Dolphins

"No arguments can rationalize the forced confinement of these social and highly intelligent creatures", said Richard O'Barry1. He is very right. Dolphins are one of the most social and intelligent creatures in the world. Some people think that they may be smarter then even chimpanzees. Their intelligence has been tested many times over and they have been found to be able to do arithmetic and memory games. Dolphins are very socially sophisticated creatures. They have a complex language, which is in areas comparable to the language of humans. They have the ability of echolocation, which has many uses. Their ability to use echolocation has even helped humans, mainly in the military. Finally dolphins are very social animals. They have complex social grouping and have many emotions.

"...Cetaceans (dolphins) communicate over hundreds of miles, making theirs a truly global society. Surrounded by this universal conductor of communication, marine mammals develop unusually strong bonds to one another. Individuals depend heavily on their position within the group, or "pod," for their identity..." says Jean-Michel Cousteau abut dolphins and their communication. Dolphins communicate using an extensive system of whistles, which are similar to human voices. (Jean-Jean-Michel, 2000)

"Each herd of dolphins has its own sound signature"(Au, 1993) this allows the dolphins to tell each other. The unique whistle of each herd is called its "coda". An example of how dolphins use these "coda" is when they dive for food. When they dive as a group, they often fan out in search of food. When they are done, they congregate using their clicking sounds. Dolphins can also use their whistling to manipulate situations. It seems as if though dolphins have problem solving skills. French aquanaut and Film-maker Jacques-Yves Cousteau and his crew trailed a heard of dolphins. The herd seemed to be comprised of a few males and one male. As they approached the herd, they heard many soft clicks. As they got closer, everything changed. "They heard a very loud burst of clicks from the large male. The rest of the group fell silent. The male sidled up to Cousteau's ship and spouted for all he was worth. He seemed to be deliberately making himself conspicuous, drawing the researchers away. Meanwhile, the female dolphins exited in the opposite direction."(Bright, 1997) The male dolphin then continued on to dash away from the researchers and rejoins his herd. The dolphin male had sensed danger and had communicated with the rest of his herd what he was about to do. They solved this problem using different frequencies of whistling.

"Echolocation - the location of objects by their echoes - is a highly specialized faculty that enables dolphins to explore their environment and search out their prey in a watery world where sight is often of little use. As sound travels four and a half times faster in water than in air, the dolphin's brain must be extremely well adapted in order to make a rapid analysis of the complicated information provided by the echoes."(Hillix, 2003) As said in the book, dolphins are able to do many things simply by using their ability of echolocation. It helps them navigate, hunt, and even kill their prey.

The dolphin is able to generate sound in the form of clicks. The frequency of this click is higher than that of the sounds used for communication and differs between species. When the sound strikes an object, some of the energy of the sound wave is reflected back towards the dolphin. As soon as an echo is received, the dolphin generates another click. "The time lapse between click and echo enables the dolphin to evaluate the distance between it and the object; the varying strength of the signal as it is received on the two sides of the dolphin's head enable it to evaluate direction." (Au, 1993) By continuously emitting clicks and receiving echoes in these ways, the dolphin can track objects and home in on them. Echolocation is how dolphins navigate. They "see" distant underwater terrain using sound as clearly as we see the above water terrain using our eyes. Their complex sonar can tell the shape, speed, and density of the object that they are racing towards. This allows them to navigate, because they are able to detect when they might hit a large object or they may have it in their memory of where they are. Dolphin's echolocation also has the ability to kill or stun their prey. "...that dolphins close to herring would emit low bangs at the frequency the fish hear best at, and had suggested the bangs were designed to damage the fish's hearing apparatus. He has now taped a dolphin emitting a sequence of low- frequency "bangs" while chasing a fish."(ABC.net, 2001) In this case, it was shown that dolphins had used their sonar ability, or echolocation, to stun a fish. The dolphins recognize the frequency at which the fish hear at, and give a low bang towards the fish. This stuns the fish, and aids with the dolphins hunting. Other evidence states that dolphins may even be able to kill their prey with these bangs of sound. "She recorded wild Atlantic spotted dolphins emitting a medium-frequency buzz while searching for prey in sand on the seabed. She says buried eels jumped out of the sand, and either stopped completely or moved sluggishly as if they were stunned, giving the dolphin time to catch them."(ABC.net, 2001) In this case, the dolphins used their sonar to detect their prey and then stun or kill it at the same time. The eels were shocked out of their hiding, where the shock of being disturbed by the buzz stunned them or in some cases killed them. This is extremely Beneficial to dolphins, for it will make their hunting much easier.

Finally, dolphins are extremely social. "Dolphins are highly social animals and live in family groups called pods, the social organizations of pods can be very complex, it varies between species and even within species living in different parts

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