Friday, 23 March 2012
Thursday, 22 March 2012
the dog
- The domestic dog (Canis lupus familiaris),[2][3] is a subspecies of the gray wolf (Canis lupus), a member of the Canidae family of the mammilian order "Carnivora". The term "domestic dog" is generally used for both domesticated and feral varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in human history. The word "dog" may also mean the male of a canine species,[4] as opposed to the word "bitch" for the female of the species.
- The present lineage of dogs was domesticated from gray wolves about 15,000 years ago.[5] Remains of domesticated dogs have been found in Siberia and Belgium from about 33,000 years ago. The earlier specimens not only show shortening of the snout but widening of the muzzle and some crowding of teeth making them clearly domesticated dogs and not wolves. There are more sites of varying ages in and around Europe and Asia younger than 33,000 years ago but significantly older than 15,000 years ago. None of these early domestication lineages seem to have survived the Last Glacial Maximum. Although mDNA suggest a split between dogs and wolves around 100,000 years ago no specimens predate 33,000 years ago that are clearly morphologically domesticated dog.[6][7][8]
- Dogs' value to early human hunter-gatherers led to them quickly becoming ubiquitous across world cultures. Dogs perform many roles for people, such as hunting, herding, pulling loads, protection, assisting police and military, companionship, and, more recently, aiding handicapped individuals. This impact on human society has given them the nickname "Man's Best Friend" in the Western world. In some cultures, dogs are also an important source of meat.[9][10] In 2001, there were estimated to be 400 million dogs in the world.[11]
- Most breeds of dogs are at most a few hundred years old, having been artificially selected for particular morphologies and behaviors by people for specific functional roles. Through this selective breeding, the dog has developed into hundreds of varied breeds, and shows more behavioral and morphological variation than any other land mammal.[12] For example, height measured to the withers ranges from a 2 inches (51 mm) in the Chihuahua to a 2 feet (0.61 m) in the Irish Wolfhound; color varies from white through grays (usually called "blue") to black, and browns from light (tan) to dark ("red" or "chocolate") in a wide variation of patterns; coats can be short or long, coarse-haired to wool-like, straight, curly, or smooth.[13] It is common for most breeds to shed this coat.
Wednesday, 14 March 2012
the lion
The lion (Panthera leo) is one of the four big cats in the genus Panthera, and a member of the family Felidae. With some males exceeding 250 kg (550 lb) in weight,[4] it is the second-largest living cat after the tiger. Wild lions currently exist in Sub-Saharan Africa and in Asia with an endangered remnant population in Gir Forest National Park in India, having disappeared from North Africa and Southwest Asia in historic times. Until the late Pleistocene, about 10,000 years ago, the lion was the most widespread large land mammal after humans. They were found in most of Africa, across Eurasia from western Europe to India, and in the Americas from the Yukon to Peru.[5] The lion is a vulnerable species, having seen a possibly irreversible population decline of thirty to fifty percent over the past two decades in its African range.[2] Lion populations are untenable outside designated reserves and national parks. Although the cause of the decline is not fully understood, habitat loss and conflicts with humans are currently the greatest causes of concern. Within Africa, the West African lion population is particularly endangered.
Lions live for ten to fourteen years in the wild, while in captivity they can live longer than twenty years. In the wild, males seldom live longer than ten years, as injuries sustained from continual fighting with rival males greatly reduce their longevity.[6] They typically inhabit savanna and grassland, although they may take to bush and forest. Lions are unusually social compared to other cats. A pride of lions consists of related females and offspring and a small number of adult males. Groups of female lions typically hunt together, preying mostly on large ungulates. Lions are apex and keystone predators, although they scavenge as opportunity allows. While lions do not typically hunt humans, some have been known to do so.
the giraffe
The giraffe (Giraffa camelopardalis) is an African even-toed ungulate mammal, the tallest living terrestrial animal and the largest ruminant. Its specific name refers to its camel-like face and patches of color on a light background, which bear a vague resemblance to a leopard's spots. The giraffe is also noted for its extremely long neck and legs and prominent horns. It stands 5–6 m (16–20 ft) tall and has an average weight of 1,200 kg (2,600 lb) for males and 830 kg (1,800 lb) for females. It is classified under the family Giraffidae, along with its closest extant relative, the okapi. There are nine subspecies, which differ in size, coloration, pattern, and range.
The giraffe's scattered range extends from Chad in the north to South Africa in the south and from Niger in the west to Somalia in the east. Giraffes usually inhabit savannas, grasslands, and open woodlands. They prefer areas with plenty of acacia trees, which are important food sources, and can browse at heights that most other herbivores cannot reach. While adults are nearly invulnerable to predation, lions, leopards, spotted hyenas and wild dogs prey on calves. Giraffes commonly gather in aggregations that usually disband every few hours. Males establish social hierarchies through "neckings", which are combat bouts where the neck is used as a weapon. Dominant males gain mating access to females, who bear the sole responsibility for raising the young.
The giraffe has intrigued various cultures, both ancient and modern, for its peculiar appearance, and has often been featured in paintings, novels and cartoons. It is classified by the International Union for Conservation of Nature (IUCN) as Least Concern, but has been extirpated from many parts of its former range, and some subspecies are classified as Endangered. Nevertheless, giraffes are still found in numerous game reserves.
The lion (Panthera leo) is one of the four big cats in the genus Panthera, and a member of the family Felidae. With some males exceeding 250 kg (550 lb) in weight,[4] it is the second-largest living cat after the tiger. Wild lions currently exist in Sub-Saharan Africa and in Asia with an endangered remnant population in Gir Forest National Park in India, having disappeared from North Africa and Southwest Asia in historic times. Until the late Pleistocene, about 10,000 years ago, the lion was the most widespread large land mammal after humans. They were found in most of Africa, across Eurasia from western Europe to India, and in the Americas from the Yukon to Peru.[5] The lion is a vulnerable species, having seen a possibly irreversible population decline of thirty to fifty percent over the past two decades in its African range.[2] Lion populations are untenable outside designated reserves and national parks. Although the cause of the decline is not fully understood, habitat loss and conflicts with humans are currently the greatest causes of concern. Within Africa, the West African lion population is particularly endangered.
Lions live for ten to fourteen years in the wild, while in captivity they can live longer than twenty years. In the wild, males seldom live longer than ten years, as injuries sustained from continual fighting with rival males greatly reduce their longevity.[6] They typically inhabit savanna and grassland, although they may take to bush and forest. Lions are unusually social compared to other cats. A pride of lions consists of related females and offspring and a small number of adult males. Groups of female lions typically hunt together, preying mostly on large ungulates. Lions are apex and keystone predators, although they scavenge as opportunity allows. While lions do not typically hunt humans, some have been known to do so.
the giraffe
The giraffe (Giraffa camelopardalis) is an African even-toed ungulate mammal, the tallest living terrestrial animal and the largest ruminant. Its specific name refers to its camel-like face and patches of color on a light background, which bear a vague resemblance to a leopard's spots. The giraffe is also noted for its extremely long neck and legs and prominent horns. It stands 5–6 m (16–20 ft) tall and has an average weight of 1,200 kg (2,600 lb) for males and 830 kg (1,800 lb) for females. It is classified under the family Giraffidae, along with its closest extant relative, the okapi. There are nine subspecies, which differ in size, coloration, pattern, and range.
The giraffe's scattered range extends from Chad in the north to South Africa in the south and from Niger in the west to Somalia in the east. Giraffes usually inhabit savannas, grasslands, and open woodlands. They prefer areas with plenty of acacia trees, which are important food sources, and can browse at heights that most other herbivores cannot reach. While adults are nearly invulnerable to predation, lions, leopards, spotted hyenas and wild dogs prey on calves. Giraffes commonly gather in aggregations that usually disband every few hours. Males establish social hierarchies through "neckings", which are combat bouts where the neck is used as a weapon. Dominant males gain mating access to females, who bear the sole responsibility for raising the young.
The giraffe has intrigued various cultures, both ancient and modern, for its peculiar appearance, and has often been featured in paintings, novels and cartoons. It is classified by the International Union for Conservation of Nature (IUCN) as Least Concern, but has been extirpated from many parts of its former range, and some subspecies are classified as Endangered. Nevertheless, giraffes are still found in numerous game reserves.
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