Somali Giraffe

Reticulated Giraffe
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Family: Giraffidae
Genus: Giraffa
Species: G. camelopardalis
Subspecies: G. c. reticulata
Trinomial name
Giraffa camelopardalis reticulata
De Winton, 1899
Range map in red

The Somali Giraffe, or more commonly known as Reticulated Giraffe (Giraffa camelopardalis reticulata), is a subspecies of giraffe native to Somalia, northern Kenya and southern Ethiopia. Reticulated giraffes can interbreed with other giraffe subspecies in captivity or if they come into contact with populations of other subspecies in the wild.

The reticulated giraffe is among the most well-known of the nine giraffe subspecies, and together with the Rothschild giraffe it is by far the giraffe most commonly seen in zoos.[1] Its coat consists of large, polygonal liver-colored spots outlined by a network of bright white lines. The blocks may sometimes appear deep red and may also cover the legs. The extraordinary height of giraffes is attributed to a ritual known as "necking" where two males fight for reproduction rights by slamming their necks into one another. The giraffes with the tallest and strongest necks are victorious and allowed to reproduce, thus passing these genes on to future generations.[2]

Contents

Habitat

Giraffe are found in Africa on game preserves and wildlife parks. They are hardly found in the wild due to poaching and over development by humans. Giraffe are typically found in all parts of Africa, except North Africa. The vegetation is too sparse and the land is too heavily populated to accommodate giraffe.[3] Giraffe prefer the open savannas, but do sometimes venture into wooded areas. They can easily camouflage by hiding between trees.

Diet

Reticulated giraffe are herbivorous, since they eat mostly plants, although giraffe have been seen eating the carcass of an antelope.[3] A giraffe’s favorite snack is the acacia bushes and trees that frequent the African landscape. While these leaves are preferred, a giraffe will munch on many other kinds of vegetation. Giraffe food preferences change according to seasons: in the dry season, they seem to be fine with pine like needles.[3] Giraffe feed by browsing, which typically means they eat continuously throughout the day. A male is able to eat 75 pounds of food in a single day.[4] Giraffe use their sense of smell to locate the leaves they want. They ingest everything on the branch when eating, including insects, bark, and thorns. The giraffe uses its massive tongue (up to eighteen inches long) to scrape off the leaf.[3] Giraffe have very tough lips to guard against scratching. While the acacia tree is their favorite, giraffe have also been known to eat mareola berries and other fruits.[4] Giraffe have become intoxicated off the mareola berry, since it ferments in their stomach.[4] Reticulated giraffe are ruminants, just like cows and other ungulates. As explained in Stattler’s Giraffes, The Sentinels of the Savannah, the giraffe stomach has four parts, with food passing through the first and water going directly to the second. The first stomach partially digests the twigs, leaves, and whatever else the giraffe has ingested whole. During the day, when the animal is not feeding, parts of this fermented mixture are brought back up from the stomach in hard lumps. Giraffe chew on these lumps, called cud, throughout the day, helping to further break the food down. Once they are done chewing on the piece of cud, it is sent to the third stomach, and finally the fourth stomach to be digested fully.[4]

Giraffe are very good at conserving water in the hot African climate. Giraffe are able to conserve and maintain their body temperature in part because of their shape- their long thin legs allow heat to release quickly.[4] The leaves they eat are actually a good source of water, and can allow them to go days without a drink.[5] Giraffe have a difficult time lowering their massive heads to the ground to drink, and this also leaves them vulnerable to predators. They are able to bend down by spreading their front legs and stretching their neck down.

Necking

The commonly accepted reason that giraffes have such long necks was proposed by Charles Darwin in 1871. Darwin got his idea from many African locals, who said the giraffe evolved its long neck to reach the tops of the trees, where the best leaves reside.[2] This presents a possible advantage of giraffe being the only one able to feed on prime leaves.

However, this theory has been challenged by Simmons. In his research, Simmons finds that giraffes feed mostly at shoulder level, not reaching the tops of trees at all. They only reach for the top of the tree during the rainy season. He found that in all the giraffes studied, only those in South Africa fed on leaves that were out of the reach of other animals. This presents a problem to the theory that long necks serve as an advantage in feeding.

An alternate theory has to do with mating rituals and sexual selection. Giraffes often find mates through a technique known as “necking”. The males stand next to each other and swing their necks wildly at the other. Whichever giraffe uses his neck and head most effectively and remains standing the longest is declared the winner and is allowed to mate with the female. Robert Simmons’s hypothesis is that giraffes with the longest and strongest necks would be the most likely to win the “necking” contest.[2]

Reproduction

Once pregnant, a female giraffe has a gestation period of about 15 months and usually only has one young at a time, but can have up to eight in her lifetime.[5] Females return to the same spot each year to give birth to their young.[5] Giraffe have babies at all times during the year, but most of the births occur during the dry season.[6] When born, baby giraffes fall seven feet to the ground, since mother giraffes birth standing up.[7] Giraffe calves can weigh up to 200 pounds when they are born, and stand as tall as 6 feet.[7] Baby giraffe can stand up less than half an hour after being born, and are able to feed from mother’s milk. Baby giraffe will continue to feed from the milk until they are about a year old.[7] Giraffe are the only animals born with horns, although the horns on a new born giraffe are only a few inches long.[5] Calves can grow 9 inches during the first month, and continue to grow at an enormous rate during the first year.[3] After that, growth slows to less than an inch per year. Giraffe are very herd oriented animals, and will even entrust the care of their young to the crowd.[6] Females begin to breed at about 4 years, and males at about 10 years.[7]

Predators and threats

Due to their formidable size and ability to spot danger, giraffe have very few predators. Unless a giraffe is a newborn, sleeping, or drinking, they are not targeted as food. Giraffe have been killed by lions and crocodiles.[3] Humans are one very real threat to giraffe, although efforts are being made to help conserve them. Giraffe are killed by poachers for their hair and skin. Giraffe have very thick, sturdy hair that is highly sought after for bracelets and rope. Some villages in Sudan legally serve giraffe meat.[7] Currently, there are about 100,000 giraffe roaming Africa, although some subspecies are almost completely gone, with fewer than 100 individuals.[8] Giraffe have to deal with the Tsetse fly, which land on them and suck blood. Tsetse flies are also carriers of sleeping sickness, a dangerous disease to humans.[7] Giraffe can use their powerful tails to swat the flies and get some relief from the pest. Giraffe have a symbiotic relationship with a few types of birds, most notably the oxpecker. These small birds perch on the backs of giraffe, and alert them to possible predators. Oxpeckers also eat mites and dirt off the giraffe, keeping them clean.[3] However, the oxpecker can irritate other wounds by pecking at them, too. Epidemics have also affected giraffe. The worst one, according to scientist Anne Dagg, was rinderpest, which killed hundreds of giraffe in the 1880s. The epidemic continues to arise in small bursts; one in the 1960s wiped out half of the giraffe population of Kenya.[3]

References

  1. ^ ISIS (2010). Giraffa. Version 1 October 2010
  2. ^ a b c Simmons, Robert E., Scheepers, Lee. (1996). Winning by a neck: sexual selection in the evolution of giraffe. The American Naturalist, 148(5). 771-86. Retrieved April 15, 2009, from JSTOR database.
  3. ^ a b c d e f g h Dagg, Anne. (1976). The Giraffe: its biology, behavior, and ecology. New York: Van Nostrand Reinhold Company.
  4. ^ a b c d e Sattler, Helen. (1989). Giraffes: the sentinels of the savannas. New York: Lothrop, Lee & Shepard Books.
  5. ^ a b c d Markert, Jenny. (2001). Giraffes. Chanhassen, MN: The Child’s World, Inc.
  6. ^ a b Sinclair, A.R.E., Simon, A., Mduma, R., and Arcese, Peter. (2000). What determines phenology and synchrony of ungulate breeding in Serengeti? Ecology, 81(8). 2100-2111. Retrieved April 19, 2009, from JSTOR database.
  7. ^ a b c d e f Leach, Michael. (2001). Giraffe. Austin, Texas: Raintree Steck-Vaughn Company.
  8. ^ Raw Story: African giraffes highly endangered: study. (2007) Retrieved from http://rawstory.com/news/afp/African_giraffes_highly_endangered__12222007.html

External links