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Running head: AN EVALUATION OF THE ELEPHANT
An Evaluation of the Elephant Compared to Modern Domesticated Species
Karianna Gooding
Broadview University
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AN EVALUATION OF THE ELEPHANT
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Abstract
This essay will cover the following anatomical structures of the pachyderm: the musculoskeletal,
digestive, circulatory, respiratory, urinary, reproductive, and integumentary systems and some
interesting facts about the pachyderm’s behavior social system. Along with completing an
evaluation of the structure and function of each section of the elephant’s body, a compare and
contrast between the pachyderm and the canine, feline, bovine, and equine species will also
provide a unique guide to allowing the reader to visualize how unique the pachyderm is and how
evolution specialized this animal to its environment.
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An Evaluation of the Elephant Compared to Modern Domesticated Species
Biodiversity within the animal kingdom is as abundant as it is complex. This becomes
more and more evident as one delves into the veterinary and zoological sciences. These fields of
study offer the basic knowledge needed to classify and evaluate the multitude of organisms
found within the kingdom Animalia. With one’s knowledge of the diversity and likenesses with
the animals and their body systems, we can begin to understand what truly makes each species
unique. With that given, our purpose here will be to compare and contrast modern day domestic
species such as the bovine, equine, canine, and feline to the pachyderm. The animals’ systems
have likenesses by are different in various and interesting ways as a byproduct of each species’
evolution and speciation for its environment. The following evaluation will focus on: the
musculoskeletal, digestive, circulatory, respiratory, urinary, reproductive, and integumentary
systems and some interesting facts about the pachyderm’s behavior social system.
The first topic of discussion between the animals is the musculoskeletal system. In every
animal, the musculoskeletal system is the basic means for movement and support for the body.
Over two hundred bones comprise the entire skeletal system for the elephant (“Elephants move
like,” 2010). As a whole, the entire skeleton of the elephant is approximately 16.5 percent of the
entire weight of the animal’s possible two ton frame. This main support system for the massive
body is its appendicular skeleton, which includes its thoracic and pelvic limbs. The legs of the
elephant are more vertical in position than the angular limbs of the other quadrupeds, offering an
almost pillar like support for the enormous weight of the animal. Additionally, in the elephant’s
long bones, there is a lack of any marrow cavity which allows for stronger bones able to
withstand more pressure (“Elephant anatomy and,” n.d.). Conversely, if one has ever seen an
elephant walk, they appear to be flat-footed; however, much like the equine and bovine, the
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elephant walks on its tiptoes compared to a feline or canine which walks on its pads. It is noted
that the pad of an elephant is as diverse as the human fingerprint in that it is unique to that
particular animal; the pattern of the print can also be used to determine the age and overall size
of the elephant as well. Interestingly, the musculoskeletal system of the elephant allows it equal
power over all four limbs in an almost four by four function; other quadruped animals are only
known to power from their hind legs for acceleration (“Elephants move like,” 2010). This
essentially provides the elephant with great power for the locomotion of its massive frame. The
muscle system of the elephant as a whole is literally larger than most other species, from the
length and size of the muscle, to the size of the fibers that comprise the muscles themselves.
Comparatively, the main body bone structure of the elephant is much like any other
mammal with 19 to 20 pairs of ribs and a Cervical: 7, Thoracic: 20, Lumbar: 5, Sacral: 5, and
then a 24 to 33 tail vertebral pattern depending on the species. The elephant’s skull is very large
by also lightweight because of the pneumatization of the cranium; in other animals, only the
sinus cavities are pneumatic. The elephant’s most noticeable form of speciation is evident with
its large trunk. It has be thought to have evolved from fused muscles of the nose, upper lip, and
cheek. The trunk of the elephant has no bones but contains over 40,000 muscles divided into as
many as 150,000 individual units. The trunk contains both superficial and internal muscles. The
superficial muscles run longitudinally along dorsal ventral lateral aspects. The internal muscles
include radial and transverse muscles allowing the trunk to be as specialized as a finger but
strong enough to lift around 770 pounds (“Elephant anatomy and,” n.d.).
One of the most important functions of the elephant trunk is that it is a major structure of
the respiratory system of the animal. Within most mammals, there is a pleural cavity which
contains the lungs. The pleura usually aid an animal with breathing by exerting negative
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pressure on the lungs forcing them to expand for a breath. However, elephants do not have a
pleural cavity within their body. Because of this, the elephant’s lungs are connected directly to
the chest cavity wall, and the diaphragm and breathing is done so by flexing and relaxing of the
chest muscles. The elephant’s ability to breathe is still an autonomic function; yet, due to the
respiratory structure, if excessive pressure is applied to the chest cavity of the animal, it will
likely suffocate. Amazingly, even with this unique respiratory structure, the elephant can still
breathe an astounding 310 liters of air every minute. The internal structure of the elephant’s
lungs are larger than smaller species and allow the alveoli to situate in such a way that the sheer
weight of the animal and gravity do not offer any resistance to proper breathing and oxygenation.
Like all mammals, airflow come in through the mouth and the nostril to the nares and down the
trachea into the lungs; then the opposite occurs for respiration. The speciation of the trunk
allows it not only breathe for the animal, but it can also hold liquids and food with in it without
interruption of respiration (“Elephant respiratory system, n.d.).
Even though the trunk of an elephant can used to hold liquids or aid in eating, the
elephant cannot drink or eat directly through it. The elephant can only use its trunk to squirt
liquid and put food into its mouth where it can be masticated and swallowed. When comparing
digestive systems to other mammals, the elephant has a system much like that of a horse or zebra
allowing it to be known as a non-ruminant mega herbivore. Through the elephant’s life time,
they can have six sets of molars. At any one time, all that is possessed for mastication are just
four large teeth: two in the upper jaw and two in the lower. The movement of the elephant’s
teeth is unique in in that they do not completely shed their milk teeth; rather, the anterior teeth
are the old, worn teeth while the posterior molars are the new teeth. Unfortunately, because of
this unique way of tooth movement and the elephant’s fibrous diet, many elephants’ last set of
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teeth wear out around age sixty, and if they are not able to adjust their diet, they starve to death.
Interestingly, the animals’ well known large tusks are actually lateral incisors that grow
continuously throughout the animal’s lifetime at an average rate of 15 to 20 centimeters per year.
Instead for mastication, the tusks are used for fighting, digging, carrying, and debarking trees
(“Elephant anatomy and,” n.d.). Sadly, because of their size and unique composition, elephant
tusks have been the target of poachers and ivory dealers for centuries, in which the animal is
often killed for goods.
After the food is chewed by the animal, it passes through the esophagus and down into
the stomach. The elephant’s digestive system functions much like any other mammal with the
main difference being the massive size of each organ respectively. Due to this massive size, the
maximum capacity of their stomach is around 76 liters, and due to their unique diet, they are
prolific saliva producers in order to process the mass of fibrous nutrients into the stomach. Their
stomachs are actually cylindrical in shape with the middle of the organ remain more glandular in
shape. From the stomach the food is processed into the intestines, which can actually reach a
length of 19 meters. Because the animal is an herbivore, the intestine is where most of the
digestion actually will take places, where bacteria in the sacks of the caecum are used to ferment
and break down the hard to digest cellulose and aid in the absorption of most of the water and
nutrients. Because of the animal’s diet, the elephant only can benefit from around 40 percent of
its entire intake turning the rest into feces and urine, ultimately requiring the animal to forage
and eat 24 hours a day and consume up to 240 kilograms of food relative to its size (“Elephant
anatomy and,” n.d.).
Interestingly enough, the elephant’s urinary system functions much like ours; the main
differences lie within the unique size and shapes of the organs. The kidneys in the elephant
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contain eight lobes, and the left kidney is more caudal than the right. Much of the animal’s other
urinary tract functions are similar to other mammals, but the elephant can release up to 50 liters
of urine daily depending on their intake. Their urine is usually clear to straw like in color and
almost always alkaline in pH. An elephant’s urine contains uric acid with about two grams of
the animal’s urine containing minerals and organic solids. Additionally, the elephant typically
has low serum blood urea nitrogen values. Like any other mammal, the elephant is susceptible to
urinary tract diseases and conditions that may even compromise the animal’s reproductive
system in the process (Murray & Fowler, 20116).
Unlike most mammals, the testicles of the elephant are located within the body close to
the kidneys. The male reproductive system is about two meters long, and the males usually
become sexually mature around 10 to 15 years of age. Periodically, males go through a period of
high testosterone production musth. This results in high aggression and is recognized by the
presence of fluid behind the elephant’s eyes and patches of urine on the elephant’s skin. Male
elephants actually test a female’s ability for reproduction by sampling the female’s urine on the
roof of their mouth. Female elephants typically can reproduce beginning around 12 to 15 years of
age, and if the cow becomes pregnant, the gestation period is about 21 to 23 months with at least
a five year period between births to raise the youths. Calves are born fully functional and ready
to walk once the animal’s nervous systems recover from the initial shock of birth (“Elephant
reproduction,” 2009).
Like within most mammals, the brain, spinal cord, and peripheral nerves make up the
animal’s central nervous system. Most are aware that the elephant is a very intelligent animal,
and the brain of the elephant is the largest among all other land animals on earth; yet,
interestingly, their brain is actually quite small in reference to its massive size. With male
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elephants, the brain usually weights about 4.2 to 4.5 kilograms and about 3.6 to 4.2 kilograms
within the average female. Yet, there has never been any noticeable difference between males
and females of any elephant species recorded to this date. However, this may be to the fact that
much of the current data in the field of research is rather old, dating back to the 19th century in
fact, and information is usually difficult to trace (Bull, 2001). This is why very recently
scientists are beginning to study this topic again for further understanding. It is now known that
the elephant is in fact one of the most intelligent animals; it is mainly due to a highly developed
and complex pattern of gyri and sulci. The main differences associated with the elephant spinal
cord are two enlargements: one cervical and one lumbar. These enlargements are specifically
there because they are rich in nerve cells; this is something that is extremely important for the
animal’s ability to power and drive their massive limbs (“Elephant anatomy and,” n.d.).
The peripheral nervous system gives elephants a moderate sense of sight, but a very well
developed sense of hearing, smell, and touch. Elephants have very good hearing and can detect
sounds as low as 14 to 16 hertz and up to 12,000 hertz. It has been believed, that the common
elephant can hear the lower frequency sounds of other elephants from up to 0.9 miles away thanks to the animal’s uniquely large ears. The olfactory senses of the elephant are just as
powerful. They can smell sources from up to 12 miles away, and if that is not enough, elephants
have a special sensory organ known as the Jacobson’s organ located on the upper palate. This
organ is attached to the mouth through the nasal passage way and acts as a special chemical
receptor site for additional sensory information. Even the animal’s sense of touch is highly
developed, allowing it to detect pressures as shallow as 0.1 inches into its body. However, the
most interesting part of the animal’s sensory system is its ability to detect minute seismic
vibrations through special sensing membranes called pacinian corpuscles. These corpuscles are
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made of layers of connective tissue under the animal’s skill that can be compared to the layers of
an onion. These layers contain a slimy gel between them that, when a vibration is felt, causes a
deformity within the corpuscle that stimulates the nerves directly. Amazingly, it is thought that
elephants survived the Asian tsunami of 2004 because this specialization of their sense of touch
gave them an advanced warning of danger because they were able to feel the seismic
disturbances well ahead of time (“Elephants senses,” n.d.).
Due to the massive size of the elephant, it’s equally massive limbs and body systems
mean that it requires a heart and circulatory system to keep the animal alive. The heart of the
elephant usually eights anywhere between 12 to 21 kilograms and has an apple like shape
containing double ventricular apices. Large sinuses within the heart are able to sustain the high
blood pressure needed to maintain circulation and aid in the cardiac contraction to prevent any
damage that may be done to the peripheral blood vessels. The sinuses are found on both sides of
the temporal area along the sternum, trachea, axillae, and inguinal areas. Interestingly, due to the
sheer weight of the animal, the vasculature of the vessels are stronger and thicker walled then
that which can be found in almost any other mammal. Blood composition within the elephant is
similar to any other mammal, with the exception of the blood cells are actually larger to carry
enough oxygen to keep the animal alive (“Elephant anatomy and,” n.d.).
Lastly, the elephant’s integumentary system acts just like that of any other mammals.
However, skin thickness is not equal throughout the body. The skin on the elephant can be up to
2.5 to 3.5 centimeters thick on its back and buttocks and only 1.8 millimeters thick on areas such
as the ear, around the mouth, and around the animal’s anus. Again, like most mammals, the
elephant’s skin is comprised of two layers: the dermis and epidermis and still contains hair
follicles and glands connected to a very rich nerve supply. Skin colors can be brown to reddish,
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like in African elephants and grey in Asian elephants. Elephants are not very hairy animals;
adults have less hair than calves and African elephants actually have less hair than Asian
elephants. The hairs concentrate around the end of the tail and around the mouth, ears, chin, and
eyes for extra protection. The elephant actually lacks sweat glands over the majority of its body:
therefore, they cannot be used for regulation of body temperature. Their main means of
thermoregulation are utilized by the massive surface area of the ears, which is used to radiate
heat outwards away from the animal, which is why it is common to see an elephant constantly
flapping its ears as a means to increase the heat radiation. An altered sebaceous gland known as
the musth is part of this system. The gland is located between the eye and ear of the animal and
is a very important gland for the animal’s reproductive system as mentioned earlier (“Elephants
anatomy and,” n.d.).
As one can clearly see, the elephant is a very unique mammal within the animal kingdom. The
similarities between the animal and the other aforementioned species are often very subtle
compared to the obvious differences noted. Yet, even though the elephant is a massive, mostly
peaceful, and very intelligent animal, it is still very specialized and highly evolved to live within
its environment. In order to keep this animal as one of the most unique on earth, people strive
every day to further understand, help maintain and conserve the animal’s habitat, and ensure the
animal’s safety. Although the elephant populations still live in captivity to this day, go out,
explore, and learn about this interesting animal. Ensure that future generations are able to see
this amazing animal thrive and remain the way that they are meant to be.
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References
Bull, B. An overview of the central nervous system of the elephant through a critical appraisal of
the literature published in the XIX and XX centuries. Chicago: Cozzi Spagnoli, Bruno
Zooi.
Elephant anatomy and physiology. (n.d.). ANCF. Retrieved from
http://www.asiannature.org/know-elephant/elephant-anatomy-and-physiology
Elephants are amazing! (n.d.). Association of Zoos and Aquariums Elephant Taxon Advisory
Group & Species Survival Plan. Retrieved form
http://elephanttag.org/General/general_home.html
Elephant reproduction. (2010, June). Association of Zoos and Aquariums Elephant Taxon
Advisory Group & Species Survival Plan. Retrieved from
http://elephanttag.org/General/general_elephant_reproduction.html
Elephant respiratory system. (n.d.) Elephants forever. Retrieved from
http://www.elephantsforever.co.za/elephants-respiratory-system.html
Elephants move like 4x4s: Scientists. (2010, March 30). Phys.org. Retrieved from
http://phys.org/news189160019.html
Elephants senses. (n.d.). SeaWorld Parks and Entertainment. Retrieved from
http://seaworld.org/animal-info/animal-infobooks/elephants/senses/
Murray, E., & Fowler, S. K. (2006). Chapter 29 urinary system. In S. K. Murray, & E. Fowler,
Biology, medicine, and surgery of elephants (p. 398). Ames, IA: Blackwell Publishing.