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>. 

Evolutionary background, close relatives, and taxonomy

Explore new heights and enter the amazing world of giraffes! 

This mammal is part of the Giraffidae family in the genus Giraffa, and is the tallest animal in the world, ranging from sixteen to twenty feet tall. This animal’s species name is G. camelopardalis, but is commonly referred to as giraffe. Giraffes are well known for their extremely long necks, which has sparked interest in the science world from very early on. In fact, in the 19^th century, Jean-Baptiste Lamarck theorized that giraffes’ necks were acquired characteristics. In other words, over generations as giraffes strived to reach higher leaves, their necks naturally grew. However, this theory was eventually disproved, and scientists now believe giraffes’ long necks arose through natural selection. This means that those giraffes that had longer necks had access to more food and were more likely to survive and reproduce.

Around 30 to 50 million years ago, an animal similar to an antelope could be found in the plains of Asia and Europe. This animal is thought to be the original ancestor of the two enduring members of the family Giraffidae; the giraffe and okapi. Around seven million years ago, Giraffa migrated to Africa, and due climate changes Asian giraffes became extinct while the African ones survived. The changes in biome from dense forests to savannas are believed to have lead to the evolution of modern day giraffes beginning eight million years ago. As stated above, the closest living relative to the giraffe is the okapi. This animal has a similar body shape, but a much shorter neck. The giraffe and the okapi both have fur covered horns, specialized teeth and tongues, and a ruminating four-chambered stomach. An advantage of a ruminating stomach is that both animals can chew their food, regurgitate it, and chew it again to allow for more optimal digestion.

Most giraffe species today are found in Southern Africa in savannas, grasslands, and open woodlands. Compared to their shorter relative who lives in dense forests, these areas are optimal for giraffes to move about freely without many obstructions to their height. I hope this gives you a little background information on our amazing animal. There are so many more interesting things to discover about the giraffe, so stay tuned!

Interesting fact of the week: The average height of giraffes’ legs is six feet tall, taller than most humans!    

"Giraffe - The Facts." GCF Home. Giraffe Conservation Foundation. Web. 04 Feb. 2012. <http://www.giraffeconservation.org/giraffe_facts.php?pgid=51>.

"Giraffe." Animals. National Geographic. Web. 04 Feb. 2012. <http://animals.nationalgeographic.com/animals/mammals/giraffe/>.

"Okapi Pictures." Learn Animals - A Library of the Worlds Animals. Web. 04 Feb. 2012. <http://www.learnanimals.com/okapi/pictures.php>.

"San Diego Zoo's Animal Bytes: Giraffe." San Diego Zoo. Web. 04 Feb. 2012. <http://www.sandiegozoo.org/animalbytes/t-giraffe.html>.