Download The Stretch of the Giraffe, by Ismenia Castelan - mhs

The Stretch of the Giraffe, by Ismenia Castelan
When people think of a giraffe, the first thing that they might think of is their immensely long
necks, which is an essential adaptation to their survival. Although, have you ever thought about
how those long necks came to be?
The main reason is due to evolution. Evolution has allowed these creatures to evolve from
probably short necks, into long, tall necks. Although, some people might ask themselves; “why
are giraffes the animals with long necks?”, “why not a mouse, or a dog?” Scientists have come
up with several theories about these questions.
Natural Selection
Many scientists have considered Darwin’s theory of
Natural Selection to be the reason for the giraffe’s long
neck. Darwin once mentioned in his book, Origin of
Species, about the giraffe’s evolution and how natural
selection applied to them. He thought giraffes had long
necks in order for their survival to remain steady during
times when there was a lack of food. He thought the long
neck was a feeding adaptation of the giraffe since they
use it to reach leaves and foliage off of tall trees or high
places. Though, some scientists do not believe their long
necks were specifically made for feeding advantages.
They believe their elongated legs help them with reaching high places and their necks are used
for other reasons such as balance when they are running away from predators. A scientist named
Jean-Baptist Lamarck once said, “variations in the environment induce changes in the needs,
habits, and modes of life of living beings.”
Sexual Selection
Other scientists believe the evolution of the giraffe’s long neck is due to Sexual Selection. They
have found that female giraffes tend to be more attracted to males with longer necks. Therefore,
the theory is that the female would mate with the long-necked male and then the male would
pass on his long-necked genes to the offspring. The cycle would then repeat itself again and
again. Scientists believe in this theory as more likely since it would also explain the difference in
the length in necks between the different genders. They believe the neck length of the giraffes
play an important part in their sexual behavior. As biologist Pryor says in his article, “Long
necks are certainly involved in the giraffe’s sexual behaviors: male and female giraffes
commonly practice “necking” behavior during courtship, which involves gently rubbing and
entwining their necks together”(Pryor).
Other Reasons?
There are other theories as to how and why the giraffes have such long
necks. Some believe giraffes have long necks because they would stretch
their necks so much to reach the leaves of the trees that they eventually
became longer and so they passed it on to their offspring. Others believe
the long necks serves as a weapon for male giraffes when they are fighting
for a female, they can use it to beat or strangle their enemy. Other people
believe the reason is for the giraffes to have a better view of their
surroundings and watch for any predators nearby.
The reason for the giraffe’s extended neck still remains a mystery to people and scientists all
over the world. Whatever the reason may be, all we know for sure is that the evolution of the
giraffe’s long neck is an important adaptation to their survival in this world.
Works Cited
Holdrege, Craig. "The Nature Institute - The Giraffe's Short Neck." Nature Institute: Viewing
Nature, Science, and Technology in Context. The Nature Institute, 2003. Web. 19 May
2011.
"How the Giraffe Got Its Long Neck II « Why Evolution Is True." Why Evolution Is True.
Wordpress.com.Web. 18 May 2011.
Pryor, Greg. "Giraffe Necks." From the PENDULUM to the LYNX and the HARE. 2003. Web.
19 May 2011.
evolution.berkeley.edu
ecotravel.co.za