Monday, November 25, 2019
Giraffe Facts Giraffes (Giraffa camelopardalis) are quadrupeds, four-legged hooved mammals who roam the savannas and woodlands of Africa. Their long necks, richly patterned coats, and stubby ossicones on their heads make them the most easily recognizable of all the animals on earth.Ã Fast Facts: Giraffe Scientific Name: Giraffa camelopardalisCommon Name(s): Nubian giraffe, reticulated giraffe, Angolan giraffe, Kordofan giraffe, Masai giraffe, South African giraffe, West African giraffe, Rhodesian giraffe, and Rothschilds giraffeBasic Animal Group: MammalSize: 16Ã¢â¬â20 feetWeight: 1,600Ã¢â¬â3,000 poundsLifespan: 20Ã¢â¬â30 yearsDiet: HerbivoreHabitat: Woodland and savanna AfricaPopulation: UnknownConservation Status: Vulnerable Description Technically, giraffes are classified as artiodactyls, or even-toed ungulates- which puts them in the same mammalian family as whales, pigs, deer, and cows, all of which evolved from a last common ancestor that probably lived sometime during the Eocene epoch, about 50 million years ago. Like most artiodactyls, giraffes are sexually dimorphic- that is, males are significantly bigger than females, and the ossicones atop their heads have a slightly different appearance. When fully grown, male giraffes can attain a height of almost 20 feet- most of that, of course, taken up by this mammals elongated neck- and weigh between 2,400 and 3,000 pounds. Females weigh between 1,600 and 2,600 pounds and stand about 16 feet tall. That makes the giraffe the tallest living animal on earth. On the top of a giraffes head are ossicones, unique structures that are neither horns nor ornamental bumps; rather, theyre hardened bits of cartilage covered by skin and anchored firmly to the animals skull. Its unclear what the purpose of ossicones are; they may help males to intimidate one another during mating season, they may be a sexually selected characteristic (that is, males with more impressive ossicones may be more attractive to females), or they may even help to dissipate heat in the blazing African sun.Ã Ã Anton Petrus / Getty Images Species and Subspecies Traditionally, all giraffes belong to the same genus and species, Giraffa camelopardalis. Naturalists have recognized nine separate subspecies: the Nubian giraffe, the reticulated giraffe, the Angolan giraffe, the Kordofan giraffe, the Masai giraffe, the South African giraffe, the West African giraffe, the Rhodesian giraffe, and Rothschilds giraffe. Most zoo giraffes are either the reticulated or Rothschild variety, which are roughly comparable in size but can be distinguished by the patterns of their coats. German ecologist Axel Janke has argued that multi-local DNA analysis of giraffe genetic structure shows that there are actually four separate giraffe species: Northern giraffe (G. cameloparalis, and including Nubian and Rothschilds, with Korofan and West African as subspecies),Reticulated giraffe (G. reticulata),Masai giraffe (G. tippelskirchi, now known as Rhodesian or Thornicrofts giraffe), andSouthern giraffe (G. giraffa, with two subspecies the Angolan and South African giraffes). These suggestions are not accepted by all scholars. Habitat Giraffes range in the wild throughout Africa, but are most often found are in combined savannas and woodlands. They are social creatures who mostly live in one of two types of herds: adult females and their offspring, and bachelor herds. There are also isolates, male bulls who live alone. The most common herd is made up of adult females and their calves, and a few males- these are typically between 10 and 20 individuals, although some can grow as large as 50. Typically, such herds are egalitarian, with no clear leaders or pecking order. Studies show that giraffe cows stay with the same group at least as long as six years. Young bachelor males who are old enough to fend for themselves form temporary herds of between 10 and 20, essentially training camps in which they play and challenge each other before leaving the group to become isolates. They practice what adult males do during mating season, for instance: male giraffes will engage in necking, in which two combatants jostle one another and attempt to land blows with their ossicones. Yann Arthus-Bertrand / Getty Images Diet and Behavior Giraffes subsist on a variable vegetarian diet that includes leaves, stems, flowers, and fruits. Like camels, they dont need to drink on a daily basis. They have a diverse diet which can include as much as 93 different species of plants; but typically, only about a half dozen of those plants make up 75 percent of their summer diets. The main plant varies between members of the Acacia tree; giraffes are the only predator for acacia trees over 10 feet tall.Ã Ã Giraffes are ruminants, mammals equipped with specialized stomachs that pre-digest their food; theyre constantly chewing their cud, a mass of semi-digested food ejected from their stomach and in need of further breakdown. Herds forage together. Each adult giraffe weighs about 1,700 pounds and needs as much as 75 pounds of plants each day. Herds have a home range that averages about 100 square miles, and the herds intersect, sharing one anothers ranges without a social issue.Ã Pal Teravagimov Photography/Getty Images Reproduction and Offspring Granted, very few animals (other than humans) tend to linger in the act of mating, but at least giraffes have a good reason to rush. During copulation, male giraffes stand almost straight up on their hind legs, resting their front legs along the females flanks, an awkward posture that would be unsustainable for more than a few minutes. Interestingly, giraffe sex can provide clues about how dinosaurs like Apatosaurus and Diplodocus had sex- doubtless equally quickly, and with roughly the same posture. The gestation period for giraffes is approximately 15 months. At birth, calves are about five and a half feet tall, and at about one-year-old, they are 10.5 feet tall. Giraffes are weaned at 15Ã¢â¬â18 months, although some suckle up to 22 months of age. Sexual maturation occurs about 5 years of age, and females generally have their first calves at 5Ã¢â¬â6 years. Ã brytta/Getty Images Threats Once a giraffe has reached its adult size, its extremely unusual for it to be attacked, much less killed, by lions or hyenas; instead, these predators will target juvenile, sick, or aged individuals. However, an insufficiently wary giraffe can easily be ambushed at a water hole, since it has to adopt an ungainly posture when taking a drink. Nile crocodiles have been known to chomp on the necks of full-grown giraffes, drag them into the water, and feast at leisure on their copious carcasses. BirdImagesÃ / Getty Images Conservation Status Giraffes are classed as vulnerable by the International Union for Conservation of Nature (IUCN), because of ongoing habitat loss (deforestation, land use conversion, expansion of agriculture and human population growth), civil unrest (ethnic violence, rebel militias, paramilitary and military operations), illegal hunting (poaching), and ecological changes (climate change, mining activity).Ã In some countries in southern Africa, hunting giraffes is legal, especially where populations are increasing. In other countries, such as Tanzania, poaching is associated with declines.Ã Sources Bercovitch, Fred B., et al. How Many Species of Giraffe Are There? Current Biology 27.4 (2017): R136Ã¢â¬âR37. Print.Carter, Kerryn D., et al. Social Networks, Long-Term Associations and Age-Related Sociability of Wild Giraffes. Animal Behaviour 86.5 (2013): 901Ã¢â¬â10. Print.Dagg, Anne Innis. Giraffe: Biology, Behaviour, and Conservation. Cambridge: Cambridge University Press, 2014.Deacon, Francois, and Nico Smit. Spatial Ecology and Habitat Use of Giraffe (Giraffa Camelopardalis) in South Africa. Basic and Applied Ecology 21 (2017): 55Ã¢â¬â65. Print.Fennessy, Julian, et al. Multi-Locus Analyses Reveal Four Giraffe Species Instead of One. Current Biology 26.18 (2016): 2543Ã¢â¬â49. Print.Lee, D. E., and M. K. L. Strauss. Giraffe Demography and Population Ecology. Reference Module in Earth Systems and Environmental Sciences. Elsevier, 2016. Print.Muller, Z. et al. Giraffa camelopardalis (amended version of 2016 assessment). The IUCN Red List of Threatened Species 2018: e.T9 194A136266699, 2018. Shorrocks, Bryan. The Giraffe: Biology, Ecology, Evolution and Behavior. Oxford: John Wiley and Sons, 2016.