Student assignment. (requirement for course by Peter Kabai)

Charithea Herodotou

GIRAFFES - Why such a long neck? One of the problems evolution theory has not solved. No scientific evidence on this yet BUT

A Giraffe is a non-dangerous mammal with no much attention drawn to its life as to the life of lions, fast leopards and other wild life animals. Human is not their enemy. They are not used for food, not even for folk medicine remedies. They are just admired for their enormous size and natural beauty and mild nature. The only strange thing we find on this animal is its long neck which allows them to

feed on the leaves of high trees

should I actually state that it is the only existing long neck one.

What If Dinosaurous still existed to these recent days?

Reading about the Giraffes I do find their life quite impressive and would love to share my enthusiasm !!!

On a summer trip in 1997 (when I was only 10 years old) I admired Giraffes in their wild environment. On a safari drive on our way to Ngorongoro Crater up north of Tanzania, a group of 6/7 giraffes were sat down on the ground among the papai trees and you could only see their long neck moving from side to side. My question was whether they were boys or girls and the guide said to me mixed. Trying to read as much on these lovely animals I now know that he could have been wrong; those were certainly girls!!!!!! And the one wondering around alone was the Loner Male Giraffe. Intresting! female giraffes live mostly in groups whereas male giraffes are Loners!!!!

CHARACTERISTICS

It belongs to the family Giraffidae order Artiodactyla class Mammalia phylum Chordata kingdom Animalia. It has only one other species the okapi.
There are 9 recognized subspecies differentiated by their coat pattern/colour and geographical distribution. Noted that all 9 subspecies are found in their natural environment all over the African Continent ONLY.

There to be more subspecies but are not recognized because of disagreements between scientists.

ˇ is the tallest of all land-living animal species. Males can be 4.8 to 5.5 metres (16 to 18 feet) tall and weigh 800-930kg. Females are generally slightly shorter 13-16 feet tall (4-4.8m) and weigh less (550-1,180kg).

ˇ Its true! Its long neck has seven neck vertebrae just like human and horse. The difference is that are greatly enlarged. These enlarged bones are called ossicorns. Each one can be over 10 inches (25.4cm long).

**Just a little note but on a figure of bachiosaurus skeleton I counted 12!!

Their forelegs are 10% longer than their hind legs.
Their heart can weigh up to 10 kg and can pump 16 gallons of blood in 1 minute.
Have a stomach with 4 compartments that digests their food. When they arent eating they are chewing their food. After swallowing the leaves the first time a ball of leaves will come back up the throat for more grinding.
When they lower their head to drink water there is a pressure regulation system called rete mirabile which prevents excess blood to flow to the brain. Also by lowering the head blood vessels in lower legs are under great pressure but because giraffe has tight sheath of thick skin over their lower limbs it maintain high extravascular pressure.
Giraffe has the largest eyes of any land mammal.
A giraffes tongue is 18 to 20 inches (46-50cm) long and blueblack colour.
Unbelievable but True; giraffe has the longest tail of any other land mammal? Can be 8 feet (2.4 metres) long
Giraffe sleep standing up

Female and Male interaction (courtship behaviour)

Their behaviour is very casual and indiscriminate; males can mate with as many females as possible. Females seem to have no problem on this.

Mating occurs year round. Female estrus occurs every 2 weeks and lasts around a day.

Males, when they come across a female they perform several behaviors known as flehmen to test her receptiveness, First the male get closer to the female and nudges her rump to induce urination. If the female urinates male scoops up with his mouth and raise his head to taste it. Then if the male determine that female is receptive attempts to court her.

NOTE: urine of estrus female has a distinct taste.

Males choice for its mate is based on age and receptiveness. They show more interest for young females maybe because they have high fertility or less chances to have already been pregnant.

Females choice:- They prefer older and more dominant males. They play hard to get allowing the strongest male to mate in order to have the advantage to get the best genes for her offsprings.

Female giraffes are very independent, and extremely selfish. They obtain their food and other resources and take care of the young ones by themselves. They have great predator defense, since they form and move in groups

Social Interactions (Male-Male, Female-Female interactions)

Licking and nosing between giraffes serve as a bonding and recognition function too.

Adult male giraffe spends most of its time alone. The wild great loners!

Female giraffes are more often found in mixed groups.

Males play dangerously by necking (sparring). They take turns hitting one another with their massive necks and heads and they are doing this for up to 1-2 hours a day. The injuries are un-avoidable.

Scientists studying this behavior came to the conclusion that this is what they called sexuo-social bonding mechanism. Male giraffes are doing this to build a dominance hierarchy for obtaining female mates. There are different views on this phenomenon and disagreements but a sure thing is that it has something to do with dominance hierarchy among the population of male giraffes.

**Amazing to note that in case of a fight between male giraffes of different sizes the fight always starts from the smaller giraffe.

** Rarely to see a fight between females.

Young Giraffes are called calves for the first 18 months of their lives and they stay close to their mother for nursing and parental care. Thereafter are called sub-adults until they are 5 years old when they reach sexual maturity and considered as adults.

Giraffes defend themselves by a). Kicking with great force and b). Producing a hormone that makes their skin smell bad and repel anyone coming close to them

Hypothesis & Evolutionary Perspectives

Going through my research I have found something very interesting and I would like to share it. Whether the neck is long or short it depends on our perspective and well yes thats true maybe the explanation is too logical or too simple thats why they keep searching and have disagreements.

Main point is that when we see a giraffe we can recognize it. The long neck is a great advantage. It is a protection weapon in males, allows feeding from high trees, gives the advantage to see from high fields as well as for combat and competition for greater access to estrous females.

Hypothesis have been made from Darwins theory which came in contradiction with Lamarks principle. Lamarcks wrote that variations in the environment can cause some changes if its needed to habits and way of life of living beings and these changes are due to skeleton structure, development in organs and etc. After sixty years Darwin came with Origin of species and natural selection that every species consist of individual that show considerable variation. Lamark argued for the inheritance of acquired characteristics. It could actually be true that acquired traits are not genetic and therefore not passed on to offsprings.

A research was carried in Mikumi National Park Tanzania to observe behaviour of sexual segregation by Massai giraffes at a.) habitats and b.) landscape

The suggestion of sexual dimorphism body size hypothesis (females have shorter neck than the male giraffes) provides an unusual explanation for the observed feeding height selection patterns whereas a reproductive strategy hypothesis explain sex-differences in habitat selection patterns within landscapes. Also on this scientists made this hypothesis and came to the conclusion of evolution,

WHAT IF Brachiosaurus still existed ? This was an enormous long-necked, plant-eating dinosaur that lived during the Jurassic period, 156-145 million years ago. Fossils have been found in North America and Africa

Then Giraffes would not then have been the only long existing long neck animal!!!! She would have a competition

What we can say this is evolution

DONT JUST BELIEVE SEARCH AND IMPROVE!!!

References:

African journal of ecology article March 1999 vol 37 page 93

http://www.zoo.org/educate/fact_sheets/savana/giraffe.htm

http://natureinstitute.org/pub/ic/ic10/giraffe.htm

http://www1.pacific.edu/˜e-buhals/GIRAFFES2.htm

http://bill.srnr.arizona.edu/classes/182/Giraffe/winning ByANeck.pdf

http://en.wikipedia.org/wiki/Girrafidae

http://www.sandiegozoo.org/animalbytes/t-giraffe.html

http://animaldiversity.ummz.umich.edu/site/accounts/information/Giraffa_camelopardalis.html

http://www.bio.davidson.edu/people/vecase/Behavior/Spring2004/breedlove/matingsystem.html

http://www.nature-wildlife.com/bones0.html

http://www.enchantedlearning.com/subjects/dinosaurs/dinotemplates/Brachioskel.shtml

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Student essays		Kabai Péter
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Charithea Herodotou GIRAFFES - Why such a long neck? One of the problems evolution theory has not solved. No scientific evidence on this yet BUT A Giraffe is a non-dangerous mammal with no much attention drawn to its life as to the life of lions, fast leopards and other wild life animals. Human is not their enemy. They are not used for food, not even for folk medicine remedies. They are just admired for their enormous size and natural beauty and mild nature. The only strange thing we find on this animal is its long neck which allows them to feed on the leaves of high trees Or should I actually state that it is the only existing long neck one. What If Dinosaurous still existed to these recent days? Reading about the Giraffes I do find their life quite impressive and would love to share my enthusiasm !!! On a summer trip in 1997 (when I was only 10 years old) I admired Giraffes in their wild environment. On a safari drive on our way to Ngorongoro Crater up north of Tanzania, a group of 6/7 giraffes were sat down on the ground among the papai trees and you could only see their long neck moving from side to side. My question was whether they were boys or girls and the guide said to me mixed. Trying to read as much on these lovely animals I now know that he could have been wrong; those were certainly girls!!!!!! And the one wondering around alone was the Loner Male Giraffe. Intresting! female giraffes live mostly in groups whereas male giraffes are Loners!!!! CHARACTERISTICS It belongs to the family Giraffidae order Artiodactyla class Mammalia phylum Chordata kingdom Animalia. It has only one other species the okapi. There are 9 recognized subspecies differentiated by their coat pattern/colour and geographical distribution. Noted that all 9 subspecies are found in their natural environment all over the African Continent ONLY. There to be more subspecies but are not recognized because of disagreements between scientists. ˇ is the tallest of all land-living animal species. Males can be 4.8 to 5.5 metres (16 to 18 feet) tall and weigh 800-930kg. Females are generally slightly shorter 13-16 feet tall (4-4.8m) and weigh less (550-1,180kg). ˇ Its true! Its long neck has seven neck vertebrae just like human and horse. The difference is that are greatly enlarged. These enlarged bones are called ossicorns. Each one can be over 10 inches (25.4cm long). Just a little note but on a figure of bachiosaurus skeleton I counted 12!! Their forelegs are 10% longer than their hind legs. Their heart can weigh up to 10 kg and can pump 16 gallons of blood in 1 minute. Have a stomach with 4 compartments that digests their food. When they arent eating they are chewing their food. After swallowing the leaves the first time a ball of leaves will come back up the throat for more grinding. When they lower their head to drink water there is a pressure regulation system called rete mirabile which prevents excess blood to flow to the brain. Also by lowering the head blood vessels in lower legs are under great pressure but because giraffe has tight sheath of thick skin over their lower limbs it maintain high extravascular pressure. Giraffe has the largest eyes of any land mammal. A giraffes tongue is 18 to 20 inches (46-50cm) long and blueblack colour. Unbelievable but True; giraffe has the longest tail of any other land mammal? Can be 8 feet (2.4 metres) long Giraffe sleep standing up Female and Male interaction (courtship behaviour) Their behaviour is very casual and indiscriminate; males can mate with as many females as possible. Females seem to have no problem on this. Mating occurs year round. Female estrus occurs every 2 weeks and lasts around a day. Males, when they come across a female they perform several behaviors known as flehmen to test her receptiveness, First the male get closer to the female and nudges her rump to induce urination. If the female urinates male scoops up with his mouth and raise his head to taste it. Then if the male determine that female is receptive attempts to court her. NOTE: urine of estrus female has a distinct taste. Males choice for its mate is based on age and receptiveness. They show more interest for young females maybe because they have high fertility or less chances to have already been pregnant. Females choice:- They prefer older and more dominant males. They play hard to get allowing the strongest male to mate in order to have the advantage to get the best genes for her offsprings. Female giraffes are very independent, and extremely selfish. They obtain their food and other resources and take care of the young ones by themselves. They have great predator defense, since they form and move in groups Social Interactions (Male-Male, Female-Female interactions) Licking and nosing between giraffes serve as a bonding and recognition function too. Adult male giraffe spends most of its time alone. The wild great loners! Female giraffes are more often found in mixed groups. Males play dangerously by necking (sparring). They take turns hitting one another with their massive necks and heads and they are doing this for up to 1-2 hours a day. The injuries are un-avoidable. Scientists studying this behavior came to the conclusion that this is what they called sexuo-social bonding mechanism. Male giraffes are doing this to build a dominance hierarchy for obtaining female mates. There are different views on this phenomenon and disagreements but a sure thing is that it has something to do with dominance hierarchy among the population of male giraffes. Amazing to note that in case of a fight between male giraffes of different sizes the fight always starts from the smaller giraffe. Rarely to see a fight between females. Young Giraffes are called calves for the first 18 months of their lives and they stay close to their mother for nursing and parental care. Thereafter are called sub-adults until they are 5 years old when they reach sexual maturity and considered as adults. Giraffes defend themselves by a). Kicking with great force and b). Producing a hormone that makes their skin smell bad and repel anyone coming close to them Hypothesis & Evolutionary Perspectives Going through my research I have found something very interesting and I would like to share it. Whether the neck is long or short it depends on our perspective and well yes thats true maybe the explanation is too logical or too simple thats why they keep searching and have disagreements. Main point is that when we see a giraffe we can recognize it. The long neck is a great advantage. It is a protection weapon in males, allows feeding from high trees, gives the advantage to see from high fields as well as for combat and competition for greater access to estrous females. Hypothesis have been made from Darwins theory which came in contradiction with Lamarks principle. Lamarcks wrote that variations in the environment can cause some changes if its needed to habits and way of life of living beings and these changes are due to skeleton structure, development in organs and etc. After sixty years Darwin came with Origin of species and natural selection that every species consist of individual that show considerable variation. Lamark argued for the inheritance of acquired characteristics. It could actually be true that acquired traits are not genetic and therefore not passed on to offsprings. A research was carried in Mikumi National Park Tanzania to observe behaviour of sexual segregation by Massai giraffes at a.) habitats and b.) landscape The suggestion of sexual dimorphism body size hypothesis (females have shorter neck than the male giraffes) provides an unusual explanation for the observed feeding height selection patterns whereas a reproductive strategy hypothesis explain sex-differences in habitat selection patterns within landscapes. Also on this scientists made this hypothesis and came to the conclusion of evolution, WHAT IF Brachiosaurus still existed ? This was an enormous long-necked, plant-eating dinosaur that lived during the Jurassic period, 156-145 million years ago. Fossils have been found in North America and Africa Then Giraffes would not then have been the only long existing long neck animal!!!! She would have a competition What we can say this is evolution DONT JUST BELIEVE SEARCH AND IMPROVE!!! References: African journal of ecology article March 1999 vol 37 page 93 http://www.zoo.org/educate/fact_sheets/savana/giraffe.htm http://natureinstitute.org/pub/ic/ic10/giraffe.htm http://www1.pacific.edu/˜e-buhals/GIRAFFES2.htm http://bill.srnr.arizona.edu/classes/182/Giraffe/winning ByANeck.pdf http://en.wikipedia.org/wiki/Girrafidae http://www.sandiegozoo.org/animalbytes/t-giraffe.html http://animaldiversity.ummz.umich.edu/site/accounts/information/Giraffa_camelopardalis.html http://www.bio.davidson.edu/people/vecase/Behavior/Spring2004/breedlove/matingsystem.html http://www.nature-wildlife.com/bones0.html** http://www.enchantedlearning.com/subjects/dinosaurs/dinotemplates/Brachioskel.shtml

Notes (if any) by Peter Kabai: