Elephant
November 20th, 2008
Elephants are the largest land animals. The elephant's gestation period is 22 months, the longest of any land animal. At birth it is common for an elephant calf to weigh 120 kilograms (260 lb). They typically live for 50 to 70 years, but the oldest recorded elephant lived for 82 years. The largest elephant ever recorded was shot in Angola in 1956. This male weighed about 12,000 kilograms (26,000 lb), with a shoulder height of 4.2 metres (14 ft), a metre (yard) taller than the average male African elephant. The smallest elephants, about the size of a calf or a large pig, were a prehistoric species that lived on the island of Crete during the Pleistocene epoch.
The elephant has appeared in cultures across the world. They are a symbol of wisdom in Asian cultures and are famed for their memory and intelligence, where they are thought to be on par with cetaceans and hominids. Aristotle once said the elephant was "the beast which passeth all others in wit and mind". The word "elephant" has its origins in the Greek ἐλέφας, meaning "ivory" or "elephant".
Healthy adult elephants have no natural predators, although lions may take calves or weak individuals. They are, however, increasingly threatened by human intrusion and poaching. Once numbering in the millions, the African elephant population has dwindled to between 470,000 and 690,000 individuals. The elephant is now a protected species worldwide, with restrictions in place on capture, domestic use, and trade in products such as ivory.
The African Elephant genus contains two (or, arguably, three) living species; whereas, the Asian Elephant species is the only surviving member of the Asian Elephant genus, but can be divided into four subspecies.
Although the fossil evidence is uncertain, scientists discovered genetic evidence that the elephant family shares distant ancestry with the sirenians (sea cows) and the hyraxes through gene comparisons. In the distant past, members of the hyrax family grew to large sizes, and it seems likely that the common ancestor of all three modern families was some kind of amphibious hyracoid. One theory suggests that these animals spent most of their time under water, using their trunks like snorkels for breathing. Modern elephants have retained this ability and are known to swim in that manner for up to 6 hours and 50 km (30 miles).
In the past, there was a much wider variety of elephant genera, including the mammoths, stegodons and deinotheria. There was also a much wider variety of species.
With a mass just over 5 kg (11 lb), elephant brains are larger than those of any other land animal, and although the largest whales have body masses twentyfold those of a typical elephant, whale brains are barely twice the mass of an elephant's. A wide variety of behaviours, including those associated with grief, making music, art, altruism, allomothering, play, use of tools, compassion and self-awareness evidence a highly intelligent species on par with cetaceans and primates. The largest areas in the elephant brain are those responsible for hearing, smell and movement coordination.
Elephants have well innervated trunks, and an exceptional sense of hearing and smell. The hearing receptors reside not only in ears, but also in trunks that are sensitive to vibrations, and most significantly feet, which have special receptors for low frequency sound and are exceptionally well innervated. Elephants communicate by sound over large distances of several kilometers partly through the ground, which is important for their social lives. Elephants are observed listening by putting trunks on the ground and carefully positioning their feet.
Elephant's very good at looking at objects with their eyes. Their eyes are aimed down and to look up they have to put their head up very high, and that is a problem for them.
In addition to their bellows, roars and widely recognized trumpet-like calls; elephants communicate over long distances by producing and receiving low-frequency sound (infrasound), a sub-sonic rumbling, which can travel through the ground farther than sound travels through the air. This can be felt by the sensitive skin of an elephant's feet and trunk, which pick up the resonant vibrations much as the flat skin on the head of a drum. To listen attentively, every member of the herd will lift one foreleg from the ground, and face the source of the sound, or often lay its trunk on the ground. The lifting presumably increases the ground contact and sensitivity of the remaining legs. This ability is thought also to aid their navigation by use of external sources of infrasound. Discovery of this new aspect of elephant social communication and perception came with breakthroughs in audio technology, which can pick up frequencies outside the range of the human ear. Pioneering research in elephant infrasound communication was done by Katy Payne, of the Elephant Listening Project, and is detailed in her book Silent Thunder. Though this research is still in its infancy, it is helping to solve many mysteries, such as how elephants can find distant potential mates, and how social groups are able to coordinate their movements over extensive range.
Although successful hybridisation between African and Asian Elephant species is highly unlikely in the wild, in 1978 at Chester Zoo, an Asian elephant cow gave birth to a hybrid calf sired by an African elephant bull (the old terms are used here as these events pre-date the current classifications). "Motty", the resulting hybrid male calf, had an African elephant's cheeks, their ears (large with pointed lobes) and legs (longer and slimmer), but the toenail numbers, (5 for each front foot, 4 hind) and the single trunk finger of an Asian elephant. His wrinkled trunk was like that of an African elephant. His forehead was sloping with one dome and two smaller domes behind it. The body was African in type, but had an Asian-type centre hump and an African-type rear hump. The calf died of infection 12 days later. It is preserved as a mounted specimen at the British Natural History Museum, London. There are unconfirmed rumours of three other hybrid elephants born in zoos or circuses; all are said to have been deformed and none survived.
Despite its popularity in zoos, and cuddly portrayal as gentle giants in fiction, elephants are among the world's most potentially dangerous animals. They can crush and kill any other land animal, even the rhinoceros. They can experience unexpected bouts of rage, and can be vindictive. In Africa, groups of young teenage elephants attack human villages in what is thought to be revenge for the destruction of their society by massive cullings done in the 1970s and 80s. In India, male elephants attack villages at night, destroying homes and killing people on a regular basis. In the Indian state of Jharkhand, 300 people were killed by elephants between 2000 and 2004, and in Assam, 239 people have been killed by elephants since 2001. In India elephants kills up to 200 humans every year, and in Sri Lanka around 50 per year.
At least a few elephants have been suspected to be drunk during their attacks. In December 1998, a herd of elephants overran a village in India. Although locals reported that nearby elephants had recently been observed drinking beer which rendered them "unpredictable", officials considered it the least likely explanation for the attack. An attack on another Indian village occurred in October 1999, and again locals believed the reason was drunkenness, but the theory was not widely accepted. Purportedly drunk elephants raided yet another Indian village again on December 2002, killing six people, which led to killing of about 200 elephants by locals.
Lion
September 14th, 2008
Should they survive the rigors of cubhood, lionesses in secure habitat such as Kruger National Park may frequently reach an age of 12–14 years whereas lions seldom live for longer than 8 years. However, there are records of lionesses living for up to 20 years in the wild. In captivity both male and female lions can live for over 20 years. 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. The lion is an apex and keystone predator, although they will resort to scavenging if the opportunity arises. While lions, in general, do not selectively hunt humans, some have been known to become man-eaters and seek human prey.
The lion is a vulnerable species, having seen a possibly irreversible population decline of 30 to 50 percent over the past two decades in its African range; populations are untenable outside designated reserves and national parks. Although the cause of the decline is not well understood, habitat loss and conflicts with humans are currently the greatest causes of concern. Lions have been kept in menageries since Roman times and have been a key species sought after and exhibited in zoos the world over since the late eighteenth century. Zoos are cooperating worldwide in breeding programs for the endangered Asiatic subspecies.
Visually, the male is highly distinctive and is easily recognized by its mane. The head of the male lion is one of the most widely recognized animal symbols in human culture. It has been depicted extensively in literature, in sculptures, in paintings, on national flags, and in contemporary films and literature.
The lioness has been recognized, however, as the pinnacle of hunting prowess from the earliest of human writings and graphic representations. The lionesses are the hunters for their pride and capture their prey with precise and complex teamwork. Each lioness develops specific skills for her role in the hunting techniques used by her pride and, generally, assumes that role during most hunts. Members of human cultures living among lions in natural habitats have understood this characteristic and often have chosen the lioness to represent their most ferocious war deities and warriors, often naming their male rulers as her "son". Examples drawn from the earliest of written records include the Egyptian pantheon deities of Sekhmet, Bast, Menhit, and Tefnut, and these deities may have had precursors in Nubia and Lybia. Other Egyptian deities are quite complex and assume aspects that may include one as a lioness headed human or a lioness in specific roles. Depictions of lions hunting in groups have existed from the Upper Paleolithic period, with carvings and paintings from the Lascaux and Chauvet Caves.
The oldest lion-like fossil is known from Laetoli in Tanzania and is perhaps 3.5 million years old; some scientists have identified the material as Panthera leo. These records are not well-substantiated, and all that can be said is that they pertain to a Panthera-like felid. The oldest confirmed records of Panthera leo in Africa are about 2 million years younger. The closest relatives of the lion are the other Panthera species: the tiger, the jaguar, and the leopard. Morphological and genetic studies reveal that the tiger was the first of these recent species to diverge. About 1.9 million years ago the jaguar branched off the remaining group, which contained ancestors of the leopard and lion. The lion and leopard subsequently separated about 1 to 1.25 million years ago from each other.
Panthera leo itself evolved in Africa between 1 million and 800,000 years ago before spreading throughout the Holarctic region. It appeared in Europe for the first time 700,000 years ago with the subspecies Panthera leo fossilis at Isernia in Italy. From this lion derived the later Cave Lion (Panthera leo spelaea), which appeared about 300,000 years ago. During the upper Pleistocene the lion spread to North and South America, and developed into Panthera leo atrox, the American Lion. Lions died out in northern Eurasia and America at the end of the last glaciation, about 10,000 years ago; this may have been secondary to the extinction of Pleistocene megafauna.
While lions do not usually hunt people, some (usually males) seem to seek out human prey; well-publicized cases include the Tsavo maneaters, where 28 railway workers building the Kenya-Uganda Railway were taken by lions over nine months during the construction of a bridge over the Tsavo River in Kenya in 1898, and the 1991 Mfuwe man-eater, which killed six people in the Laungwa River Valley in Zambia. In both, the hunters who killed the lions wrote books detailing the animals' predatory behavior. The Mfuwe and Tsavo incidents bear similarities: the lions in both incidents were larger than normal, lacked manes, and seemed to suffer from tooth decay. The infirmity theory, including tooth decay, is not favored by all researchers. An analysis of teeth and jaws of man-eating lions in museum collections suggests that, while tooth decay may explain some incidents, prey depletion in human-dominated areas is a more likely cause of lion predation on humans. In their analysis of Tsavo and man-eating generally, Kerbis Peterhans and Gnoske acknowledge that sick or injured animals may be more prone to man-eating, but that the behavior is "not unusual, nor necessarily 'aberrant'" where the opportunity exists; if inducements such as access to livestock or human corpses are present, lions will regularly prey upon human beings. The authors note that the relationship is well-attested amongst other pantherines and primates in the paleontological record.
The lion's proclivity for man-eating has been systematically examined. American and Tanzanian scientists report that man-eating behavior in rural areas of Tanzania increased greatly from 1990 to 2005. At least 563 villagers were attacked and many eaten over this period—a number far exceeding the more famed "Tsavo" incidents of a century earlier. The incidents occurred near Selous National Park in Rufiji District and in Lindi Province near the Mozambican border. While the expansion of villagers into bush country is one concern, the authors argue that conservation policy must mitigate the danger because, in this case, conservation contributes directly to human deaths. Cases in Lindi have been documented where lions seize humans from the center of substantial villages.
Author Robert R. Frump wrote in The Man-eaters of Eden that Mozambican refugees regularly crossing Kruger National Park at night in South Africa are attacked and eaten by the lions; park officials have conceded that man-eating is a problem there. Frump believes thousands may have been killed in the decades after apartheid sealed the park and forced the refugees to cross the park at night. For nearly a century before the border was sealed, Mozambicans had regularly walked across the park in daytime with little harm.
Packer estimates more than 200 Tanzanians are killed each year by lions, crocodiles, elephants, hippos, and snakes, and that the numbers could be double that amount, with lions thought to kill at least 70 of those. Packer and Ikanda are among the few conservationists who believe western conservation efforts must take account of these matters not just because of ethical concerns about human life, but also for the long term success of conservation efforts and lion preservation.
A man-eating lion was killed by game scouts in Southern Tanzania in April 2004. It is believed to have killed and eaten at least 35 people in a series of incidents covering several villages in the Rufiji Delta coastal region. Dr Rolf D. Baldus, the GTZ wildlife programme coordinator, commented that it was likely that the lion preyed on humans because it had a large abscess underneath a molar which was cracked in several places. He further commented that "This lion probably experienced a lot of pain, particularly when it was chewing." GTZ is the German development cooperation agency and has been working with the Tanzanian government on wildlife conservation for nearly two decades. As in other cases this lion was large, lacked a mane, and had a tooth problem.
The "All-Africa" record of man-eating generally is considered to be not Tsavo, but the lesser-known incidents in the late 1930s through the late 1940s in what was then Tanganyika (now Tanzania). George Rushby, game warden and professional hunter, eventually dispatched the pride, which over three generations is thought to have killed and eaten 1,500 to 2,000 in what is now Njombe district.
So, with all this, lion is truly the king of animals.
Hippopotamus
July 13th, 2008
The hippopotamus is semi-aquatic, inhabiting rivers and lakes in sub-Saharan Africa in groups of 5-30 hippos. During the day they remain cool by staying in the water or mud; reproduction and childbirth both occur in water, where territorial bulls preside over a stretch of river. They emerge at dusk to graze on grass. While hippos rest near each other in territories in the water, grazing is a solitary activity and hippos are not territorial on land.
Despite their physical resemblance to pigs and other terrestrial even-toed ungulates, their closest living relatives are cetaceans (whales, porpoise, etc.). The common ancestor of whales and hippos split from other even-toed ungulates around 60 million years ago. The earliest known hippopotamus fossils, belonging to the genus Kenyapotamus in Africa, date to around 16 million years ago.
The hippopotamus is recognizable for its barrel-shaped torso, enormous mouth and teeth, hairless body, stubby legs and tremendous size. It is similar in size to the White Rhinoceros; only elephants are consistently heavier. Despite its stocky shape and short legs, it can easily outrun a human. Hippos have been clocked at 30 mph (48 km/h) while running short distances, faster than an Olympic sprinter. The hippopotamus is regarded to be Africa's most dangerous animal, and is among the most aggressive animals in the world. There are an estimated 125,000 to 150,000 hippos remaining throughout Sub-Saharan Africa, of which Zambia (40,000) and Tanzania (20,000-30,000) have the largest populations. They are still threatened by poaching for their meat and ivory canine teeth, and by habitat loss.
Hippopotamidae are classified along with other even-toed ungulates in the order, Artiodactyla. Other members of Artiodactyla include camels, cows, deer and pigs; although hippopotamuses are not closely related to these species.
As indicated by the name, ancient Greeks considered the hippopotamus to be related to the horse. Until 1985, naturalists grouped hippos with pigs, based on molar patterns. Evidence, first from blood proteins, then from molecular systematics and DNA and the fossil record, show that their closest living relatives are cetaceans—whales, porpoises and the like. Hippopotamuses have more in common with whales than they do with other Artiodactyls (even-toed ungulates), such as pigs, because the common ancestor of hippos and whales branched-off from ruminants and the rest of the even-toed ungulates. Thus, hippos are more closely related to whales than to other members of Artiodactyla. While cetaceans and hippos are each other's closest living relatives, their lineages split soon after their divergence from the rest of the even-toed ungulates.
As many as three species of Malagasy Hippopotamus became extinct during the Holocene on Madagascar, one of them within the past 1,000 years. The Malagasy Hippos were smaller than the modern hippopotamus, likely through the process of insular dwarfism. There is fossil evidence that many Malagasy Hippos were hunted by humans, a likely factor in their eventual extinction. Isolated members of Malagasy Hippopotamus may have survived in remote pockets; in 1976, villagers described a living animal called the Kilopilopitsofy, which may have been a Malagasy Hippopotamus.
A separate species of Hippopotamus, the European Hippopotamus (H. antiquus) and H. gorgops ranged throughout continental Europe and the British Isles. Both species became extinct before the last glaciation. Ancestors of European Hippos, found their way to many islands of the Mediterranean, during the Pleistocene.
These Pleistocene dwarf hippos of the Mediterranean lived on Crete (H. creutzburgi), Cyprus (H. minor), Malta (H. melitensis) and Sicily (H. pentlandi). Of these, the Cyprus Dwarf Hippopotamus, survived until the end of the Pleistocene or early Holocene. Evidence from an archaeological site Aetokremnos, continues to cause debate on whether or not the species encountered, and was driven to extinction, by man.
Hippos spend most of their days wallowing in the water or the mud, with the other members of their pod. The water serves to keep their body temperature cool, and to keep their skin from drying out. With the exception of eating, most of hippopotamuses' lives—from childbirth, fighting with other hippos, and reproduction—occur in the water.
Hippos leave the water at dusk and travel inland, sometimes up to 8 kilometers (5 mi), to graze on short grass, their main source of food. They spend four to five hours grazing and can consume 68 kilograms (150 lb) of grass each night. Like almost any herbivore, they will consume many other plants if presented with them, but their diet in nature consists almost entirely of grass, with only minimal consumption of aquatic plants. Hippos have been spotted eating carrion, usually close to the water. There are other reports of meat-eating, and even cannibalism and predation. The stomach anatomy of a hippo is not suited to carnivory, and meat-eating is likely caused by aberrant behavior or nutritional stress.
The diet of hippos consists mostly of terrestrial grasses, but they spend most of their time in the water. Most of their defecation occurs in the water, creating allochthonous deposits of organic matter along the river beds. These deposits have an unclear ecological function. Because of their size and their habit of taking the same paths to feed, hippos can have a significant impact on the land they walk across, both by keeping the land clear of vegetation and depressing the ground. Over prolonged periods hippos can divert the paths of swamps and channels.
Interestingly, adult hippos can't actually swim and are not generally buoyant. When in deep water, they usually propel themselves by leaps, pushing off from the bottom. They move at speeds up to 8 km/h (5 mph) in water. However, young hippos are buoyant and more often move by swimming—propelling themselves with kicks of their back legs. Adult hippos typically resurface to breathe every 4–6 minutes. The young have to breathe every two to three minutes. The process of surfacing and breathing is automatic, and even a hippo sleeping underwater will rise and breathe without waking. A hippo closes its nostrils when it submerges.
Hippos are very violent tempered animals. Adult hippos are hostile toward crocodiles, which often live in the same pools and rivers as hippos. This is especially so when hippo calves are around. Hippos have been known to be very aggressive towards humans, and it is often claimed that hippos are the deadliest animal in Africa; however, according to Smithsonian Magazine, while the animal is very dangerous, reliable statistics for this are unavailable.
To mark territory, hippos spin their tails while defecating to distribute their excrement over the greatest possible area. Hippos also urinate backwards (are retromingent), likely for the same reason.
Hippos rarely kill each other, even in territorial challenges. Usually a territorial bull and a challenging bachelor will stop fighting when it is clear that one hippo is stronger. When hippos become overpopulated, or when a habitat starts to shrink, bulls will sometimes attempt to kill infants; sometimes female hippos will kill the bulls to protect their infants, but neither behavior is common under normal conditions.
Probably, hippos are not the most beautiful animals, they are rarely friendly, but they attract many people, because there is something special about them, and many love that.
