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#1 Re: Ganesh's Puzzles » Oral puzzles » Today 15:53:05

Hi,

.

#4258. G spends 50% of his monthly income on household items and out of the remaining, he spends 50% on transport, 25% on entertainment, 10% on sports and the remaining amount of $900 is saved. What is G's monthly income?

#2 Re: Ganesh's Puzzles » 10 second questions » Today 15:41:54

Hi,

The solution

is correct. Excellent, Monox D. I-Fly!

#7093. Find the value of 33.5% of 250.

#3 Re: Ganesh's Puzzles » Mensuration » Today 15:21:27

Hi,

.

M # 459. The curved surface area of a right circular cone of radius 14 centimeters is 440 square centimeters. What is the slant height of the cone? Use

.

#4 Jokes » Cloud Jokes » Today 01:12:42

ganesh
Replies: 0

Questions and Answers : Cloud Jokes
* * *
Q: What cloud is so lazy because it will not get up?
A: Fog.
* * *
Q: Why don't meteorologists like to dine out on the moon?
A: The moon has no atmosphere.
* * *
Q: What did one raindrop say to the other?
A: Two's company, three's a cloud.
* * *
Q: How can you wrap a cloud?
A: With a rainbow.
* * *
Q: What is a clouds favorite drink?
A: Mountain Dew.
* * *
Q: What is it called when a high pressure goes on vacation?
A: A Hiatus.
* * *
Q: What do clouds want to be when they grow up?
A: Thunderstorms.
* * *
Q: When is Monday coming?
A: MonSoon!
* * *

#5 Re: This is Cool » Miscellany » Today 01:03:00

233) Nitric Acid

Nitric acid (HNO3) is a colorless, liquid acid widely used in the manufacturing of explosives and fertilizers . When dissolved in water , molecules of nitric acid separate (or dissociate) into hydrogen ions (H+) and nitrate ions (NO3). The fact that nearly every nitric acid molecule dissociates is what makes nitric acid a strong acid. Nitric acid is often the starting material in the industrial production of nitrates for fertilizers.

Plants take up nitrogen from the soil in the form of ammonium ions (NH +4 ) and nitrate ions, and along with carbon containing molecules made during photosynthesis , these ions are used to synthesize amino acids, from which proteins are made. Within the past hundred years the demand for nitrogen fertilizers has grown dramatically as the need for fertilizers for agriculture has grown. The natural manner in which nitrates reach the soil involves the reaction of nitrogen gas and oxygen gas in the atmosphere to form nitrogen dioxide gas (NO2), which then reacts with atmospheric water, making nitric acid, which provides a natural source of nitrates in water and soil.

During World War I, the Germans were very interested in using ammonium nitrate (NH4NO3), a salt of nitric acid, as an explosive. Many organic nitrates such as nitroglycerine and TNT are also highly explosive. Nitric acid is made by the reaction of ammonia with oxygen gas. The nitric acid which is produced can then be used to make a variety of compounds. This is a process that has allowed large amounts of fertilizers to be produced relatively inexpensively.

Nitric acid is also formed from the reaction of nitrogen oxides produced during the combustion (burning) of fossil fuels in automobile engines. These nitrogen oxides react with water in the atmosphere and form nitric acid, one cause of acid rain . High levels of nitrates in drinking water can contribute to the formation of nitrosamines, a group of carcinogenic (cancer causing) compounds.

Nitrc-acid-and-oxides-of-nitrogen-300x197.png

#6 Re: Ganesh's Puzzles » 10 second questions » Yesterday 20:59:35

Hi,

A Wee Bit Lack of Concentration, Monox D. I-Fly!

#7092. Find the value of j.

.

#7 Re: Ganesh's Puzzles » Oral puzzles » Yesterday 20:42:34

Hi,

Nevermind, Monox D. I-Fly! Our dear fiend, bobbym, who is not with us now, often said it happened to all, and it was nothing to worry! I too make too many mistakes when I am in a hurry!

.

#4257. A Human Resources Company employs 4800 people, out of which 45% are males and 60% of the males are either 25 years or older. How many males are employed in the Human Resources Company who are younger than 25 years?

#8 Re: Ganesh's Puzzles » 10 second questions » Yesterday 17:17:39

Hi,

.

#7091. Find the value of m.

#9 Re: Ganesh's Puzzles » Mensuration » Yesterday 17:01:50

Hi,

M # 458. The diameter of the base of a right circular cone is 7 centimeters and the slant height is 10 centimeters. What is the Lateral Surface Area? Use

.

#10 Re: Ganesh's Puzzles » Oral puzzles » Yesterday 15:56:38

Hi,

Good attempt, Monox D. I-Fly!

Hope you have recovered fully after the cataract surgery!

#4256. Five-ninths of a number is equal to twenty-five percent of the second number. The second number is equal to one-fourth of the third number. The value of the third number is 2960. What is 30 percent of the first number?

#11 Re: Dark Discussions at Cafe Infinity » crème de la crème » Yesterday 01:33:12

412) Ottó Bláthy

Ottó Titusz Bláthy (11 August 1860 – 26 September 1939) was a Hungarian electrical engineer. In his career, he became the co-inventor of the modern electric transformer, the tension regulator, the AC watt-hour meter. motor capacitor for the single-phase (AC) electric motor, the turbo generator, and the high-efficiency turbo generator.

Bláthy's career as an inventor began during his time at the Ganz Works in 1883. There, he conducted experiments for creating a transformer. It is noteworthy that the name "transformer" was created by Bláthy. In 1885 the ZBD model alternating-current transformer was invented by three Hungarian engineers: Ottó Bláthy, Miksa Déri and Károly Zipernowsky. (ZBD comes from the initials of their names). In the autumn of 1889 he patented the AC watt-meter.

Early life

He attended schools in Tata and Vienna, where he obtained diploma of machinery in 1882. Between 1881 and 1883 he worked at the machinery workshop of the Hungarian Railways (MAV). Attracted by the successes of Károly Zipernowsky, he joined his team on 1 July 1883. He admitted he had learnt nothing about electrotechnics in university, so he started to learn about the theory himself. Using the Maxwell equations he invented a practical approach of sizing magnetic coils. Kapp and Hopkinson (for whom Hopkinson's law is named) only published their findings later in 1886, and 1887.

Professional life

His practical calculation method was crucial in building the first practical transformer. Based on his findings, he rebuilt his machines in 1883 and obtained better efficiency with the same weight. He was the first to investigate the heat dissipation problems of electric motors, and at that time the connection between current density and heat was determined.

At the Turin Italian National Exhibition in 1884, he saw Gaulard and Gibbs's "secondary generator"' (i.e. AC transformer) system, and he decided to improve it. Including a closed-loop magnetic field, based on the findings of Faraday, he conducted experiments with Miksa Déri in the summer of 1884 at the Ganz factory. Based on these experiments, they invented the transformer in 1885, which was unveiled at the Budapest National Exhibition in 1885.

Based on the opinions of Galileo Ferraris, the Italian government ordered a power transformer for Rome, which was installed in October 1886. Later, they designed a power plant for Tivoli, built by Ganz, with six water turbines and 5000 V, which were worked in parallel with the old steam engine generators. This was the first time in history two high-voltage power plants were connected.

His other invention, the electricity meter, was first introduced to the market in 1889. He tried to improve it and decrease its weight.

Chess works

Besides his scientific work, Bláthy is well known as an author of chess problems. He specialized in the field of very long moremovers, also known as longmovers. problems).

titusz5.jpg

#12 Re: Ganesh's Puzzles » English language puzzles » Yesterday 01:14:01

Hi,

#3107. What does the noun deception mean?

#3108. What does the noun decibel mean?

#13 Re: Ganesh's Puzzles » General Quiz » Yesterday 00:58:58

Hi,

#7121. Name the largest city in Canada by population.

#7122. Hoover Dam is on the banks of which river?

#14 Re: Ganesh's Puzzles » 10 second questions » 2018-10-20 14:46:08

Hi,

.

#7090. Find the value of d:

.

#15 Re: Ganesh's Puzzles » Oral puzzles » 2018-10-20 14:37:46

Hi,

.

#4255. Albert spends 25 percent of his salary on house rent, 5 percent on food, 15 percent on travel, 10 percent on clothes, and the remaining amount of $27,000 is saved. What is Albert's income?

#16 Re: Ganesh's Puzzles » Mensuration » 2018-10-20 14:14:55

Hi,

M # 457. In a right circular cylinder, the height is 2 centimeters less than the diameter and the ratio of the radius and its height is 7:5, what is the volume of the cylinder?

#17 Jokes » Lamb Jokes » 2018-10-20 00:26:13

ganesh
Replies: 0

Q: What do you call a lamb covered in chocolate?
A: A Candy Baa.
* * *
Q: What do you get if you cross an angry sheep and a moody cow?
A: An animal that's in a baaaaaaaad moooooood.
* * *
Q: What do you get if you cross a boa and a sheep?
A: A wrap-around sweater.
* * *
Q: How do lamb greet each other at Christmas?
A: Merry Christmas to Ewe!
* * *
Q: What animal sounds like a lamb but isn't?
A: A baaaa-boon!
* * *
Q: What do you call a dancing lamb?
A: A baa-lerina!
* * *
Q: What do you get when you cross a lamb and a porcupine?
A: An animal that can sew its own sweaters.
* * *
Q: Where do lambs take a bath?
A: In a baaaa-th tub!
* * *
Q: What did the lamb want to do?
A: To wool the world.
* * *
Q: Why was the lamb arrested on the freeway?
A: Because she did a ewe-turn!
* * *
Q: Where do lambs go on vacation?
A: To the Baaaaaahamas.
* * *
Q: Why couldn't the little lamb play outside?
A: It was being baaaaaaaad!
* * *
Q: What kind of car does a sheep like to drive?
A: A Lamborghini.
* * *
Q: What is a sheep's favorite newspaper?
A: "The Wool Street Journal".
* * *

#18 Re: This is Cool » Miscellany » 2018-10-20 00:14:46

232) Andes

The Andes or Andean Mountains (Spanish: Cordillera de los Andes) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America.

The Andes is South America's longest mountain range, forming a continuous chain of highland along the western coast of South America. It is over 4,400 miles (7,000 km) long, 200 miles (300 km) wide throughout its length (except in the Bolivian flexure where it is 640 km wide) with an average height of about 13,000 feet (4,000 m).

The Andes is the highest mountain range outside Asia, with the highest peak, Aconcagua, rising to 22,834 feet (6,960 m) above sea level. The summit of Mount Chimborazo in the Ecuadorean Andes is the point on the Earth's surface most distant from its center, because of the equatorial bulge.

The name Andes comes from the Quechua word anti, which means "high crest." Another theory says that the name Andes derived from the Spanish word "anden" which means terrace in reference to the cultivation terraces used by the Incas and other related peoples.

Physical features

The Andes Mountains extend over seven countries: Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, and Venezuela, some of which are known as Andean States. The islands of Aruba, Bonaire, and Curaçao, which lie in the Caribbean Sea off the coast of Venezuela, represent the submerged peaks of the extreme northern edge of the Andes range. They are not a single line of peaks, but instead a succession of parallel and transverse mountain ranges.

The Andes can be divided into three sections: the Southern Andes in Argentina and Chile; the Central Andes, including the Chilean and Peruvian cordilleras (from the Spanish word meaning "rope"); and the northern section in Venezuela, Colombia, and northern Ecuador consisting of two parallel ranges, the Cordillera Occidental and the Cordillera Oriental. These ranges are often separated by a deep intermediate depressions. Other small chains arise on the sides of the great chains.

The Cordillera de la Costa starts from the southern extremity of the continent and runs in a northerly direction, parallel with the coast, being broken up at its beginning into a number of islands and afterwards forming the western boundary of the great central valley of Chile. To the north this coastal chain continues in small ridges or isolated hills along the Pacific Ocean as far as Venezuela, always leaving the same valley more or less visible to the west of the western great chain.

Geology

The Andes fundamentally are the result of plate tectonics processes, caused by the subduction of the Nazca plate beneath the South American plate. The boundary between the two plates is marked by the Peru-Chile oceanic trench. The descending Nazca plate is a young and buoyant lithosphere, which resists subduction, causing many earthquakes.

The formation of the Andes began in the Jurassic period, but it was during the Cretaceous Period that the Andes began to take their present form, by the uplifting, faulting and folding of sedimentary and metamorphic rocks of the ancient cratons to the east. Tectonic forces along the subduction zone along the entire west coast of South America where the Nazca Plate and a part of the Antarctic Plate are sliding beneath the South American Plate continue to produce an ongoing orogenic event resulting in minor to major earthquakes and volcanic eruptions. In the extreme south, a major transform fault separates Tierra del Fuego from the small Scotia Plate. Across the 600 mile (1,000 km) wide Drake Passage lie the mountains of the Antarctic Peninsula south of the Scotia Plate which appear to be a continuation of the Andes chain.

The Andes range has many active volcanoes, including Cotopaxi, one of the highest active volcanoes in the world.

Climate

The climate in the Andes varies greatly depending on location, altitude, and proximity to the sea. The southern section is rainy and cool, the central Andes are dry with large variations in temperature. The northern Andes are typically rainy and warm. The climate is known to change drastically. Tropical rainforests exist just miles away from the snow covered peak, Cotopaxi.

The mountains have a large effect on the temperatures of nearby areas. The snow line depends on the location. It is at between 4,500–4,800 m in the tropical Ecuadorian, Colombian, Venezuelan, and northern Peruvian Andes, rising to 4,800–5,200 m in the drier mountains of southern Peru south to northern Chile south to about 30°S, then descending to 4,500 m on Aconcagua at 32°S, 2,000 m at 40°S, 500 m at 50°S, and only 300 m in Tierra del Fuego at 55°S; from 50°S, several of the larger glaciers descend to sea level.

Plant and animal life

Tropical rainforests and rainforests encircle the northern Andes. The cinchona, a source of quinine which is used to treat malaria, is found in the Bolivian Andes. The high-altitude Polylepis forests are present in the Andean areas of Ecuador, Peru, and Bolivia. The trees, Queñua and Yagual, can be found at altitudes of 4,500 m above sea level. Once abundant, the forests began disappearing during the Incan period when much of it was used for building material and cooking fuel. The trees are now considered to be highly endangered with only 10 percent of the original forests remaining.

The llama can be found living at high altitudes, predominantly in the Peru and Bolivia. The alpaca, a type of llama, is raised for its wool. The nocturnal chinchilla, an endangered member of the rodent order, inhabits the Andes' alpine regions. The South American condor is the largest bird of its kind in the Western hemisphere. Other animals include the huemul, cougar, camelids and, for birds, the partridge, parina, huallata, and coot. Llamas and cougars play important roles in many Andean cultures.

The people

History

The Inca Civilization developed in the northern Andes during the 1400s. The Incas formed this civilization through careful and meticulous governmental management. The government sponsored the construction of aqueducts and roads, some of which, like those created by the Romans, are still in existence today. The aqueducts turned the previously scattered Incan tribe into the agricultural and eventually militaristic masters of the region.

Devastated by deadly European diseases to which they had no immunity, the Incas were conquered by an army of 180 men led by Pizarro in 1532. One of the few Inca cities the Spanish never found in their conquest was Machu Picchu, which lay hidden on a peak on the edge of the Andes where they descend to the Amazon. Machu Picchu (sometimes called the "Lost City of the Incas") is one of the most well known sites of the Inca Empire. The ruin, located high in the Andes Mountains, is one of the most important archaeological centers in South America, and as a consequence, the most visited tourist attraction in Peru. This UNESCO World Heritage Site remains an incredible combination of natural beauty and human creativity.

Modern history

The ancient peoples of the Andes have practiced irrigation techniques for over 6,000 years. Because of the mountain slopes, terracing has been a common practice. Maize and barley were important crops for these people. Currently, tobacco, cotton, and coffee are the main export crops. The potato holds a very important role as an internally consumed crop.

By far the most important plant in terms of history and culture is cocoa, the leaves of which have been central to the Andean people for centuries. Coca has been a staple dietary supplement and cornerstone to Andean culture throughout much of its history. Unprocessed coca leaves are commonly used in the Andean countries to make an herbal tea with mild stimulant effects similar to strong coffee, but is best known in most of the world for the stimulant drug cocaine that is chemically extracted from its new fresh leaf tips in a similar fashion to tea bush harvesting.

Mining is quite prosperous in the Andes, with iron, gold, silver, and copper being the main production minerals. The Andes are reputed to be one of the most important sources of these minerals in the world.

The people of the Andes are not well connected to urban regions. Due to the arduous terrain, vehicles are of little use. People generally walk to their destinations, using the llama as their primary pack animal.

The main surviving languages of the Andean peoples are those of the Quechua and Aymara language families.

Andes-300x177.gif

#20 Re: Ganesh's Puzzles » Oral puzzles » 2018-10-19 16:20:36

Hi,

#4254. In an Entrance Examination, Ritu scored 56% marks, Smita scored 92% marks, and Rina scored 634 marks. The maximum marks of the examination are 875. What is the average marks scored by all the three girls together?

#21 Re: Ganesh's Puzzles » Mensuration » 2018-10-19 15:47:30

Hi,

M # 456. Find the total surface area of a right circular cylinder whose height is 12 centimeters and radius 2 centimeters. Use

.

#22 Re: Ganesh's Puzzles » English language puzzles » 2018-10-19 01:15:06

Hi,

#3105. What does the noun deceit mean?

#3106. What does the verb (used with object) decelerate mean?

#23 Re: Dark Discussions at Cafe Infinity » crème de la crème » 2018-10-19 00:46:41

411) Melitta Bentz

Amalie Auguste Melitta Bentz (31 January 1873 – 29 June 1950), born Amalie Auguste Melitta Liebscher, was a German entrepreneur who invented the coffee filter in 1908.

Biography

Bentz was born in Dresden. Her father was a publisher.

As a housewife, Bentz found that percolators were prone to over-brewing the coffee, espresso-type machines at the time tended to leave grounds in the drink, and linen bag filters were tiresome to clean. She experimented with many means, but ended up using blotting paper from her son Willi's school exercise book and a brass pot perforated using a nail. When the grounds-free, less bitter coffee met with general enthusiasm, she decided to set up a business. The Kaiserliche Patentamt (Imperial Patent Office) granted her a patent on 20 June 1908, and on 15 December the company was entered into the commercial register with 73 Pfennig as "M. Bentz." After contracting a tinsmith to manufacture the devices, they sold 1,200 coffee filters at the 1909 Leipzig fair.

Her husband Hugo and their sons Horst and Willi were the first employees of the emerging company. In 1910, the company won a gold medal at the International Health Exhibition and a silver medal at the Saxon Innkeepers' Association. When the First World War erupted, metals were requisitioned for use in zeppelin construction, her husband was conscripted to Romania, paper was rationed, and coffee beans import was impossible due to the British blockade, disrupting the normal business. During this time she supported herself by selling cartons.

Continuing expansion caused them to move their business several times within Dresden. By 1928 the demand for their products was so high that the 80 workers had to work in a double-shift system. As no satisfactory production facilities could be found in Dresden, the fast-growing company moved in 1929 to Minden in eastern Westphalia. By that time 100,000 filters had been produced.

Horst took over the company, now "Bentz & Sohn," in 1930. She transferred the majority stake in Melitta-Werke Aktiengesellschaft to Horst and Willi in 1932, but kept a hand in the business, ensuring that the employees were cared for, offering Christmas bonuses, increasing vacation days from 6 to 15 days per year, and reducing the working week to 5 days. Bentz fostered the company's “Melitta Aid” system, a social fund for company employees.

After the outbreak of World War II, production stopped and the company was ordered to produce goods to aid the war effort. At the conclusion of war, the workers relocated for a time to old factories, barracks, even pubs, because the surviving portions of the main factory had been requisitioned as a provisional administration for the Allied troops, a condition that held for twelve years. By 1948, production of filters and paper had resumed, and at the time of her death at Holzhausen at Porta Westfalica in 1950, the company had reached 4.7 million Deutsche marks.

Legacy

The grandchildren of Melitta Bentz, Thomas and Stephen Bentz, still control the Melitta Group KG headquartered in Minden in the east of North Rhine-Westphalia, with some 3,300 employees in 50 companies.

melitta-bentz.jpg

#24 Re: Introductions » trigonometry » 2018-10-18 23:11:22

Hi avaeliza,

Welcome to the forum!

Homework has to be done my the individual. However, the hints are given in the links.

Right Angled Triangle and Pythagoras Theorem.

If there is a specific problem, or two, a solution can be provided.

Ganesh.

#25 Re: This is Cool » Miscellany » 2018-10-18 17:54:05

231) Giraffe

Giraffe, (genus Giraffa), any of four species in the genus Giraffa of long-necked cud-chewing hoofed mammals of Africa, with long legs and a coat pattern of irregular brown patches on a light background. Giraffes are the tallest of all land animals; males (bulls) may exceed 5.5 metres (18 feet) in height, and the tallest females (cows) are about 4.5 metres. Using prehensile tongues almost half a metre long, they are able to browse foliage almost six metres from the ground. Giraffes are a common sight in grasslands and open woodlands in East Africa, where they can be seen in reserves such as Tanzania’s Serengeti National Park and Kenya’s Amboseli National Park. The genus Giraffa is made up of the northern giraffe (G. camelopardalis), the southern giraffe (G. giraffa), the Masai giraffe(G. tippelskirchi), and the reticulated giraffe (G. reticulata).

Giraffes grow to nearly their full height by four years of age but gain weight until they are seven or eight. Males weigh up to 1,930 kg (4,250 pounds), females up to 1,180 kg (2,600 pounds). The tail may be a metre in length and has a long black tuft on the end; there is also a short black mane. Both sexes have a pair of horns, though males possess other bony protuberances on the skull. The back slopes downward to the hindquarters, a silhouette explained mainly by large muscles that support the neck; these muscles are attached to long spines on the vertebrae of the upper back. There are only seven neck (cervical) vertebrae, but they are elongated. Thick-walled arteries in the neck have extra valves to counteract gravity when the head is up; when the giraffe lowers its head to the ground, special vessels at the base of the brain control blood pressure.

The gait of the giraffe is a pace (both legs on one side move together). In a gallop, it pushes off with the hind legs, and the front legs come down almost together, but no two hooves touch the ground at the same time. The neck flexes so that balance is maintained. Speeds of 50 km (31 miles) per hour can be maintained for several kilometres, but 60 km (37 miles) per hour can be attained over short distances. Arabs say of a good horse that it can “outpace a giraffe.”

Giraffes live in nonterritorial groups of up to 20. Home ranges are as small as 85 square km (33 square miles) in wetter areas but up to 1,500 square km (580 square miles) in dry regions. The animals are gregarious, a behaviour that apparently allows for increased vigilance against predators. They have excellent eyesight, and when one giraffe stares, for example, at a lion a kilometre away, the others look in that direction too. Giraffes live up to 26 years in the wild and slightly longer in captivity.

Giraffes prefer to eat new shoots and leaves, mainly from the thorny acacia tree. Cows in particular select high-energy low-fibre items. They are prodigious eaters, and a large male consumes about 65 kg (145 pounds) of food per day. The tongue and inside of the mouth are coated with tough tissue as protection. The giraffe grasps leaves with its prehensile lips or tongue and pulls them into the mouth. If the foliage is not thorny, the giraffe “combs” leaves from the stem by pulling it across the lower canine and incisor teeth. Giraffes obtain most water from their food, though in the dry season they drink at least every three days. They must spread the forelegs apart in order to reach the ground with the head.

Females first breed at four or five years of age. Gestation is 15 months, and, though most calves are born in dry months in some areas, births can take place in any month of the year. The single offspring is about 2 metres (6 feet) tall and weighs 100 kg (220 pounds). For a week the mother licks and nuzzles her calf in isolation while they learn each other’s scent. Thereafter, the calf joins a “nursery group” of similar-aged youngsters, while mothers forage at variable distances. If lions or hyenas attack, a mother sometimes stands over her calf, kicking at the predators with front and back legs. Cows have food and water requirements that may keep them away from the nursery group for hours at a time, and about half of very young calves are killed by lions and hyenas. Calves sample vegetation at three weeks but suckle for 18–22 months. Males join other bachelors when one to two years old, whereas daughters are likely to stay near the mother.

Bulls eight years and older travel up to 20 km per day looking for cows in heat (estrus). Younger males spend years in bachelor groups, where they engage in “necking” bouts. These side-to-side clashes of heads cause mild damage, and bone deposits subsequently form around the horns, eyes, and back of the head; a single lump projects from between the eyes. Accumulation of bone deposits continues through life, resulting in skulls weighing 30 kg. Necking also establishes a social hierarchy. Violence sometimes occurs when two older bulls converge on an estrous cow. The advantage of a heavy, knobbed skull is soon apparent. With forelegs braced, bulls swing their necks and club each other with their skulls, aiming for the underbelly. There have been instances of bulls being knocked off their feet or even rendered unconscious.

Paintings of giraffes appear on early Egyptian tombs; just as today, giraffe tails were prized for the long wiry tuft hairs used to weave belts and jewelry. In the 13th century, East Africa supplied a trade in hides. During the 19th and 20th centuries, overhunting, habitat destruction, and rinderpestepidemics introduced by European livestock reduced giraffes to less than half their former range. Today giraffes are numerous in East African countries and also in certain reserves of Southern Africa, where they have enjoyed somewhat of a recovery. The West African subspecies of the northern giraffe is reduced to a small range in Niger.

Giraffes were traditionally classified into one species, Giraffa camelopardalis, and then into several subspecies on the basis of physical features. Nine subspecies were recognized by coat pattern similarities; however, it was also known that individual coat patterns were unique. Some scientists contended that these animals could be divided into six or more species, since studies had shown that differences in genetics, reproductive timing, and pelage patterns (which are indicative of reproductive isolation) exist between various groups. By the 2010s mitochondrial DNA studies had determined that genetic uniquenesses brought on by the reproductive isolation of one group from another were significant enough to separate giraffes into four distinct species.

The giraffe had long been classified as a species of least concern by the International Union for Conservation of Nature (IUCN), which places all giraffes in the species G. camelopardalis. A study in 2016, however, determined that habitat loss resulting from expanding agricultural activities, increased mortality brought on by illegal hunting, and the effects of ongoing civil unrest in a handful of African countries had caused giraffe populations to plummet by 36–40 percent between 1985 and 2015, and, as of 2016, the IUCN has reclassified the conservation status of the species as vulnerable.

The only close relative of the giraffe is the rainforest-dwelling okapi, which is the only other member of the family Giraffidae. G. camelopardalis or something very similar lived in Tanzania two million years ago, but Giraffidae branched off from other members of the order Artiodactyla—cattle, antelope, and deer—about 34 million years ago.

giraffe-1-340x200.jpg

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