetic fields well enough to use the earth’s magnetism to navigate, although this is a poorly-researched area.


Dolphin Sounds and Accoustics


Most people have heard the chirping, squeaking noises made by dolphins which they use to communicate with dolphins and human trainers, and to navigate by using echolocation, or figuring out where things are by bouncing sound off them. Did you know dolphins can use their echolocation to detect three-inch objects further away than the length of a football field? Or that the possibility of true language exists, according to the theories of some researchers?

Do Dolphins Have Language?

Whether or not dolphins have language is a matter for debate unless and until we humans figure out how to speak to them. But evidence is mounting that dolphins may indeed have their own language.

Pods of dolphins in the English Channel stay on their own side – the French-water dolphins on the France side and the English-water dolphins on the England side – even though they are of exactly the same species and might be expected to mingle more. Some researchers say that this indicates not just language, but that two groups have developed distinct language that can’t be understood by the others.

Whether you buy that or not, there is a lot of research on dolphin vocabulary that indicates they communicate with at least as much sophistication as the higher apes. They have a vocabulary of danger sounds, food sounds, and seeking sounds, and sometimes put these sounds together in a reasonably complex fashion. There is also evidence that they may greet one another by name; specific sounds are only uttered when meeting certain dolphins. Dolphins and Man-Made Sonar

Because of millions of years of evolution, dolphin echolocation abilities are much superior to those of any man-made device. For this reason, the US Navy have been studying them for years in order to improve their own sonar. What they’ve found has been surprising.

Dolphins are incredibly good at distinguishing their own echolocation sonar even in very noisy underwater environments – and in fact are very good at locating the drift nets that entangle and kill so many of them, raising the question of why they are still often trapped in them. It has also been found, though, that some noisy locations confuse dolphins, perhaps explaining why dolphins often ground themselves in areas where Navy ships using active sonar are performing maneuvers. Could the clumsier man-made sonar be using frequencies the dolphins associate with something else? Or perhaps it’s like looking into a strobe light for them. Whatever the explanation, the Navy is interested in eradicating the problem.

Dolphin Beaching

It’s the most tragic thing a dolphin lover can see: a pod of dolphins that have apparently killed themselves by swimming onto a beach and lodging themselves there. Why do dolphins do this?

The most prominent theory currently is that something confuses their echolocation, “blinding” them to the location of the beach in relation to the open ocean. Since many beachings happen near man-made sonar activity, it’s possible that this impacts them. Some very recent autopsies of beached dolphin bodies show a very high percentage of damaged hearing, suggesting that a very powerful sound somewhere may have basically blown out their hearing. Dolphins see quite well, but without their ears they are disoriented and blinded. And when one dolphin beaches itself, the others are at risk because they will try to help him

However a beaching is initiated, it’s likely that it has much to do with how a dolphin perceives sound. Hopefully, we’ll soon understand enough about dolphin hearing to be able to prevent these tragedies.



i will post more later on
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a dolphin in captivity for 11 years was guided by humans to be trained and be a creature of the sea once again. at first, she was afrais. time took over and she got back into her element, the sea. she was released and is now living in her original home. free. this can be watched in animal planet; The Blue Beyond
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wildlife wrote:

a dolphin in captivity for 11 years was guided by humans to be trained and be a creature of the sea once again. at first, she was afrais. time took over and she got back into her element, the sea. she was released and is now living in her original home. free. this can be watched in animal planet; The Blue Beyond


cool i will get animal planet channel very soon i am so happy
Posted 3/20/09
wow i didn't know this about dolphins
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Date:2/4/09

Since i havent been on much i dicided to write about killar whales.This is gonna be about killer whales :Dand if u want to know more about killar whales feel free to ask.

Killer Whale Feeding


Just as we are at the top of the food chain on the planet, Orcas are at the top of the food chain in the ocean. Each Orca eats over 500 pounds of food each and every day. Depending on their geographical location, the Orcas diet consists of fish, squid, seals, sea lions, walruses, birds, sea turtles, otters, penguins, polar bears, reptiles, sharks, octopus, and smaller whales. There has even been an occasion where a moose was found in the stomach of an Orca.

While Orcas are known for their complex social structure, they have also been known to be cannibalistic. Researchers have not discovered in what instances one Orca might be compelled to eat another. It is a source of wonderment, since pods of Orcas operate just as close human families do - protecting their young, ill, and injured. However, occasions of Orcas eating members of their own pods are quite rare.

Orcas hunt with their pods, cooperating and communicating with each other to trap larger prey, and herding smaller prey into a confined area. If a confined area is not readily available, the Orca pod works together to create a confined area, by circling the grouped prey, while taking turns going into the center of the circle to feed. With the amount of food required for each Orca daily, it is no surprise that Orcas spend about 60% of their time foraging for food. While Orcas located in specific geographical regions tend to have specific diets, they readily change their preferences when what they usually eat is not immediately available.

Orcas choose, track, and stalk their prey, often choosing weaker targets for food, such as young sharks, or young blue whales. Orcas commonly use their tail flukes to kill or stun fish. Then, using their rather large teeth, they tear into their prey, or swallow it whole. Orcas do not chew their food, even if they tear into it. Once the food is in their mouths, they swallow it whole.

The stomach of an Orca is divided into three sections. The first section usually contains sand and broken shells. This is used to help the Orca crush its food up, since it was swallowed whole. The stomach remains in constant motion with the use of the muscle tissues. The rest of the digestion process occurs in the other two sections of the stomach, after the first section has properly crushed the food. Orcas drink sea water, and their kidneys cleanse the sea water by extracting the salt.

Orcas often share their food with younger Orcas, which is believed to occur when the older Orcas are trying to instill acceptable social behavior in the younger Orcas - much like we teach our young proper table manners, teach them to say 'Please' and 'Thank You,' and teach them to offer their guests refreshments. Researchers believe this because there have been countless instances of grown Orcas sharing food with younger Orcas who were perfectly capable of getting food for themselves.


Killer Whale the Largest Dolphin


Orcas, also known as Killer Whales, rule the sea. They are only endangered by human beings, as no other sea creature could possibly be a threat to them. Orca's are predators that will even attack other types of whales. Even with the danger that they represent, to both humans and other sea life, they are still considered to be one of the most majestic creatures in the ocean, and millions of people travel a long way every year, in hopes of getting a glimpse of them - from a safe distance.

Even though they are called whales, they actually belong to the dolphin family. Since Orcas are between 27 and 33 feet long, and weigh between 8,000 and 12,000 pounds when they are fully grown, with the males being larger than the females, they are indeed the largest dolphins in existence. The males can live as long as 60 years, while the females can live to be as old as 90.

Orcas are black, with patches of white on their skin. Their heads are round, and they have very distinctive beaks. Orcas have a large sickle shaped dorsal fin, and large flippers that are typical of all dolphins.

The dorsal fin is located on the top of the Orcas back, and the males dorsal fin can be up to six feet tall, while the females is only about four feet tall. Orcas can travel at speeds of 30 miles per hour. Orcas live in pods. The pods are small, and operate just as close families do. These pods are made up of 6 to 40 Orcas, and pods stay together throughout their entire lives. Members of the pods work together to protect the young, as well as the sick and injured members.

Orcas breed from winter to early spring near the surface of warm waters. The gestation period is from 16 - 17 months. The babies, called calves, are born between October and March. The calves are able to swim within thirty minutes of being born, and weigh up to 400 pounds. They are typically 6 to 8 feet long at birth. In most cases, each female only gives birth to one calf. Twins are rare. The calf usually stays with it's mother for a year, and sometimes longer.

The members of the pods hunt together, and work together to catch their prey. They survive on a diet of fish, squid, sharks, whales, seals, turtles, octopus, penguins, and sea gulls. Their teeth are typically about 3 inches long, and 1 inch in diameter. An average Orca eats an estimated 550 pounds of food each day or more. While Orcas do not migrate, they may travel hundreds of miles in order to catch seasonal prey.

Orcas have one blow hole, and they breathe air in above the surface of the water through their blow hole, which is located on top of their heads, above their eyes. Orcas are very vocal. They make a variety of sounds that sound much like clicks, whistles, and even screams. These sounds are used to communicate with each other when hunting prey, and for mating purposes. Each individual pod even has it's own accent, which makes it possible for members to recognize each other.

Orcas can be found in tropical waters, as well as arctic waters. Pods can be found in coastal waters, as well as deep waters. Orcas have been found in every ocean in the world, so they are not habitats of any particular climate or area - other than salt water.


Killer Whales Top Facts


Killer whales (Orcas) are fascinating creatures that attract a great deal of attention from marine biologists, as well as the general public. Constant research is always being done on killer whales, and new facts about their habits, socialization, intelligence, and travel patterns are discovered every year. Here are some facts that you may not know.

•killer whales are one of the fastest creatures in the sea, traveling up to 30 miles per hour.

•killer whales are able to control the flow of blood to their hearts and brains, which keeps them from suffering from a lack of oxygen when they are deep underwater.

•killer whales eat up to 5% of their body weight each day. This averages out to over 500 pounds of food for each Orca.

•While killer whales do most of their socialization within their own pods, pods do socialize with other pods as well.

•When breeding, killer whales do not breed with relatives. They only breed with killer whales that are not closely related to them within their own pods.

•killer whales are called "Killer Whales" because they feed on other dolphins and smaller whales, not because they kill people. They are also know as orcas.

•The only recorded instances of a killer whale attacking a human being have been of attacks by Orcas held in captivity. No killer whale that lives in the wilds has ever attacked a human being.

•Every killer whale has a mark behind it's dorsal fin that is totally unique. These marks are used by humans to distinguish one killer whale from another, just as humans each have their own specific characteristics that make our appearances different from every one else's.

•All killer whales use vocalization to communicate with each other, but each pod has it's own unique 'accent,' which makes it easy for Orcas to identify members of their own pods.

•Pods of killer whales are found in all oceans in the world, but the greatest numbers are found in cooler waters.

•killer whales are actually dolphins. In fact, they are the largest dolphins in existence, and can be up to 30 feet or more in length, and weigh up to 12,000 pounds.

killer whale picture•A killer whale brain is five times larger than a humans. They are very social, intelligent, and curious. killer whales brains that have been studied with microscopes have proven to be as structured and developed as the human brain.

•killer whales have very organized and complex social structures, and divide themselves in pods, which operate as human families do. They protect their young, ill, and injured within their pods.

•killer whales spend 60% of their time foraging for food. killer whales do not migrate, but they have been known to travel hundreds of miles to find fresh food that is in 'season.'

•The life expectancy of an killer whale in the wild is 50 - 60 years for males, and up to 90 years for females, however, no killer whale that was held in captivity has lived longer than 30 years, and the average life expectancy for captive Orcas is only 20 years.

•Female killer whales usually do not breed until they are between the ages of 12 and 16 years old. Their gestation period is 15 - 17 months, as opposed to 9 months for humans. They nurse their calves for up to 2 years. On an average, each female Orca that lives in the wilds will have approximately five calves during her lifetime.


hope u enjoy that i'll add more next week (if i can...)
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oh yh little hint next is gonna be about different species i read it through its quite intresting
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ya it is so interesting
i really enjoy reading it
to know more information about animals is really so interesting for me
thank you
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sorry for late post wasnt able to go online!also i wont be doing dolphin species coz its got to much info so i'll put them in different posts sorry!so this week it will be about Pink Dolphins :D

Date: 13/04/09

Pink Dolphins


While you expect to see dolphins in the ocean, very few people realize that they can be found in fresh water rivers as well.

There are five species of dolphins that make their homes in rivers, being the most popular of them the Pink Dolphins also known as Boto, Boutu or Amazon River dolphins as it inhabits the Amazon River.

The scientific name of pink dolphins from the Amazon are Inia Geoffrensis and they belong to the genus Inea, part of the family Platanistoidea, which is conformed by the five species of river dolphins.

Pink dolphins are not the same dolphins that you would see in the ocean; they have special adaptations to their habitat. In fact, river dolphins are only distantly related to sea dolphins.

They belong taxonomically speaking to different families. The oceanic dolphins belong to the family delphinidae while river dolphins belong to the family Platanistoidea as we said above.

Among the five species of river dolphins, Amazon pink dolphins are considered the most intelligent of them, with a brain capacity 40% larger than that of humans.

Pink dolphins inhabit the Amazon River, but they can also be found in the Orinoco basins and the upper Madeira River as well. While they are mostly pink, these dolphins have various colored skins, which can be light gray, pink, or brown.

The Amazon River pink dolphins conform the largest population of river dolphins in existence as the other four species are extinct or close to extinction.

The river dolphins are among the most endangered species of all the world's cetaceans. Pink dolphins have been listed by the International Union for the Conservation of Nature (IUCN) as a “vulnerable species-threatened” and recently was moved to “endangered species-threatened”

These friendly and social creatures have been living for centuries in the Amazon and its tributaries, but the accelerated destruction of the Amazon basin have put them in a every time more dangerous situation.

The raise in contaminant levels of mercury have caused and increased number of deaths among pink dolphins, especially near gold mines where mercury is used as part of the gold mining process.

Tthe increase of traffic also threatens these creatures as they are curious by nature and they sometime approach to vessels where they are easily hurt by the sharp propellers.

Additionally, the noise produced by engines and motors and the sound pollution caused by them, has been considered to produce a disorienting phenomenon in their navigations systems, causing the death of many pink dolphins.


Social Habits of Pink Dolphins


Pink dolphins have no natural predators in the Amazon River other than humans, therefore they are usually found alone or in couples hunting, as they do not need to form pods for protection as the ocean dolphins do.

While they are looking for food in the floodplains, they are often found alone.

This behavior does not mean that this kind of dolphins do not socialize, they also form pods of 5 to 8 members and they cooperate for herding fish, especially at river confluences when this hunting technique needs to be applied for increase efficiency.


What do Pink Dolphins Eat?


Pink dolphins eat crabs, catfish, small river fish and even small turtles.

As crabs and turtles have to be catch mainly at the bottom of the river, pink dolphins spend a lot of time while swimming looking at the bottom of the river for food.

The boto cervical vertebrae are not fused allowing them to move their head up to 180 degrees, which is a great help for hunting in shallow waters and floodplains.

Hunting fish require some techniques like herding, where they round a fish pod to concentrate fish and take turns for feeding. This procedure is largely used by their oceanic cousins.


Physical Description of Pink Dolphins


Pink dolphins can be found in pink, light gray or brown colors but there is not conclusive evidence of the reason why pink dolphins are pink.

It could be an adaptation to the river life or caused by the presence of capillaries near the surface of the skin what provide them such impressive color.

Additionally, pink dolphins get pinker when they are excited or surprised, resembling blushing in humans.

The Amazon River dolphin is between six and eight feet long, and weighs between 185 and 355 pounds when it is fully grown.

River dolphins are typically smaller than sea dolphins but they have longer snouts, an adaptation provided by evolution, which is needed to hunt at the bottom of the river. River dolphins also tend to have more pointy teeth than sea dolphins.

Pink dolphins have humpbacks instead of dorsal fins.


Behavior of Pink Dolphins


Pink dolphins appear to be the friendliest of all the river dolphins when approaching to humans and some stories of people being pushed to the shores by them are common among some tribes in the Amazon.

They swim up to 30 kilometers in one day, although they usually swim slowly looking for food at the bottom of the river.


How do Pink Dolphins Reproduce?


Females and males mate to start a gestation period which is believed to last from nine to twelve months. Copulation is performed between males and females belly to belly.

Calves are born about 75 cm long and weighing a bit more than 1 Kg.

Pink dolphins deliver their babies when the Amazon River is at its high between the months of May and July.

Most species of river dolphins are almost blind, due to navigating muddy waters, but their brains are extremely large and well developed, however pink dolphins are considered to have a relatively good sight.

Unlike sea dolphins, river dolphins have what resembles fingers on the ends of their flippers, and their dorsal fins are much smaller than that of sea dolphins or even have humpbacks instead of dorsal fins like the pink river dolphin.


well i guess thats the end!next weeks dolphin specie wil be...
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Dolphin Anatomy and Physiology


Dolphins may look like fish, but they’re mammals that have adapted over the years to water. There are a number of differences caused by living in water instead of on land. For instance, dolphins and other cetaceans have no hair whatsoever, with the exception of a few follicles on their lower jaws and snouts.


Dolphin Senses

Probably the most peculiar difference between land mammals and dolphins is the way they vocalize. Most mammals have a larynx or a similar structure that allows them to vocalize using throat vibrations and exhaled air. Dolphins and other cetaceans are no different; but they’re specially adapted to make extremely high-pitched sounds used for echolocation as well as more human-pitched sounds used for ordinary communication with others in their pod.

In addition, dolphins have extremely sharp hearing, and much better vision than one might expect of an animal that uses echolocation as its primary means of sensing the world. Dolphins can see limited colors, and even have limited binocular vision like a primate. They do not possess much of a sense of smell, however.
Swimming

One of the most interesting differences between cetaceans and fish is in their swimming method. Fish swim by wiggling left and right, and if you watch crocodiles and snakes you’ll see the same motion. But because dolphins were descended from mammals with a quite different skeletal structure, they use up and down strokes to swim.
Today you can still see some of the remnants of terrestrial mammals in the dolphin’s skeletal structure. For instance, they have forelimbs, but they’re adapted into flippers with shortened arm bones and no fingers. Hind limbs can sometimes be found as vestigial skeletal remains, much like tails can still be found vestigially on some humans. Most cetaceans, including dolphins, still have a pelvis, which is entirely absent from fish.

Unlike other mammals, a dolphin’s hind quarters are much, much more developed than its front musculature; the flippers are only to steer, while the tail provides most of the force of motion. Dolphins have also developed horizontal flukes on their tail to make propulsion more efficient, and they’ve developed a dorsal fin just like fish. External parts that get in the way of a dolphin’s streamlined shape, like the genitalia or the ears, have been entirely lost, turning into internal organs instead.

Breathing

Dolphins, like other mammals, breathe air instead of water, and thus use lungs instead of gills. A dolphin that cannot surface also cannot breathe, and thus will drown; this is why dolphins caught in fishing nets are given such a poor chance of survival. Unlike most fish, dolphins are very much creatures of the surface of the ocean.

Like whales and other cetaceans, dolphins respire through a blowhole in the tops of their heads, breathing in air when they break the surface of the water. Unlike humans, dolphins do not breathe reflexively; instead, they have to remember to breathe. An unconscious dolphin is likely to be a dead dolphin. Though when actively swimming they must breathe fairly often, dolphins can hold their breath for fifteen minutes or more.



Dolphins and Language



Dolphins are like the kid that won’t shut up. They are almost constantly making sounds of one of two kinds: communicative or navigational. The different sounds are made in different ways.

Echolocation sounds are produced in their nasal passages just below their blowholes, and are called clicks. Clicks are sometimes produced in such rapid succession that they sound like buzzes or even quacks, and beamed forward from the dolphin’s head. These sounds are produced just behind the melon, an oily, slightly off-center lump on what you’d call the dolphin’s forehead, and the sound waves are focused forward through it.

Scientists are not entirely certain how the melon works, but it does seem to amplify and clarify the dolphin’s echolocation sounds, and may play a part in collecting the sounds bouncing back. They allow a dolphin to detect remarkably detailed information from the world around them. In one test, a dolphin found a marble-sized sphere at more than the length of a football field. Some scientists speculate that echolocation sounds may also be used to deliver an acoustic shock to small prey.
In the larynx, dolphins can produce high-pitched whistles and squeals which can rapidly change pitch. Whistles are single tones, with no vibrations that make them sound like buzzes. As far as scientists can tell, the whistles are a form of communication with other dolphins, and squeals are used to express alarm or sexual excitement. Dolphin Communication

There have been vast studies done on whether dolphins communicate with language, some more reliable than others. Even major researchers have made some pretty far-fetched claims with little scientific data supporting their claims. On the other end, fisheries and others who depend on the deaths of dolphins to support their livelihoods tend to downplay the communication and intelligence of dolphins, sometimes equating them with fish.

The truth, as in almost every case with extreme opposing claims, lies somewhere in the middle. Dolphins are highly intelligent, and have a greater brain-to-body-weight ratio (important in determining real intelligence) than any other mammal besides homo sapiens. They have brain ratios twice the size of any of the great apes, and are estimated to fall in approximately the same category as australopithecines, early humanoid ancestors. The appearance of the dolphin brain is also startlingly similar to that of a human brain.

Like most other animals, dolphins do have communication. Their squeals and whistles communicate emotional states and, often, the presence of danger and food in the area. They may also help them coordinate “herding” processes. Dolphin females often act as “midwives” to new mothers, and every dolphin in the pod cares for the others.

But do they communicate linguistically? There’s some evidence for it. Dolphins tend to stay within their own pods, and may have trouble understanding “foreign” dolphins. In studies done on dolphins near Scotland, individuals appear to have names; or at least, other dolphins use specific and unique whistles only in the presence of certain other dolphins, as if calling them by name. Unlike any other animal besides humans, dolphins exhibit a great tendency to take turns when vocalizing – making their communications sound like a conversation.

There have also been very basic linguistic studies of dolphin sound patterns. According to some studies, dolphin sounds follow the same basic patterns of all human-based language, from Morse code to Chinese. Though we cannot understand what they’re saying, it’s not beyond the bounds to state that dolphins may indeed have language, though it’s certainly a language unlike any we know today.


Dolphin Echolocation


Echolocation is a technique used by some animals to detect other animals, food and obstacles.

As implied by its name, this technique uses the echo, produced by a sound emitted by the animals with this capability, to locate such objects.

Dolphins and some whales, besides some other animals, like bats, have this ability.

The sound travels in the form of waves and when it is bounced back by solid objects either in water or air, it is then detected by the dolphin. This bouncing is called “echo” and it is the same as the voice echo we hear in caves, but at a much precise level.

Animals with echolocation ability, are capable to detect this echo when is deflected back by a solid object.

In the case of dolphins, they emit a a beam of clicking sounds forward in the direction fo their head and receive the echo from this sounds in the lower jaw.

This sophisticated system can calculate the distance where an object is located because of the time taken by the echo to return to the dolphin. As sounds can travel quite a distance in the water, dolphins are capable to detect dangers or food which is even out of sight.

This technique is used by humans in radars or sonars where some kind of wave is emitted and the bounced back wave is detected and processed.


Dolphin Senses


Imagine a world of darkness and sudden light, a world in which you can move not only side to side but up and down as well, a world without a bottom to it but instead a top to which you must periodically rise. And then imagine a world in which your hearing tells you as much about where you are and what’s around you as your eyes do, and often more.

This is the world a dolphin lives in. Though dolphins have all the same senses we do – sight, smell, taste, touch, and sound – they don’t work the same way. And they have an additional sense of echolocation. It’s also been postulated that they can orient themselves to magnetic fields.

Dolphin Sight

Dolphins have surprisingly good vision, able to see a fish in a trainer’s hand well enough to snatch it from the hand without harming the trainer. They have binocular vision to a certain degree, like a human does. They don’t have great color vision, though; it’s comparable to a severely color-blind person. And why would they need it when they live most of their lives well underwater?

Some dolphin behaviors associated with their vision indicate high specialization of the two sides of the brain, which is associated with intelligence. For instance, dolphins tend to swim in a counterclockwise direction in tanks. And when presented with new visual stimulation, like new people, they tend to look at them with their right eyes.

Dolphin Hearing and Echolocation

More important to a dolphin than sight, however, is dolphin hearing. Blindfolded dolphins have been found to have no trouble locating surprisingly small items in their tanks by using echolocation.

Whaling ships have long known how sensitive the hearing of any cetacean is. They always went as silent as they could when stalking whales; any sound in the water could lead to loss of their catch. Dolphins are no different from whales in this respect. Though their echolocation sounds don’t seem all that loud to a human, they can hear the bounced-back sounds from tiny objects as far off as 120 yards.

Dolphins may have two hearing sense organs. The melon of a dolphin (you can see this – it’s the big off-center lump on their foreheads) focuses their echolocation sounds, and may have just as much to do with collecting the sounds bounced back from echolocated objects. They do also have regular ears, and their ability to hear is among the best in the mammalian world.

Other Dolphin Senses

Dolphins are very sensory, and will seek out touch from other dolphins as well as from humans. They do not, however, have strong senses of smell or taste. Their primary sensory input comes from sound.

It’s possible that dolphins also can sense magnetic fields well enough to use the earth’s magnetism to navigate, although this is a poorly-researched area.


Dolphin Sounds and Accoustics


Most people have heard the chirping, squeaking noises made by dolphins which they use to communicate with dolphins and human trainers, and to navigate by using echolocation, or figuring out where things are by bouncing sound off them. Did you know dolphins can use their echolocation to detect three-inch objects further away than the length of a football field? Or that the possibility of true language exists, according to the theories of some researchers?

Do Dolphins Have Language?

Whether or not dolphins have language is a matter for debate unless and until we humans figure out how to speak to them. But evidence is mounting that dolphins may indeed have their own language.

Pods of dolphins in the English Channel stay on their own side – the French-water dolphins on the France side and the English-water dolphins on the England side – even though they are of exactly the same species and might be expected to mingle more. Some researchers say that this indicates not just language, but that two groups have developed distinct language that can’t be understood by the others.

Whether you buy that or not, there is a lot of research on dolphin vocabulary that indicates they communicate with at least as much sophistication as the higher apes. They have a vocabulary of danger sounds, food sounds, and seeking sounds, and sometimes put these sounds together in a reasonably complex fashion. There is also evidence that they may greet one another by name; specific sounds are only uttered when meeting certain dolphins. Dolphins and Man-Made Sonar

Because of millions of years of evolution, dolphin echolocation abilities are much superior to those of any man-made device. For this reason, the US Navy have been studying them for years in order to improve their own sonar. What they’ve found has been surprising.

Dolphins are incredibly good at distinguishing their own echolocation sonar even in very noisy underwater environments – and in fact are very good at locating the drift nets that entangle and kill so many of them, raising the question of why they are still often trapped in them. It has also been found, though, that some noisy locations confuse dolphins, perhaps explaining why dolphins often ground themselves in areas where Navy ships using active sonar are performing maneuvers. Could the clumsier man-made sonar be using frequencies the dolphins associate with something else? Or perhaps it’s like looking into a strobe light for them. Whatever the explanation, the Navy is interested in eradicating the problem.

Dolphin Beaching

It’s the most tragic thing a dolphin lover can see: a pod of dolphins that have apparently killed themselves by swimming onto a beach and lodging themselves there. Why do dolphins do this?

The most prominent theory currently is that something confuses their echolocation, “blinding” them to the location of the beach in relation to the open ocean. Since many beachings happen near man-made sonar activity, it’s possible that this impacts them. Some very recent autopsies of beached dolphin bodies show a very high percentage of damaged hearing, suggesting that a very powerful sound somewhere may have basically blown out their hearing. Dolphins see quite well, but without their ears they are disoriented and blinded. And when one dolphin beaches itself, the others are at risk because they will try to help him

However a beaching is initiated, it’s likely that it has much to do with how a dolphin perceives sound. Hopefully, we’ll soon understand enough about dolphin hearing to be able to prevent these tragedies.



i will post more later on :D



Oh My Gosh!! Thanks, Dolphins Are so Cheerful and Cute ^x^
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lol thats good
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sorry long time no post >.>

Date: 7/5/09

Bottlenose Dolphins

Interesting Facts about Bottlenose Dolphins


Unlike some dolphins, the Bottlenose Dolphins have moved into almost every area of the ocean. You can find them in the Pacific, Atlantic or Indian Ocean waters, as well as in gulfs and river mouths located around the world. Not only do they have a larger area of living, but also are known to migrate into different eco-types, causing their range of living to be expansive, dependent on the season.

Scientists are now finding that there are more than one type of Bottlenose Dolphins that are inhabiting the various areas of the earth. This is based on the area in which they dwell, specifically divided by the Indo – Pacific area and the more common areas. There are also other species living closer to the Pacific which will slightly differ and the Black Sea dolphin. Despite their division of habitat, they are known to swim together in pods, or groups, in order to survive.

One of the well known attributes of these animals is the sonar senses that they have. This allows them to listen to sounds and echoes in order to find food as well as areas in which they want to travel or don't want to travel. This particular attribute links to their strong survival and ability to remain sensitive to what is surrounding them. Even though their sense of eyesight and smell is poor, the sonar sense has allowed them to find their way around the ocean in order to find areas of habitat and food.


Feeding



In the ocean deep, are plenty of options for a Bottlenose Dolphin that have a strong appetite. Fish, squid and other smaller sea life are the main staple of these dolphins, with a consumption of up to 30 pounds of food per day. One of the advantages that these dolphins have is with their hunting techniques. While some may find their food alone, they will be more likely to travel in groups which will herd the fish into a mud bank, then all will be able to eat at their own pace.


Reproduction


Bottlenose Dolphins have a strong mating ritual in order to communicate with each other. Typically, the dolphins will not reach maturity until they are ten to fifteen years old, with females becoming mature quicker than males. The females will remain pregnant for an average of twelve months. When the calf is born, there will be assistance from the other dolphins, similar to a midwife. The female will take care of a calf for up to 6 years, which is longer than most other dolphins. Some calves are also known to remain close to their mothers for a much longer time frame. The first year to year and a half will be spent nursing the calf.


Anatomy


It is the anatomy of the Bottlenose Dolphin that gives it the name, as well as it's distinguishing features. While many dolphins will have larger noses, the Bottlenose Dolphin is set apart because of it's smaller beak. This is because of the way that it feeds as well as it's adaptation into the ocean.

In order to compensate for this, Bottlenose Dolphins have developed a different type of vertebrae than others. This is one that is not attached together along the back. This allows for the dolphins to be flexible in their movements and to twist, turn and flip in more than one way.

The Bottlenose Dolphin is also known because it is one of the larger species of dolphins. They can get to be between 8 and 12 feet and can weigh up to 1500 pounds. This makes them a stockier type of dolphin that is also longer in size, with the males being much larger than the females.

Conclusion


As one of the most popular ocean creatures, the Bottlenose Dolphin shows it's attributes and characteristics that are similar to other dolphins, but have allowed for it's strong survival throughout the world. The capacities of this species to work and live in certain ways has allowed it to become one of the most loved fish of the deep sea.


next week topic will be about..:

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19/05/09
when i read through the page i noticed it doesnt much info so i added the ganges river dolphin as well :D

chinese river dolphin


The Yangtze River dolphin, commonly known as the Chinese River dolphin or the Baiji dolphin, is at the brink of extinction. In 1975, the Chinese government declared the Baiji a national treasure, and began to offer conservation and protection to the species, however, this has done little good, as the dolphin is still endangered by heavy boat traffic, fishing, industrial development, and the construction of the world's largest dam. The Yangtze River, where the Chinese River dolphin makes it's home is one of the world's busiest rivers in the most populated country on the planet. The Chinese River dolphin grows to be between four and eight feet, and can weigh up to 360 pounds.


Ganges River Dolphin

Introduction


If you are moving through India or Nepal, you can stop by the river banks of the Ganges in order to find the rare species of the Ganges River Dolphin. This dolphin is unique because of it's features as well as the way that it lives, allowing it to become recognized as a river specimen worth looking into.

"The Ganges River Dolphin can only be found in the fresh water rivers of Bangladesh, India, and Nepal."


Top Facts



While some types of dolphins can move swiftly in order to capture their food, the Ganges River Dolphin distinguishes itself by moving slower than other species. For this reason, they will feed in different ways and will always remain closer to the bottom of the river beds.

One of the distinguishing features of the Ganges river dolphins is their capacity to adapt to the changes that happen with the Ganges river. Specifically, the dolphins are known to migrate into different areas of the river when flood season is occurring. At other times, they are found closer to canals and places in which rivers join in order to survive. Much of this is dependent not only on the season, but also on whether the dolphin is traveling with others or is alone.

Like many other dolphin species, this one is also in deep danger of becoming extinct, and has been on the endangered species list since the 1950s. This is attributed to hunting and fishing in the area. However, it is also known that this dolphin lives in one of the most densely populated areas on the planet. This is causing problems with the ecology of the water and is stifling the habitat in which the Ganges River Dolphin can live.


Feeding


The diet of Ganges River Dolphins includes a wide range of fish, turtles and birds that are located around the Ganges river. They are more diverse in their eating habits than other river dwelling dolphins, including diets such as catfish, carp, clams, turtles and occasionally birds.

Because this species likes to dwell in the deeper parts of the river, it will also try to find most of it's food in a similar area. This is done by swimming close to the bottom of the river floor sideways, while opening it's snout whenever food is seen close by.


Reproduction


The Ganges River Dolphin will only have one calf at a time. Typically, the Ganges River Dolphin will mature at an older age, with females not becoming ready to breed until they are at an average of six to ten years old.

The Ganges River Dolphin will breed in a similar way to other dolphins, which includes breeding during the beginning of the year, and remaining pregnant for an average of 10 – 12 months.

After a calf is born, they will remain with their mother for one year. Typically, they will nurse for an average of two months, then start eating solid food; however, some will continue to nurse as well for up to one year.


Anatomy


Many consider the Ganges River Dolphin to be a sub-species of the Indus river dolphin. However, recent research has found a difference in appearances and has allowed the dolphin to remain as a separate species.

The attributes of this dolphin include a longer beak and large flippers.

They are also known because their body is somewhat larger than other species, not only in size, but also in weight. Even the smaller dolphins, which can be around five feet, will be able to get up to a weight that is at an average of 200 pounds. This makes them a large species dolphin, and distinguishes them from other types of dolphins.


Conclusion

The uniqueness of this dolphin is on the way that it has built it's survival methods and habitat. While some of the attributes are similar to other dolphins, it has also built a distinguishing way of setting itself apart as one of the great species of river dolphins.

next weeks topic:
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28.05.09

Indus River Dolphin


The Indus River dolphin is gray-brown, with a pink belly. It grows to be between five and eight feet, and can weigh up to 200 pounds. The Indus River dolphin is only known to exist in the Punjab Province and the Sind Province of the Indus River. Due to its decline in population, the government of Sind, in Pakistan, has given the Indus River dolphin full legal protection, and has also established the Indus River Dolphin Reserve.


Introduction


The Indus River dolphin is a species that lives in the Ganges and Indus river, close to India, Nepal and Pakistan. It's growth into a freshwater species of dolphin is one that has allowed it to remain a unique classification and has created it's known attributes throughout the rivers of these countries.



"The Indus River Dolphin is only known to exist in the Punjab and Sind Provinces of the Indus River"


Top Facts


Until 1998, the Indus River dolphin was considered a sub-species of the Gangus River dolphin. Because both live in close proximity to each other and because of the features that cause them to be similar in the way in which they live, the separation was one that was not recognized until recently. The distinguishing attributes of this dolphin come from where it lives, specifically because it has moved into the Indus River of Pakistan, as well as some of the anatomy attributes that it has.

Unlike other river dwelling dolphins, the Indus River Dolphin stays somewhere in between being an ocean creature and a river dolphin. This is because they will come up for air every 30 seconds to two minutes. This causes them to move more frequently through the river spaces than other species. They also move in relation to migration, depending on the monsoon season and the dry season. This will cause them to either move towards the middle area of the river or downstream, where the river is more calm.


Feeding


The Indus River Dolphin feeds in the same way as the Ganges River Dolphin. Because of their poor eyesight, as well as their need to stay in the deeper areas of the river, they prefer to find their food on the river bottom. They will do this by swimming to one side, and simply opening their mouth whenever they sense that there is food near.

The diet of the Indus River Dolphin includes the river dwelling creatures that are close to the area that they are swimming. This includes a wide variety of fish, such as carp and catfish, as well as turtles, prawns and sometimes birds. This is dependent on what is found while they are swimming closer to the river bottom. When they come up for their air; however, they will often times find extra food that is more suitable.


Reproduction


The reproduction features of the Indus River Dolphin are similar to others of the dolphin species. Specifically, this means that they will begin to sexually mature by the time they are six to ten years old. Mating rituals will lead most pregnancies to occur between the months of January to April, while carrying their calf in the embryo for a period of 10 – 12 months, depending on the development cycle needed. Calves will remain with their mother and will continue to nurse for up to one year. They will not leave their mother until they are an average of two years old, which will then lead them to either move on their own or to meet other dolphins that are of similar age.


Anatomy


The appearance of the Indus River Dolphins includes stocky features of their body. They are an average size of five to eight feet, and will typically weight around 200 pounds. They are also noticed by their thin and long beaks, which is what helps them to feed on the bottom of the river beds.

Conclusion


The features of the Indus River Dolphins has allowed them to become their own species and to develop throughout the various areas of the Eastern countries. Through their abilities to adapt to the river beds throughout India and Pakistan are also their recognized capacity to survive in a different manner than most dolphins.


ahh well this dolphin is quite intresting any next week will be the last species of dolphin...
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