Our Zoo Visit

Wrapping Up Our Adventures With Giraffes

To finish off our blog on giraffes we visited the giraffe exhibit at the San Diego Zoo.  We had a great time taking pictures and observing these beautiful animals! 

The giraffe in the background of the two above photos is one of the baby giraffes currently at the zoo.  She is only a year old and look how tall she is!

Our fun fact of the week came from one of the workers at the zoo.  She said that people always wonder why don't the giraffes don't just step over the short wall that is keeping them in? The reason for this is because on the other side of the wall there is a 3 foot deep moat.  Surprisingly giraffes don't like to step down more than 6 inches and because they would need to step down into this 3 foot deep moat to cross the wall makes the task seem to risky so they don't even attempt to escape.

At the zoo the giraffes eat from tall tree like structures and also from bins that contain their favorite food...acacia trees!

The picture above is of the only male giraffe at the zoo.  His name is Silver.  If you look closely at his coat pattern you can see that he is a Masai giraffe based on the distinct color and pattern.

And this is us say so long to our giraffe friends at the zoo!!  Thank you everyone for reading our blog.  We hope you enjoyed learning about giraffes just as much as we did!

Scholarly Journal Article

Grazing Behavior of the Giraffe in Hwange National Park, Zimbabwe

As mentioned in a previous post, acacia leaves make up a majority of a giraffe’s diet. Therefore, giraffes are typically classified solely as browsers. “Browsing” is foraging behavior that occurs when a giraffe stands upright, like when eating leaves from a tree (Seeber 248).  However, studies show that giraffes sometimes feed on grass and herbs at ground level, which requires them to assume the ‘drinking position’ where their front legs are spread apart so their heads can reach the ground. Peter A. Seeber and his team of researchers observed giraffe feeding behavior (for a total of 188 hours) from March to May 2011 in Hwange National Park, located in Zimbabwe (247). The team investigated how often grazing is part of giraffes’ feeding behavior, and recorded the number of grazing events observed as well as the duration of the grazing behavior.

Giraffe in Hwange National Park, Zimbabwe

Thirty-one instances of grazing occurred for a total of 174 minutes of grazing, which made up 1.5% of the total observation time (248). Interestingly, giraffes that did graze were almost always in groups, perhaps because the ‘drinking position’ makes giraffes vulnerable to predators. Seeber’s research illustrates that although not a primary activity, grazing does occur in a “nutrient-poor environment” like the Hwange National Park (247). Upon reviewing their results, the researchers concluded, “the function of feeding on herbs during the dry season is not principally to supplement protein/energy intake, but rather to access other nutritional factors not currently present in sufficient amounts in browse… because the herb layer sometimes has more available micronutrients than browse” (249). Further research about the micronutrient content in plants would supplement the research conducted at Hwange National Park.

Giraffe grazing in 'drinking position'

Work's Cited

Seeber, Peter A., Honestly T. Ndlovu, Patrick Duncan, and Andre Ganswindt. "Grazing Behaviour of the Giraffe in Hwange

      National Park, Zimbabwe."  African Journal of Ecology 50.2 (2012): 247-50. Wiley Online Library. Web. 25 Apr. 2012. 

     <http://0-onlinelibrary.wiley.com.sally.sandiego.edu/doi/10.1111/j.13652028.2011.01314.x/abstract;jsessionid=      

     8F1D66A9F273D7BA85E8F2E8453218CC.d03t03>.

A Giraffe's Tongue

Lick It All Up!

One distinct feature of giraffes is their tongues.  Their tongues are on average 18-24 inches in length, dark in color, and extremely tough.  These characteristics are what make the giraffe’s tongue advantageous to their eating habits.  Giraffes usually feed on Acacia trees, which have long thorns that can potentially be dangerous to animals trying to feed on them.  But not for giraffes! Because their tongues are so long they can reach the Acacia leaves without getting poked in the face.  The toughness of their tongues allows them to eat the leaves without getting cuts in their mouth.  The dark color of their tongues is also important because it prevents it from getting sunburned during feeding times.  The characteristics of a giraffes tongue are extremely important for their survival.

Fun Fact of the Week!: A giraffe eats hundreds of pounds of leaves each week and must travel miles to find enough food to fuel it’s body.

Works Cited

"Giraffe." National Geographic. Web. 01 May 2012. <http://animals.nationalgeographic.com/animals/mammals/giraffe/>.

"Mammals: Giraffe." San Diego Zoo's Animal Bytes: Giraffe. Web. 01 May 2012. <http://www.sandiegozoo.org/animalbytes/t-giraffe.html>.

The Stomach of a Giraffe

Chew On This!

Giraffes have a diet high in plant material, which is hard to breakdown.  Because of this, giraffes have a special four-chamber stomach that allows them to breakdown the tough plant material and allow them to obtain the nutrients from it.  The four-chambered stomach has four compartments: the rumen, reticulum, omasum and abomasum.

The first two chambers, the rumen and the reticulum, mix the chewed up plant material with saliva, which is then separated into solid and liquid waste.  The solid waste forms a cud that is regurgitated and then further broken down by the giraffe from chewing. The job of the omasum is to absorb water and other nutrients into the blood stream that were not absorbed in the rumen or reticulum. Once the food has been chewed up again and further broken down by saliva in the mouth, it then moves to the true stomach: the abomasum.  The abomasums breaks down the remaining food material in the same way that our stomach breaks down our food as humans.  From here, giraffe’s food is digested in the same way as ours by moving through the small and large intestine where nutrients are further absorbed.  Although the process of a four-chambered stomach is complex, it is essential for a giraffe to obtain all of the possible nutrients out of its plant-based diet.  The workings of a four-chambered stomach allow the giraffe to do this in the best way possible.

Fun Fact of the Week!: A giraffe only sleeps for 1-12 minutes at a time and usually gets about 30 minutes total in one day!

Bowen, R. "Digestive Anatomy in Ruminants." Arbl.cvmbs.colostate.edu. 23 Nov. 2003. Web. 20 Apr. 2012. <http://www.vivo.colostate.edu/hbooks/pathphys/digestion/herbivores/rumen_anat.html>.

"Mammals: Giraffe." San Diego Zoo's Animal Bytes: Giraffe. Web. 20 Apr. 2012. <http://www.sandiegozoo.org/animalbytes/t-giraffe.html>.

Hard-working Hearts

The Heart of the Matter

Because giraffes are so tall, their hearts must be capable of pumping blood at a high enough pressure to flow up through their necks and into their brains. For this reason, a giraffe’s heart has special adaptations to overcome gravity. A giraffe’s heart can weight up to 25 pounds, and is several inches thick, making it very powerful. Additionally, a giraffe’s heart pumps around 16 gallons of blood per minute!

Giraffe heart

These strong hearts also produce an average blood pressure of 280/180, which is twice the pressure of other large mammals, and more than twice the recommended human blood pressure of 120/80. This high blood pressure is necessary for blood to reach the brain, but could be dangerous when a giraffe lowers its head. For this reason, giraffes have a pressure-regulating system made up of small blood vessels called “rete mirabile,” anti-pooling valves, and reinforced artery walls. This complex system prevents excessive amounts of blood from rushing toward a giraffe’s brain when it lowers its head. The jugular veins in giraffes also have valves that stop blood from flowing backwards into the head when its lowered. 

Interesting fact of the week: Giraffes have heart rates of around 150-170 beats per minute!    

Work's Cited

Bourton, Jody. "Supercharged Heart Pumps Blood Up A Giraffe's Neck." Earth News. BBC, 20 Nov. 2009. Web. 08 Apr. 2012. <http://news.bbc.co.uk/earth/hi/earth_news/newsid_8368000/8368915.stm>.

"Facts About Giraffes." About.com: Animals / Wildlife. Web. 05 Apr. 2012. <http://animals.about.com/od/hoofedmammals/a/tenfactsgiraffes.htm>.

"Giraffes- All You Never Wanted to Know." Squidoo. Web. 08 Apr. 2012. <http://www.squidoo.com/giraffes-all-you-never-wanted-to-know>.

Differences Between Males and Females

Battle of The Sexes

     When you look at a male and female giraffe they are almost impossible to tell apart, except for the fact that males are bigger than females. Here are a couple of distinctions between male and female giraffes that we found interesting:

     Male giraffes weigh about 3,500 pounds and females weigh about 1,800 pounds. Both male and female giraffes range between 16-20 feet tall. The males are usually taller than the females.

     The distinct horns (technically called ossicones) on a giraffe’s head differ between sexes. Female ossicones are usually covered in hair, while the male ossicones are bald on top. To establish dominance, males engage in a behavior called necking. Males will swing their necks and use their horns to hit another male for access to fertile females. With increased impact, the hairs on males’ ossicones wear down. Because females rarely fight, their hairs remain in tact.

           

              Female                                                                       Male

          

     

     Males develop calcium deposits that form bumps on their skulls as they age, which makes it look as though they have additional horns. These calcium deposits help to protect a male's head during a fight.

     Female calves (young giraffes) usually remain close to their original home range once they grow and mature. Male calves are more likely to migrate to other herds away from their home range.

Interesting Fact of the Week: Giraffes are the only animals born with horns. 

Works Cited

"Facts About Giraffes." About.com: Animals / Wildlife. Web. 05 Apr. 2012. <http://animals.about.com/od/hoofedmammals/a/tenfactsgiraffes.htm>.

"Giraffe - The Facts." Nature-Wildlife. Web. 05 Apr. 2012. <http://www.nature-wildlife.com/girextra.htm>.

"How Do You Tell The Difference Between a Male Giraffe and a Female Giraffe?" Blog Spot. Web. 05 Apr. 2012. <http://myfloatleft.blogspot.com/2010/04/how-do-you-tell-difference-between-male.html>.

Coat Patterns

Check Out That Cool Coat!

Giraffes have very distinct coat patterns. Even though there is only one species of giraffes, each of the nine subspecies has different coat patterns based on where they live. The differences between each species’ coat patterns are determined not only by where they live, but also by what they eat.

            A giraffe’s coat pattern acts as a fingerprint in the fact that each one is unique. It distinguishes them from other giraffes in the herd. The differences in coat pattern help young giraffes determine who their mothers are in a large herd because no two giraffes have identical coat patterns.

            A giraffe’s basic coat pattern consists of dark blotches, which are usually brown, chestnut, black, or orange in color. Light hairs that are usually white or cream in color separate these blotches to give the giraffe a distinct coat. Their coat pattern is used as camouflage in their environment, which is why their coat pattern is dependent on where they live. As a giraffe gets older, the color of his or her coat usually darkens, but the pattern stays the same. This is especially true for male giraffes.  

Here is an example of three subspecies of giraffes that all live in Kenya.  They each display unique coat patterns even though they live in similar environments.

The reticulated giraffe (Giraffa camelopardalis reticulata) is distinguished by defined bright patches, which are usually orange or brown in color.  Sharp white or cream lines separate these patches.

The maasai giraffe (Giraffa camelopardalis tippelskirchi) are the darkest subspecies of the giraffes.  Their coat is recognizable by its dark brown jagged edges with a cream or light brown color backgroud.

The Rothschild's giraffe (Giraffa camelopardalis rothschildi) is the most rare of the giraffe subspecies.  Its coat is similar to the maasai giraffe but it is much lighter in appearance.  It is known for the lack of dark color pattern below their knees

Fun fact of the week: Although this rarely occurs, some giraffes are born so dark or light in color that their spots are barely visible! 

Conservation Status

A Tall Order: The Conservation of Giraffes

The International Union for the Conservation of Nature (IUCN) Red List of threatened animals, which evaluates species’ risks of extinction, classifies giraffes as low risk “conservation dependent.” In other words, special conservation efforts are needed for the giraffe species to live on into the future. Though giraffes are not currently endangered, their numbers have declined over the years, with several subspecies becoming increasingly rare. For example there are only 400 Rothschild giraffes, and 445 Uganda giraffes remaining in the wild today! 

Uganda giraffe and newborn  

Sadly, big time hunters travel far distances and pay thousands of dollars to experience hunting a giraffe, a practice known as trophy hunting. In some African countries, this controversial, but legal practice actually helps the community financially and provides food for the people. Although poaching negatively affects the giraffe population, habitat loss and destruction from human construction is the biggest danger to giraffes and other animals in Africa. As the human population grows, giraffe territory is taken over, resulting in giraffe extinction in numerous countries. Luckily, the majority of humans admire this peaceful animal and are awed by their appearance, which means giraffes are never killed by humans out of fear. Additionally, farmers typically do not mind giraffes because they do not eat their crops or compete with their cattle for food.

The future livelihood of this unique animal rests in conservation efforts of giraffe habitats in the wild and on private land. Various organizations, like the Giraffe Conservation Foundation, have made it their missions to work against giraffe extinction in the future.

Interesting fact of the week: Sadly, the Nigerian giraffe has actually become extinct in Nigeria! These giraffes can only be found in Chad. 

Works Cited

"Conservation Status." Born Free: Keep Wildlife in the Wild. Born Free Foundation. Web. 14 Mar. 2012. 

                      <http://www.bornfree.org.uk/ animals/giraffe/conservation/>.

"Giraffe - The Facts." GCF Home. Giraffe Conservation Foundation. Web. 14 Mar. 2012. <http://www.giraffeconservation.org/giraffe_facts.phppgid=51>.

"Giraffe." National Zoo. Web. 14 Mar. 2012. <http://nationalzoo.si.edu/animals/AfricanSavanna/fact-giraffe.cfm>.

"Mammals: Giraffe." San Diego Zoo's Animal Bytes: Giraffe. Web. 14 Mar. 2012. <http://www.sandiegozoo.org/animalbytes/t-giraffe.html>.

Predatory Behavior

Giraffes Kick Butt!

Adult giraffes are very large animals, which makes them basically invulnerable to predators. Lions, leopards, and spotted hyenas will prey on calves when they are still young and weak.  This means the mother giraffes must protect their young until they are strong enough to avoid predators on their own.  Scientist have found that only a quarter of calves survive within a year of being born because they are so weak and defenseless against predators.

One of the only times giraffes are vulnerable to predators is when they are drinking water from a lake or stream.  To drink from something that low to the ground giraffes must spread their legs extremely far apart, which doesn’t allow them to run from, or kick a predator that approaches them. Lions are the main predators of giraffes because they are able to jump on them when they are bent over in this vulnerable position. This is why giraffes must travel in herds to drink from a water source.  Half of the herd will drink while the other half protects them from potential predators.  If predators do approach the herd, giraffes use their powerful legs to kick.  Their kicks are so strong that they can kill a lion instantly if they kick them in the right spot. Also, giraffes have excellent eyesight that allows them to see a predator approaching from a far distance.  If they do see a predator, they are able to run away.  If a predator is able to catch a giraffe, it is very difficult for them to tear the giraffe’s tough, thick skin.

Because giraffes usually inhabit areas of open savannas, they are better able to see an approaching predator as compared to an area, such as a dense forest, where it is hard to see predators that could potentially be hiding and waiting to attack.

Interesting Fact of the Week: The most serious danger to giraffes existence are humans!  Many people hunt them for their skins, even though it is illegal.

Clara. "Giraffe Predators." Document Moved. Web. 06 Mar. 2012. <http://www.asij.ac.jp/elementary/projects/2-eb/zoo/clarak.htm>.

"Giraffe Fact Sheet - National Zoo| FONZ." Welcome to the National Zoo| FONZ Website. 25 Jan. 2010. Web. 06 Mar. 2012. <http://nationalzoo.si.edu/Animals/AfricanSavanna/fact-giraffe.cfm>.

"Giraffes." KIDCYBER. Jan. 2012. Web. 06 Mar. 2012. <http://www.kidcyber.com.au/topics/giraffe.htm>.

Reproductive Behavior

It's All About Giraffes, Baby!          

  

          Reproductive behavior in giraffes is known to occur throughout the year. Females reach maturity at age four while males mature by age seven or eight. Males will migrate to different herds seeking females in estrus, or “in heat,” to mate with. Giraffe reproduction occurs through a multistep process called Flehmen response. This courtship begins when a male approaches a female from behind a nudges her hind leg, causing urination. Once the female begins to urinate, the male will drink the female’s urine to determine if she is in estrus. The male can detect this by the taste of the urine. Once the male has decided the female is in heat, he follows her until she allows him to mount her. Once conception has occurred, the female carries her calf for approximately fifteen months! Females typically give birth to one calf at a time, and remains alone with her calf for about a week to provide protection against predators. After birth, a newborn is between 5’6 and 6’6 feet tall, weighing 104 to 22o pounds!

http://cute-n-tiny.com/cute-animals/mom-and-baby-giraffe/

            Most reproduction in giraffes is polygamous, meaning that a few older males mate with all the fertile females. Usually male giraffes prefer younger females because they are in heat more often than older giraffes. In contrast, females prefer older males as mates. If a dominant male senses that another male might be trying to approach his female during courting (sexual) behavior, he will stare the other down until he leaves. Females allow this behavior to occur because they want to mate with the dominant male for as long as possible, however no long term bonds are formed between male and female. Giraffes will sometimes participate in homosexual behavior, but it mostly occurs with males.

Fun Fact of the Week: Females give birth standing up, so their calves experience a 6 foot drop to the ground! Newborns are not harmed, and are able to stand within a half hour.  

Works Cited

Alex. "30 Strangest Animal Mating Habits." Neatorama. 30 Apr. 2007. Web. 26 Feb. 2012.      

          <http://www.neatorama.com/2007/04/30/30-strangest-animal-mating-habits/>.

"Giraffe Fact Sheet." Welcome to the National Zoo. Web. 26 Feb. 2012. 

          <http://nationalzoo.si.edu/Animals/AfricanSavanna/fact-giraffe.cfm>.

Territorial Behavior

Giraffe Territory: All Are Welcome!

           Giraffes are non-territorial animals.  They are very social and usually travel in packs. The social behavior of giraffes is informal and the individuals in the herd are often changing as they migrate, even within a short time span of 24 hours. Although giraffes travel in packs, there is no coordination to their herd movements. The main reason for their travel is in search of food sources, which leads their direction of migration. Even though they travel in herds, giraffes usually browse for food independently. There is typically no leader of the pack, but males demonstrate their dominance through a behavior called “necking.”

            Necking is a way in which male giraffes test the strength of other males. To do this, both male giraffes swing their necks at each other in an attempt to strike the other with their horns. This can occur at high and low intensities depending on the males participating in the necking. The strength of the blow given from one male giraffe to another depends on the weight of the skull and the strength of the swing.  When a male is on the defense during a necking battle, he will move out of the way of the opponents swing at the last second, and then prepare to attack immediately after.  Those males that win in the display of dominance through necking get their choice of mate and thus, are more likely to reproduce.

            In addition to their non-territorial behavior, giraffes show no preference for others in their herd.  The females in the herd will even look out for other giraffes' calves.

Interesting fact of the week: Giraffes have highly adaptive eyesight.  They are more likely to rely on their eyes, over their sense of smell, to gain awareness of their surroundings.

"The Giraffe - DesertUSA." Desert Biomes by DesertUSA. Web. 15 Feb. 2012. 

          <http://www.desertusa.com/animals/giraffe.html>.

"Giraffe -- Kids' Planet -- Defenders of Wildlife." Defenders of Wildlife - Kids' Planet. Web. 15 Feb. 2012.   

          <http://www.kidsplanet.org/factsheets/giraffe.html>.

"Wildlife: Giraffe." AWF. Web. 15 Feb. 2012. <http://www.awf.org/content/wildlife/detail/giraffe>.

"Giraffes." Animal Corner. Web. 15 Feb. 2012. 

          <http://www.animalcorner.co.uk/wildlife/giraffes/giraffe_about.html>.

Eating Habits and Foraging Behavior

Are you ready to digest more information on giraffes?!

Giraffes are herbivores, meaning they only eat plant-based foods.  More specifically, giraffes are classified as browsers because their diet consists more of trees, and less of grasses.  Because they rely on only leaves to energize their bodies, they must eat large quantities.  Their daily intake can be up to 65 pounds, but they only need 15 pounds to survive.  Giraffes usually live in environments such as the savannas, woodlands, and grasslands that provide sufficient resources for their eating habits.

Acacia trees form the bulk of a giraffes diet. From these trees giraffes are able to eat the leaves and twigs using their strong, long tongues.  The Acacia tree leaves contain a lot of water, which allows them to attain water from resources other than lakes or streams.  The advantage of having high-water content leaves as a food source allows the giraffe to go many days without drinking water.  If they do drink from a water source such as a lake, they can drink up to 12 gallons.

Since both males and females feed from the same type of plants, it is important to not create competition among their own species.  Males often feed on leaves higher on the trees than females, thus reducing competition for food.  Because males feed on higher parts of the tree, their diets contain more fiber while the female’s diet is more nutritious due to eating from lower parts of the tree. For both females and males, eating can take up to 75% of their day, especially during dry season when resources are limited, which requires longer browsing time.

One characteristic that is important to a giraffe’s diet is their unique tongues.  They are about 18 inches long.  Having this long of a tongue allows the giraffe to reach leaves and break branches.  Their tongues are also extremely strong, allowing them to maneuver through and deal with thorny branches. Another important characteristic of a giraffe’s mouth is their thick salvia.  It is produced in large quantities during eating times, allowing them additional break down of food particles.  It also protects the giraffe’s throat from the possibility of being harmed by swallowed thorns.

Additional important foraging behaviors include the way in which they obtain water from lakes and streams.  Because their legs are longer than their necks, they must spread their legs far enough apart to allow their necks to reach the water.  They also have very flexible necks, allowing them to reach high parts of a tree for leaves and also, low level streams for water

After giraffes eat their large amounts of leaves and branches, it is important for them to digest these nutrients properly.  Their ruminant stomach allows them to do this.  After swallowing their food, a giraffe then regurgitates it back up into its mouth for additional grinding and break down of the food.  When giraffes drink water from watering holes, they almost always travel in packs.  This allows them to guard each other from predators while the others drink from the water hole in a vulnerable position (legs extended out). 

Interesting fact of the week: Giraffes have a dark colored tongue, which prevents it from getting sunburnt while reaching for leaves!

"Giraffe - The Facts." GCF. Giraffe Conservation Foundation. Web. 11 Feb. 2012. <http://www.giraffeconservation.org/giraffe_facts.php?pgid=39>. 

"Giraffe Fact Sheet." San Diego Zoo. Global. Web. 11 Feb. 2012. <http://library.sandiegozoo.org/factsheets/giraffe/giraffe.htm>. 

"Giraffe." San Diego Zoo's Animal Bytes. San Diego Zoo. Web. 11 Feb. 2012. <http://www.sandiegozoo.org/animalbytes/t-giraffe.html>.