WikipediaRead full entry
The reticulated giraffe (Giraffa camelopardalis reticulata), also known as the Somali giraffe, is a subspecies of giraffe native to Somalia, southern Ethiopia, and northern Kenya. 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. Together with the Rothschild giraffe, it is by far the giraffe most commonly seen in zoos. 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.
Giraffe historically occurred widely throughout Africa. Their favoured habitat is savanna, woodlands, seasonal floodplains and rainforest.
Reticulated giraffe are herbivorous and have been recorded to feed on more than 100 species of plants with a staple of Acacia, Commiphora and Terminalia leaves. Giraffe have been seen eating the carcass of an antelope and chewing on dried bones for their calcium content. While leaves are preferred, a giraffe will browse on many other kinds of vegetation, especially in the dry season. Giraffe food preferences change according to seasons: in the dry season, they seem to be fine with pine like needles. 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. 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. 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. 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.
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. The leaves they eat are actually a good source of water, and can allow them to go days without a drink. 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 reach water by spreading their front legs and stretching their neck down.
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. 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.
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. Females return to the same spot each year to give birth to their young. Giraffes have babies at all times during the year, but most of the births occur during the dry season. When born, baby giraffes fall seven feet to the ground, since mother giraffes birth standing up. Giraffe calves can weigh up to 200 pounds when they are born, and stand as tall as 6 feet. 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. Calves can grow 9 inches during the first month, and continue to grow at an enormous rate during the first year. 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. Females begin to breed at about 4 years, and males at about 10 years.
Predators and threats
Due to their formidable size and ability to spot danger, giraffe have very few predators but are regularly preyed upon by lions and less so by crocodiles and spotted hyena. 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. Currently, there are about 100,000 giraffe roaming Africa, although some subspecies are almost completely gone, with fewer than 100 individuals. 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. 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 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. 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 (see 1890s African rinderpest epizootic). The epidemic continues to arise in small bursts; one in the 1960s wiped out half of the giraffe population of Kenya.
- ISIS (2010). Giraffa. Version 1 October 2010
- Simmons, Robert E., Scheepers, Lee (1996). "Winning by a neck: sexual selection in the evolution of giraffe". The American Naturalist 148 (5): 771–86. doi:10.1086/285955. JSTOR 2463405.
- Dagg, Anne. (1976). The Giraffe: its biology, behavior, and ecology. New York: Van Nostrand Reinhold Company ISBN 0442224311.
- Sattler, Helen. (1989). Giraffes: the sentinels of the savannas. New York: Lothrop, Lee & Shepard Books ISBN 068808284X.
- Markert, Jenny. (2001). Giraffes. Chanhassen, MN: The Child’s World, Inc. ISBN 0895657236
- 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. doi:10.1890/0012-9658(2000)081[2100:WDPASO]2.0.CO;2. JSTOR 177099.
- Leach, Michael. (2001). Giraffe. Austin, Texas: Raintree Steck-Vaughn Company ISBN 0750234199.
- African giraffes highly endangered: study. AFP (2007-12-22)