So, just what do dolphins do?
Dolphins are very sociable animals and live in groups comprised of a single sex, or a mixed group of males, females and their young calves. They also help each other when hunting, giving birth or when sick, so their friendly and co-operative behaviour is actually a vital part of social bonding and species survival. They also spend a large part of the day in play including the adult males!
Dolphins use whistles and clicks to communicate with each other. It is not yet known how complicated this language is, but they undoubtedly recognise and respond to one another.
Breeding
Dolphins usually mate in the spring and the summer, and the females give birth underwater to a single calf 10 to 12 months later
Two, and sometimes even more, dolphin 'midwives' surround the mother to help with the delivery and also to protect her and the new born calf from attack by sharks attracted to blood shed during the birthing process. Sometimes, the midwives will gently tug at the baby's tail as it emerges while whistling encouragement to both mother and youngster. Then, as a group, they move together in order to help guide the new born to the surface so that it can take its first, vital breath of air. However, female dolphins are still quite capable of giving birth without the assistance of others.
Once the calf is born, it will suckle 3.4 liters of milk every day for 9 months or less. Baby dolphins do not have lips and since they are unable to suckle the nipple, they hit it with their rostrum (beak) until the milk is ejected. The dolphin mother will nurse her calf for at least 16 months, so she generally comes into breeding condition once every two to three years. Each time she does breed it is likely to be with a different male.
This kind of social help also extends to injured dolphins too. An injured dolphins cries of distress will summon instant aid from other dolphins in the vacinity. They will then try and carry or support the injured dolphin in the water so that it is able to reach the surface and breathe
What do dolphins eat?
The worlds dolphin populations are made up from almost forty species varying in size from 1.2 m and 40 for the Maui's dolphin, and up to 9.5 m and 10 tonnes for the killer whale. They are found worldwide, mostly in the shallower seas of the continental shelf. So clearly, with this much variation within the dolphin family, you can expect the same variation in each species diet.
So, while some dolphins eat fishes like herring, cod or mackerel, others species will prefer to eat squids.
Of course, the largest of all the dolphin species - the killer whales - will also eat marine mammals like seals or sea lions and sometime even turtles.
Usually, the amount of fish that they eat depends on the kind of fish that they hunt. While mackerel or herring will contain a lot of fatty oils in their bodies, squid will not have so much, therefore, to get enough energy required for their activities, dolphins will have to eat a lot more squid than mackerel.
On average, a dolphin with a weigh of 200 to 250 Kg will eat between 10 and 25 Kg of fish every day
How do dolphins catch their food
One common feeding method is herding, where a pod squeezes a school of fish into a small volume, known as a bait ball. Individual members then take turns ploughing through the ball, feeding on the stunned fish.
Corralling is another method where dolphins chase fish into shallow water to more easily catch them. In South Carolina, the Atlantic bottlenose dolphin takes this further with "strand feeding", driving prey onto mud banks for easy access.
In some places, orcas come to the beach to capture sea lions. Some species also hit fish with their tails, stunning them and sometimes knocking them out of the water.
Dolphin communication
Dolphins are capable of making a broad range of sounds using nasal airsacs located just below the blowhole. There are roughly three categories of sounds can be identified: frequency modulated whistles, burst-pulsed sounds and clicks. Dolphins communicate with whistle-like sounds produced by vibrating specialised connective tissue - similar to how human vocal cords function, and through burst-pulsed sounds. However, the nature and extent of that ability is not known.
The clicks are directional and are for echolocation, often occurring in a short series called a click train. The click rate increases when approaching an object of interest. Amazingly, dolphin echolocation clicks are amongst the loudest sounds made by marine animals!
In 2011 researchers in the United States and Great Britain have been using a CymaScope to find out more - a CymaScope is an instrument which produces visible patterns from sound. They have found that part of dolphin communication consists of receiving and transmitting sound pictures. It is almost certain that to this ability is shared by the entire dolphin family
Can humans communicate with dolphins?
communicating with each other. In an effort to enhance human dolphin communication, he began to use computers to translate human words into dolphin whistles and to send messages back. Unfortunately,much of his experimental work has never been published.
In one Lilly experiment, a woman lived in a pool with a bottlenose dolphin named Peter as her only companion for several months. Sleeping in a bed above the pool, she was ever on call. Communication attempts were often transing sessions, where the woman attempted to teach language to the dolphin. Peter was reportedly a demanding 'roommate', and the woman eventually withdrew from the project. While a basic communication did develop, reportedly similar to that between a dog and a human, deeper exchanges - of dolphin whistles or human words - did not occur.
Lilly's work ended in the 1980s. Since then, researchers led by Louis M. Herman have developed a new approach to communication studies with captive bottlenose dolphins at the University of Hawaii. Their goals have been to discover how dolphins process information - both through sight and sound, how they learn, and how they communicate. Herman's research has verified earlier findings that dolphins have good memories and can mimic a wide variety of sounds. Able to store new information, they can also quickly update old information.
time, the dolphin responded correctly. If the list was shortened, however, to one or two sounds, the results were 90 percent correct. Like humans given such tests, the dolphins found the recent items easiest to remember.
The dolphin's most impressive accomplishment is its ability to understand sentences expressed in either an artificial acoustic or a visual language. In the experiments, the "words" of the language are sounds generated by a computer and broadcast via an underwater speaker. First the dolphin learns words such as fetch, ball and hoop. The words refer to (1) objects in the tank; (2) actions that might be taken in connection with the objects; and (3) modifiers of place or location. In "sentences" of two or more words, the dolphin is then told to do something. The level of understanding is measured by the accuracy and reliability with which the dolphin carries out the instruction.
Dolphins perform very well on such tests. To more than 600 two-word sentence instructions, the dolphins gave correct responses about 80 percent of the time. They also understood "new" instructions almost as well as familiar ones, with only a slight advantage to the familiar. New instructions consisted of fresh combinations of words that either obeyed the language rules or, in a few cases, were logical extensions of existing rules.
Gradually, the dolphins seemed to master sentence form and use. They were taught to respond to sentences up to five words long. Then visual symbols or gestures, as well as auditory signals, were tried. Comprehension for a dolphin trained with visuals was the same as that for a dolphin trained with sound.
These and other experiments clearly show that dolphins can learn rules and understand certain abstract concepts. They can also work with both auditory and visual symbols. Compared to apes which have been taught to use America sign language - an exclusively visual medium for communication - the dolphins have more range. The apes, on the other hand, learn more quickly in tests involving symbols. Of course, all of these are laboratory feats and prove nothing about life in the wild - for dolphins or apes.
In the future, trained dolphins may be able to grasp more complex human-taught vocabularies. But this does not necessarily mean that dolphins have their own language. No-one yet knows where this research will lead, but many scientists feel that we have only glimpst what really goes on inside the mind of a wild dolphin.
Can dolphins kill sharks?
Dolphins and many shark species are similar in shape and size, and inhabit the same regions and depths of the ocean. Sharks have a reputation for being fierce predators. hardly surprising when they are armed with rows of sharp serrated teeth that can easily bite through flesh and bone. Unlike dolphins, sharks have a very tough, sandpaper-like skin that is not easily punctured.
Dolphins, on the other hand, are seen as intelligent, playful creatures. They only have a single row of peg-like teeth which is mainly used for catching smaller fish. Their skin is soft, flexible and can be cut easily.
So at face value, it would seem that sharks would have the edge over a dolphin in a face to face fight - but all is not as it seems!Since dolphins normally travel together in a group - known as a pod, if one of them is threatened by a shark, the other members of the group will join in to defend the dolphin that is in danger. The dolphin's main weapon is their snout, otherwise known as their beak. It is made of very strong and thick bone, and has a hard, rounded end.
If the pod decides to defend against a likely shark attack, the dolphins will circle the shark very rapidly from different directions. This causes the shark to become confused and is then unable to choose a specific dolphin to chase. When a dolphin becomes suitably positioned below a shark - usually at a distance of several meters, the dolphin will make a sudden rush at the shark's softer underbelly ramming it with his snout. This has the effect is like an extremely powerful punch. The shark can be seriously injured with a single blow, and they are often stunned or knocked unconscious. The dolphins will sometimes repeatedly ram a shark that has been very aggressive, and are quite capable of killing a large, dangerous shark.However, attacking dangerous sharks clearly has an element of serious risk and so dolphins are often unwilling to attack the 'bigger boys' such as white sharks, tiger sharks, mako sharks and bull sharks, unless of course they have good reason to ie. protecting pregnant females, calves or injured individuals.
Dolphins are very sociable animals and live in groups comprised of a single sex, or a mixed group of males, females and their young calves. They also help each other when hunting, giving birth or when sick, so their friendly and co-operative behaviour is actually a vital part of social bonding and species survival. They also spend a large part of the day in play including the adult males!Dolphins use whistles and clicks to communicate with each other. It is not yet known how complicated this language is, but they undoubtedly recognise and respond to one another.
Breeding
Dolphins usually mate in the spring and the summer, and the females give birth underwater to a single calf 10 to 12 months later
Two, and sometimes even more, dolphin 'midwives' surround the mother to help with the delivery and also to protect her and the new born calf from attack by sharks attracted to blood shed during the birthing process. Sometimes, the midwives will gently tug at the baby's tail as it emerges while whistling encouragement to both mother and youngster. Then, as a group, they move together in order to help guide the new born to the surface so that it can take its first, vital breath of air. However, female dolphins are still quite capable of giving birth without the assistance of others.Once the calf is born, it will suckle 3.4 liters of milk every day for 9 months or less. Baby dolphins do not have lips and since they are unable to suckle the nipple, they hit it with their rostrum (beak) until the milk is ejected. The dolphin mother will nurse her calf for at least 16 months, so she generally comes into breeding condition once every two to three years. Each time she does breed it is likely to be with a different male.
This kind of social help also extends to injured dolphins too. An injured dolphins cries of distress will summon instant aid from other dolphins in the vacinity. They will then try and carry or support the injured dolphin in the water so that it is able to reach the surface and breathe
What do dolphins eat?
The worlds dolphin populations are made up from almost forty species varying in size from 1.2 m and 40 for the Maui's dolphin, and up to 9.5 m and 10 tonnes for the killer whale. They are found worldwide, mostly in the shallower seas of the continental shelf. So clearly, with this much variation within the dolphin family, you can expect the same variation in each species diet.
So, while some dolphins eat fishes like herring, cod or mackerel, others species will prefer to eat squids.
Of course, the largest of all the dolphin species - the killer whales - will also eat marine mammals like seals or sea lions and sometime even turtles.
Usually, the amount of fish that they eat depends on the kind of fish that they hunt. While mackerel or herring will contain a lot of fatty oils in their bodies, squid will not have so much, therefore, to get enough energy required for their activities, dolphins will have to eat a lot more squid than mackerel.On average, a dolphin with a weigh of 200 to 250 Kg will eat between 10 and 25 Kg of fish every day
How do dolphins catch their food
One common feeding method is herding, where a pod squeezes a school of fish into a small volume, known as a bait ball. Individual members then take turns ploughing through the ball, feeding on the stunned fish. Corralling is another method where dolphins chase fish into shallow water to more easily catch them. In South Carolina, the Atlantic bottlenose dolphin takes this further with "strand feeding", driving prey onto mud banks for easy access.
In some places, orcas come to the beach to capture sea lions. Some species also hit fish with their tails, stunning them and sometimes knocking them out of the water.
Dolphin communication
Dolphins are capable of making a broad range of sounds using nasal airsacs located just below the blowhole. There are roughly three categories of sounds can be identified: frequency modulated whistles, burst-pulsed sounds and clicks. Dolphins communicate with whistle-like sounds produced by vibrating specialised connective tissue - similar to how human vocal cords function, and through burst-pulsed sounds. However, the nature and extent of that ability is not known. The clicks are directional and are for echolocation, often occurring in a short series called a click train. The click rate increases when approaching an object of interest. Amazingly, dolphin echolocation clicks are amongst the loudest sounds made by marine animals!
In 2011 researchers in the United States and Great Britain have been using a CymaScope to find out more - a CymaScope is an instrument which produces visible patterns from sound. They have found that part of dolphin communication consists of receiving and transmitting sound pictures. It is almost certain that to this ability is shared by the entire dolphin family
Can humans communicate with dolphins?
communicating with each other. In an effort to enhance human dolphin communication, he began to use computers to translate human words into dolphin whistles and to send messages back. Unfortunately,much of his experimental work has never been published. In one Lilly experiment, a woman lived in a pool with a bottlenose dolphin named Peter as her only companion for several months. Sleeping in a bed above the pool, she was ever on call. Communication attempts were often transing sessions, where the woman attempted to teach language to the dolphin. Peter was reportedly a demanding 'roommate', and the woman eventually withdrew from the project. While a basic communication did develop, reportedly similar to that between a dog and a human, deeper exchanges - of dolphin whistles or human words - did not occur.
Lilly's work ended in the 1980s. Since then, researchers led by Louis M. Herman have developed a new approach to communication studies with captive bottlenose dolphins at the University of Hawaii. Their goals have been to discover how dolphins process information - both through sight and sound, how they learn, and how they communicate. Herman's research has verified earlier findings that dolphins have good memories and can mimic a wide variety of sounds. Able to store new information, they can also quickly update old information.
time, the dolphin responded correctly. If the list was shortened, however, to one or two sounds, the results were 90 percent correct. Like humans given such tests, the dolphins found the recent items easiest to remember.
The dolphin's most impressive accomplishment is its ability to understand sentences expressed in either an artificial acoustic or a visual language. In the experiments, the "words" of the language are sounds generated by a computer and broadcast via an underwater speaker. First the dolphin learns words such as fetch, ball and hoop. The words refer to (1) objects in the tank; (2) actions that might be taken in connection with the objects; and (3) modifiers of place or location. In "sentences" of two or more words, the dolphin is then told to do something. The level of understanding is measured by the accuracy and reliability with which the dolphin carries out the instruction.
Dolphins perform very well on such tests. To more than 600 two-word sentence instructions, the dolphins gave correct responses about 80 percent of the time. They also understood "new" instructions almost as well as familiar ones, with only a slight advantage to the familiar. New instructions consisted of fresh combinations of words that either obeyed the language rules or, in a few cases, were logical extensions of existing rules.
Gradually, the dolphins seemed to master sentence form and use. They were taught to respond to sentences up to five words long. Then visual symbols or gestures, as well as auditory signals, were tried. Comprehension for a dolphin trained with visuals was the same as that for a dolphin trained with sound. These and other experiments clearly show that dolphins can learn rules and understand certain abstract concepts. They can also work with both auditory and visual symbols. Compared to apes which have been taught to use America sign language - an exclusively visual medium for communication - the dolphins have more range. The apes, on the other hand, learn more quickly in tests involving symbols. Of course, all of these are laboratory feats and prove nothing about life in the wild - for dolphins or apes.
In the future, trained dolphins may be able to grasp more complex human-taught vocabularies. But this does not necessarily mean that dolphins have their own language. No-one yet knows where this research will lead, but many scientists feel that we have only glimpst what really goes on inside the mind of a wild dolphin.
Can dolphins kill sharks?
Dolphins and many shark species are similar in shape and size, and inhabit the same regions and depths of the ocean. Sharks have a reputation for being fierce predators. hardly surprising when they are armed with rows of sharp serrated teeth that can easily bite through flesh and bone. Unlike dolphins, sharks have a very tough, sandpaper-like skin that is not easily punctured.
Dolphins, on the other hand, are seen as intelligent, playful creatures. They only have a single row of peg-like teeth which is mainly used for catching smaller fish. Their skin is soft, flexible and can be cut easily.
So at face value, it would seem that sharks would have the edge over a dolphin in a face to face fight - but all is not as it seems!Since dolphins normally travel together in a group - known as a pod, if one of them is threatened by a shark, the other members of the group will join in to defend the dolphin that is in danger. The dolphin's main weapon is their snout, otherwise known as their beak. It is made of very strong and thick bone, and has a hard, rounded end.
If the pod decides to defend against a likely shark attack, the dolphins will circle the shark very rapidly from different directions. This causes the shark to become confused and is then unable to choose a specific dolphin to chase. When a dolphin becomes suitably positioned below a shark - usually at a distance of several meters, the dolphin will make a sudden rush at the shark's softer underbelly ramming it with his snout. This has the effect is like an extremely powerful punch. The shark can be seriously injured with a single blow, and they are often stunned or knocked unconscious. The dolphins will sometimes repeatedly ram a shark that has been very aggressive, and are quite capable of killing a large, dangerous shark.However, attacking dangerous sharks clearly has an element of serious risk and so dolphins are often unwilling to attack the 'bigger boys' such as white sharks, tiger sharks, mako sharks and bull sharks, unless of course they have good reason to ie. protecting pregnant females, calves or injured individuals.