Download The dolphin is a very intelligent creature of the sea

Dolphins: Adaptations for Life, the Ocean and their Intelligence
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Dolphins: A look into adaptations for life, the ocean and insight into their intelligence.
Dolphins: Adaptations for Life, the Ocean and their Intelligence
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Introduction
The dolphin is a very intelligent creature of the sea. A common misconception by
many is that dolphins are fish. This is however very inaccurate as dolphins are indeed
mammals like man. They are warm blooded and give birth to a calf that is born alive and
that is suckled by the mother. These animals are very sociable and live in groups known as
pods where they can interact freely with other dolphins and at times even dolphins from
other pods.
Adaptations for Life in the Ocean
The dolphin has as an asset a very powerful tail fluke that provides it with an
upward and a downward movement that is very powerful and that assists in rapid
swimming. They are able to use their tails when they are hunting as well as they can hit
fleeing prey up in the air with their tails and stun the fish. They are then able to scoop the
fish up when they fall. They also utilize the tail as a warning mechanism that is able to alert
other dolphins of impending danger or of annoyance.
The pectoral fins in addition to being used to steer through the water are also used
to increase social contact. They often stroke each other with these fins and are able to use
these fins to bond with each other. There have been observations where, “dolphin "friends"
may swim along face to face touching flippers” (Kirby). The dolphins that are close to one
another will often display behavior such as synchronized swimming where they turn and
twist in harmony.
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The teeth of the dolphin are interlocking rows of pegs that are able to hold slippery
fish. The fish are consumed whole and typically head first. Several behaviors that are
displayed in the wild and that are signs of aggression are not considered this way in
dolphins that are in captivity. Some of these include an open mouth, head nodding and jaw
clapping.
Breathing is accomplished through the blowhole on the tops of their heads
(Common Dolphin, EOA). The emptying and filling of the lungs occurs in as little as a fifth
of a second. The air in the blowhole leaves at very high speeds. There are also sensory
nerve endings around the blowhole that are able to sense pressure changes and this enables
the dolphin to determine exactly when to open the blowhole as they are able to sense when
the surface is approaching. It is possible for a dolphin to drown if water gets into the
blowhole so there are powerful muscles that close the blowhole when they dive under
water. The eyes of a dolphin are protected from damage from objects and friction by a
special secretion that is produced by the eyes.
Even in sleeping there are special adaptations that the dolphin has to live in the
marine environment. The dolphin will only shut down half its brain when sleeping as
breathing is under voluntary control. They take short naps and float below the surface so
they can rise slowly and breathe. Activity is often dependent on the preferred feeding habits
as some dolphins actually feed at night._________________________________________
Dolphins have skin that is very smooth (Dolphin, EOA) and allows the dolphin to
move easily through the water and reduces heat loss. The skin may bear marks from other
dolphins due to rough play or mating and even from sunburn if they are stranded. The body
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of a dolphin is very streamlined and as such they are aided in the fact that they are able to
achieve high swimming speeds. This is exemplified by the form of the ears. The ears are
very unnoticeable and are located a few centimeters after the eyes. It is a small hole only a
few millimeters in diameter. _________________________________________________
The dolphin uses its adaptations to its advantage and as they are capable of diving
to great depths and leaping to great heights this helps in avoiding predators and in proving
strength to females in mating. They also use splashing jumps to herd fish.
Dolphin Life
The gestation period for a dolphin to be born is about 12 months but varies
according to species. The young are carried in the womb and are born alive. The calf is
born tail first (Dolphin, EOA) and will suckle the mother for as much as four years though
this may also vary greatly dependent on circumstances. A baby calf can stay with the
mother for between 3 and 6 years. During this period they will learn feeding techniques,
social interaction and group foraging. It is likely that females will remain with the pod with
the mother and sisters but males will leave and interact with other males.
They possess defined home ranges and will roam and feed in this area typically.
They may venture out of their home range in some circumstances such as a shortage of
food or if the conditions in the area force them to expand their home range.
The social component of dolphins is exemplified by the fact that they will actually
assist another dolphin that is in trouble. If another dolphin is sick and is drowning the
dolphins will support this one with their bodies and keep it afloat with the blowhole above
the water so it can breathe.
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The major predators of the dolphin are few but consist of sharks and man. Man has
exploited the dolphin and has killed dolphins for food, in netting, due to pollution and
fishing.
In a typical day in the life of a dolphin a large portion of the day is dedicated to the
search for sustenance. They seek food and actually feed. They may do this alone or
together as a pod. The use of echolocation in dolphins (Whitlow) for hunting helps locate
fish by the stream of pulses and clicks that they produce. They also communicate with
whistling and body language. It is believed that each dolphin has its own individual whistle
signature that is akin to a name and that they are identified by this whistle. A mother will
use imprinting with the newborn calf so that it is taught to recognize her whistle and
thereby identify her from the rest of the pod.
The birth of a calf can restrict the movements of the mother and as such the mother
is often assisted by other females in the pod. These are often females that do not have
offspring yet or that are incapable of reproducing. For younger females that have not
achieved sexual maturity the role of the surrogate mother is particularly useful as they are
prepared for when they have their own offspring. This behavior illustrates well the social
nature of these creatures and shows their intelligence.
The Intelligence Debate
There has been a large debate as to the intelligence of the dolphin. The dolphin has
a brain that is larger than the chimpanzee and the human brain. Their brain has a neocortex
area that is similar to the human brain where higher brain functions can take place. In this
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area memory, creativity, learning and judgment are typical. The relative size of the brain to
the body however is smaller than in humans and many say this means that the human being
is more intelligent than the dolphin.
There are several factors that can be considered in this argument however as the
dolphin possesses a layer of fatty tissue, called blubber, (Ganges Dolphin, EOA) to
maintain temperature. The dolphin design is also based on water where the rules are
different to land dwelling animals. Many also state that the echo-location system of the
dolphin accounts for the majority of brain space and that this means dolphins can never be
as intelligent as human. We must however again remember that the environment is acoustic
in nature and also the fact that the entire brain is not actually occupied by this as there are
also a lot of “"silent zones" -- areas where consciousness is located” (Reinartz).
The cerebellum is well developed in the brain of the dolphin and this is evident in
their coordination and balance. The thalamus is a central point for the nerves that reach the
cortex. Therefore these are cabling highways that connect the central nervous system. This
is better developed in dolphins than in humans. The hypothalamus hosts the automatic
nervous system. This area is incredibly large in humans in comparison to dolphins. The
dolphin controls more actions than the human being. An example of this is the fact that
they control every breath whereas in humans breathing is an involuntary action.
There are many features of the dolphin brain that indicate that it has the status of
being very intelligent. In comparisons features such as the “Grey-cell-coefficient” and the
“black brain substance” (Reinartz) are important in illustrating the intelligence of these
mammals. The “Grey-cell-coefficient” is a relationship between the mass of nerve cells and
the total brain mass. As the density of the nerve cells in the cortex decreases the
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intelligence of the creature is higher. This assists in providing proof that dolphins may in
fact be as intelligent as or more intelligent than humans.
The ‘black brain substance” is found in humans and dolphins. It is located in the
middle brain and is important as it produces neuro-transmitters that are needed for the
complex coordination of the body and also is involves other parts of the brain that are
associated with thoughts. It has also been perceived that dolphins can learn behaviors and
babies are trained to perform task.
The true nature of dolphins can be seen in their complex exchanges of information.
Their perception and communication is exceptional and therefore this shows that the
transmitters and receivers are adept at the transport of data.
The reality of dolphins and dolphin intelligence are being studied intensely by
scientist today. Studies in the past have focused on captive animals as they are easier to
monitor and assess. These studies may not reveal the true reality of dolphins however as
captive animals do not portray the same behavior in the wild.
More studies involving wild animals must be carried out to properly assess the
theory of the intelligence of the dolphin in comparison to primates. Wild animals may in
fact display more intelligent behavior than captive animals as they are in their natural
environment and are not subjected to additional stresses of being in captivity.
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Works Cited Page.
Whitlow, W.I.. The sonar of dolphins. Springer New York Inc., 1993. Accessed on Google
Book on April 28th 2007.
<http://books.google.com/books?hl=en&lr=&id=Q3MIsrPDA5EC&oi=fnd&pg=PR7&dq=
dolphins&ots=RBnXIBYXDD&sig=2eSMX1DfSGA2vY5wSSkN-JAAZpU#PPR4,M1>
The Ultimate Guide: Dolphins. Accessed on April 28th 2007.
<http://tursiops.org/dolfin/guide/weblinks.html>
Reinartz, U. TURSIOPS. Accessed on April 28th 2007.
<http://home.snafu.de/ulisses/tursiops.htm>
Kirby, S. Dolphins. Accessed on April 28th 2007.
http://www.southwest.com.au/~kirbyhs/dolphinsa.html
The Bottlenose Dolphin. Accessed on April 28th 2007.
<www.enchantedlearning.com/subjects/whales/spe...>
Encyclopedia of Animals: Dolphin. EBSCO Database. Accessed on April 28th 2007.
<http://search.ebscohost.com/login.aspx?direct=true&db=ani&AN=9500300040&site=eho
st-live>
Encyclopedia of Animals: Ganges Dolphin. EBSCO Database. Accessed on April 28th
2007. <
http://search.ebscohost.com/login.aspx?direct=true&db=ani&AN=9500300039&site=ehost
-live >
Encyclopedia of Animals: Common Dolphin. EBSCO Database. Accessed on April 28th
2007. <
http://search.ebscohost.com/login.aspx?direct=true&db=ani&AN=9500300043&site=ehost
-live >
Dolphins: Adaptations for Life, the Ocean and their Intelligence
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Fact Sheet:
(Bottlenose)
GENERAL DESCRIPTION
Dolphins are cetaceans that possess a beaklike snout and a falcate dorsal fin. They have
sharp teeth and breathe through a blowhole. Dolphins are commonly found in groups called
pods.
SHAPE AND FINS
The body of the dolphin is streamlined and the fins are shaped to accommodate powerful
and quick swimming. The dorsal fin is long and the flippers are broad and slightly pointed.
DIET AND TEETH
Dolphins feed mostly on fish and squid. They normally swallow the prey whole even
though they have sharp teeth.
PREDATORS OF DOLPHINS
Mainly man and sharks.