Biodiversity » Wild Life

Whales

admin — Thu, 26 May 2011 10:41:46 +0000

Kingdom:     Animalia
Phylum:     Chordata
Class:     Mammalia
Subclass:     Eutheria
Order:     Cetacea

Whale is the common name for various marine mammals of the order Cetacea.The term whale sometimes refers to all cetaceans, but more often it excludes dolphins and porpoises,which belong to suborder Odontoceti (toothed whales). This suborder also includes the sperm whale, killer whale, pilot whale, and beluga whale. The other Cetacean suborder Mysticeti (baleen whales), are filter feeders that eat small organisms caught by straining seawater through a comblike structure found in the mouth called baleen. This suborder includes the blue whale, the humpback whale, the bowhead whale and the minke whale. All Cetacea have forelimbs modified as fins, a tail with horizontal flukes, and nasal openings (blowholes) on top of the head.
Whales range in size from the blue whale, the largest animal known to have ever existed at 35 m (115 ft) and 136 tonnes (134 LT; 150 ST), to various pygmy species, such as the pygmy sperm whale at 3.5 m (11 ft).
Whales collectively inhabit all the world’s oceans and number in the millions, with annual population growth rate estimates for various species ranging from 3-13%.For centuries, whales have been hunted for meat and as a source of raw materials. By the middle of the 20th century, however, industrial whaling had left many species seriously endangered, leading to the end of whaling in all but a few countries.

Cetaceans are divided into two suborders:
The largest suborder, Mysticeti (baleen whales) are characterized by baleen, a sieve-like structure in the upper jaw made of keratin, which it uses to filter plankton from the water.
Odontoceti (toothed whales) bear sharp teeth for hunting. Odontoceti also include dolphins and porpoises.
Both cetaceans and artiodactyl are now classified under the super-order Cetartiodactyla which includes both whales and hippopotamuses. Whales are the hippopotamus’s closest living relatives.
All cetaceans, including whales, dolphins and porpoises, are descendants of land-living mammals of the Artiodactyl order (even-toed ungulates). Both descended from a common ancestor, the Indohyus (an extinct semi-aquatic deer-like ungulate) from which they split around 54 million years ago.Primitive whales probably first took to the sea about 50 million years ago and became fully aquatic about 5-10 million years later.
Anatomy
Like all mammals, whales breathe air, are warm-blooded, nurse their young with milk from mammary glands, and have body hair.
Beneath the skin lies a layer of fat called blubber, which stores energy and insulates the body. Whales have a spinal column, a vestigial pelvic bone, and a four-chambered heart. The neck vertebrae are typically fused, trading flexibility for stability during swimming.
Blowhole(s)
Whales breathe via blowholes; baleen whales have two and toothed whales have one. These are located on the top of the head, allowing the animal to remain mostly submerged whilst breathing. Breathing involves expelling excess water from the blowhole, forming an upward spout, followed by inhaling air into the lungs. Spout shapes differ among species and can help with identification.
Appendages
The body shape is fusiform and the modified forelimbs, or fins, are paddle-shaped. The end of the tail is composed of two flukes, which propel the animal by vertical movement, as opposed to the horizontal movement of a fish tail. Although whales do not possess fully developed hind limbs, some (such as sperm whales and baleen whales) possess discrete rudimentary appendages, which may even have feet and digits. Most species have a dorsal fin.
Dentition
Toothed whales, such as the sperm whale, possess teeth with cementum cells overlying dentine cells. Unlike human teeth, which are composed mostly of enamel on the portion of the tooth outside of the gum, whale teeth have cementum outside the gum. Only in larger whales, where the cementum has been worn away on the tip of the tooth, does enamel show.
Instead of teeth, Baleen whales have a row of plates on the upper side of their jaws that resemble the “teeth” of a comb.
Ears
The whale ear has specific adaptations to the marine environment. In humans, the middle ear works as an impedance matcher between the outside air’s low impedance and the cochlear fluid’s high impedance. In aquatic mammals such as whales, however, there is no great difference between the outer and inner environments. Instead of sound passing through the outer ear to the middle ear, whales receive sound through the throat, from which it passes through a low-impedance fat-filled cavity to the inner ear.
Reproduction
Males are called ‘bulls’, females, ‘cows’ and newborns, ‘calves’. Most species do not maintain fixed partnerships and females have several mates each season.
The female delivers usually a single calf tail-first to minimize the risk of drowning. Whale cows nurse by actively squirting milk, so fatty that it has the consistency of toothpaste, into the mouths of their young.Nursing continues for more than a year in many species, and is associated with a strong bond between mother and calf. Reproductive maturity occurs typically at seven to ten years. This mode of reproduction produces few offspring, but increases survival probability.
Lifespan
Whale lifespans vary among species and are not well characterized. Whaling left few older individuals to observe directly. R.M. Nowak of Johns Hopkins University estimated that humpback whales may live as long as 77 years.In 2007, a 19th century lance fragment was found in a bowhead whale off Alaska, suggesting the individual could be between 115 and 130 years old.Aspartic acid racemization in the whale eye, combined with a harpoon fragment, indicated an age of 211 years for another male, which, if true would make bowheads the longest-lived extant mammal species.The accuracy of this technique has been questioned because racemization did not correlate well with other dating methods.

[Show as slideshow]

Pilot Whale
Pilot Whales use a unique torpedo-like dive technique to hunt their prey. This behavior has given them the nickname “cheetah of the deep.”
Pilot Whales can swim about 20 miles per hour and maintain that speed for up to 200 meters (650 feet).
Pilot Whales can be found just about anywhere. In fact, Pilot Whales are believed to be the most distributed whale in the World.
Although Pilot Whales are located just about everywhere, don’t count on seeing them very often because they tend to stay in deeper waters.
Pilot Whales have a relatively small appetite. They only eat about 30 pounds of food daily, which is not very much compared to other types of whales their size.
Pilot Whales love to eat squid, but they also eat other types of sea creatures such as fish and octopus.
Some Pilot Whale mothers have been known to nurse their young for as many as ten years. Though, most Pilot Whale mothers nurse their young for about two years.
Pilot Whales love to stick together. They often swim together in large groups, somtimes consisting of up to 100 whales.
Pilot Whales got the name ‘pilot’ because it was originally believed that Pilot Whale pods were herded by a “leader whale.”
Beaked Whale
Beaked Whales are one of the world’s most sophisticated and least understood mammals.
Beaked Whales dive to depths of up to 2000 meters looking for food.
Beaked Whales primarily eat squid and deep water fish.
Beaked Whales use sonar, much like dolphins, to hunt for their prey.
Beaked Whales tend to travel alone or in small groups.
Beaked Whales can hold their breath while diving for as much as 40 minutes.
There are 21 different species of Beaked Whales identified in the world.
Beaked Whales suck food into their mouth like a vacuum instead of biting their prey.
Beaked Whales range from 4 to 13 meters in length and weigh from 1 to 15 tons.
The total number of Beaked Whales in the world is largely unknown because they are so rarely seen by man.
Killer Whale
Killer Whales can travel up to 30 miles per hour, making them one of the fastest creatures in the sea.
Killer Whales have very large appetites, eating up to 5 percent of their body weight each day.
Killer Whales can dive deep underwater by controlling their need for oxygen through limiting the flow of blood to their hearts and brains.
Although Killer Whales have the fearsome name “killer,” they actually don’t eat people. Rather, they eat dolphins and smaller whales.
Killer Whales prefer to live in oceans with cooler waters; however, they can be found in all the World’s oceans.
Killer Whales do not breed with relatives. They only breed with Killer Whales that are not closely related to them within their own pods.
Killer Whales use vocal sounds to communicate with each other.
Every Killer Whale pod has its own unique “accent,” making it easy for them to identify Killer Whales that are part of the same pod.
Although Killer Whales are not smarter than humans, their brain is five times larger than the human brain. Nonetheless, Killer Whales are very social, intelligent, and curious creatures.
Every Killer Whale has a mark behind its dorsal fin that is completely unique. Think of it as a fingerprint, except for whales.
Killer whale is in the Dolphin family.In fact, it is the largest dolphin. The Killer Whale is also one of the most easily recognized whales because of its black and white coloration.
Humpback whale
Humpback whales are known for their magical songs, which travel for great distances through the world’s oceans. These sequences of moans, howls, cries, and other noises are quite complex and often continue for hours on end. Scientists are studying these sounds to decipher their meaning. It is most likely that humpbacks sing to communicate with others and to attract potential mates.
These whales are found near coastlines, feeding on tiny shrimp-like krill, plankton, and small fish. Humpbacks migrate annually from summer feeding grounds near the poles to warmer winter breeding waters closer to the Equator. Mothers and their young swim close together, often touching one another with their flippers with what appear to be gestures of affection. Females nurse their calves for almost a year, though it takes far longer than that for a humpback whale to reach full adulthood. Calves do not stop growing until they are ten years old.
Humpbacks are powerful swimmers, and they use their massive tail fin, called a fluke, to propel themselves through the water and sometimes completely out of it. These whales, like others, regularly leap from the water, landing with a tremendous splash. Scientists aren’t sure if this breaching behavior serves some purpose, such as cleaning pests from the whale’s skin, or whether whales simply do it for fun.
Beluga whales
Belugas are also called white whales, and their unusual color makes them one of the most familiar and easily distinguishable of all the whales. Calves are born gray or even brown and only fade to white as they become sexually mature around five years of age.
White whales are smallish, ranging from 13 to 20 feet (4 to 6.1 meters) in length. They have rounded foreheads and no dorsal fin.
Belugas generally live together in small groups known as pods. They are social animals and very vocal communicators that employ a diversified language of clicks, whistles, and clangs. Belugas can also mimic a variety of other sounds.
These whales are common in the Arctic Ocean’s coastal waters, though they are found in subarctic waters as well. Arctic belugas migrate southward in large herds when the sea freezes over. Animals trapped by Arctic ice often die, and they are prey for polar bears, killer whales, and for Arctic people. They are hunted by indigenous people of the north, and by commercial fisheries that brought some populations, such as those in the Gulf of St. Lawrence, to near collapse.
Beluga feed on fish, crustaceans, and worms. The whale is related to the tusked “unicorn” whale known as the narwhal. The beluga is not related to the sturgeon of the same name, which has been heavily fished for its famous caviar.
Blue whales
Blue whales are the largest animals ever known to have lived on Earth. These magnificent marine mammals rule the oceans at up to 100 feet (30 meters) long and upwards of 200 tons (181 metric tons). Their tongues alone can weigh as much as an elephant. Their hearts, as much as an automobile.
Blue whales reach these mind-boggling dimensions on a diet composed nearly exclusively of tiny shrimplike animals called krill. During certain times of the year, a single adult blue whale consumes about 4 tons (3.6 metric tons) of krill a day.
Blue whales are baleen whales, which means they have fringed plates of fingernail-like material, called baleen, attached to their upper jaws. The giant animals feed by first gulping an enormous mouthful of water, expanding the pleated skin on their throat and belly to take it in. Then the whale’s massive tongue forces the water out through the thin, overlapping baleen plates. Thousands of krill are left behind—and then swallowed.
Blue whales look true blue underwater, but on the surface their coloring is more a mottled blue-gray. Their underbellies take on a yellowish hue from the millions of microorganisms that take up residence in their skin. The blue whale has a broad, flat head and a long, tapered body that ends in wide, triangular flukes.
Blue whales live in all the world’s oceans occasionally swimming in small groups but usually alone or in pairs. They often spend summers feeding in polar waters and undertake lengthy migrations towards the Equator as winter arrives.
These graceful swimmers cruise the ocean at more than five miles an hour (eight kilometers an hour), but accelerate to more than 20 miles an hour (32 kilometers an hour) when they are agitated. Blue whales are among the loudest animals on the planet. They emit a series of pulses, groans, and moans, and it’s thought that, in good conditions, blue whales can hear each other up to 1,000 miles (1,600 kilometers) away. Scientists think they use these vocalizations not only to communicate, but, along with their excellent hearing, to sonar-navigate the lightless ocean depths.
Really Big Babies
Blue whale calves enter the world already ranking among the planet’s largest creatures. After about a year inside its mother’s womb, a baby blue whale emerges weighing up to 3 tons (2.7 metric tons) and stretching to 25 feet (8 meters). It gorges on nothing but mother’s milk and gains about 200 pounds (91 kilograms) every day for its first year.
Blue whales are among Earth’s longest-lived animals. Scientists have discovered that by counting the layers of a deceased whale’s waxlike earplugs, they can get a close estimate of the animal’s age. The oldest blue whale found using this method was determined to be around 110 years old. Average lifespan is estimated at around 80 to 90 years.
Between 10,000 and 25,000 blue whales are believed to still swim the world’s oceans. Aggressive hunting in the 1900s by whalers seeking whale oil drove them to the brink of extinction. Between 1900 and the mid-1960s, some 360,000 blue whales were slaughtered. They finally came under protection with the 1966 International Whaling Commission, but they’ve managed only a minor recovery since then.
Blue whales have few predators but are known to fall victim to attacks by sharks and killer whales, and many are injured or die each year from impacts with large ships. Blue whales are currently classified as endangered on the World Conservation Union (IUCN) Red List.
Gray whales
Gray whales are often covered with parasites and other organisms that make their snouts and backs look like a crusty ocean rock.
The whale uses its snout to forage by dislodging tiny creatures from the seafloor. It then filters these morsels with its baleen—a comblike strainer of plates in the upper jaw. A piece of gray whale baleen, also called whalebone, is about 18 inches (46 centimeters) long and has a consistency much like a fingernail. Whalebone was once used to make ladies’ corsets and umbrella ribs.
The gray whale is one of the animal kingdom’s great migrators. Traveling in groups called pods, some of these giants swim 12,430 miles (20,000 kilometers) round-trip from their summer home in Alaskan waters to the warmer waters off the Mexican coast. The whales winter and breed in the shallow southern waters and balmier climate. Other gray whales live in the seas near Korea.
Like all whales, gray whales surface to breathe, so migrating groups are often spotted from North America’s west coast. These whales were once the target of extensive hunting, and by early in the 20th century they were in serious danger of extinction.
Today gray whales are protected by international law, and their numbers have grown. In 1994, the gray whale was removed from the United States endangered species list.
Right whales
Right whales are the rarest of all large whales. There are several species, but all are identified by enormous heads, which can measure up to one-third of their total body length. These whales’ massive heads and jaws accommodate hundreds of baleen “teeth.” Rights and other baleen-feeding whales use a comblike strainer of baleen plates and bristles to ensnare tiny morsels of food as they swim. Right whales feed on zooplankton and other tiny organisms using baleens up to 8 feet (2.4 meters) long.
southern and the two species of northern right whales live in temperate Atlantic or Pacific waters, often near the coast.
Right whales were named by whalers who identified them as the “right” whale to kill on a hunt. These leviathans had enormous value for their plentiful oil and baleen, which were used for corsets, buggy whips, and other contrivances. Because of their thick blubber, right whales also float accommodatingly after they have been killed. Populations of these whales were decimated during the whaling heydays of the 17th, 18th, and 19th centuries. During this period they came close to extinction.
Because females do not become sexually mature until ten years of age and give birth to a single calf after a yearlong pregnancy, populations grow slowly.
All species of right whales are endangered and have enjoyed complete international protection since 1949. Several thousand southern right whales are believed to survive, and they have shown some encouraging population growth since their protection. South Africa’s population is believed to have grown from 100 to 1,000 animals since 1940.
Northern right whales are the most endangered of all large whales. They number only several hundred, and populations do not appear to have grown in the decades since their protection began.
Sperm whales
Sperm whales are easily recognized by their massive heads and prominent rounded foreheads. They have the largest brain of any creature known to have lived on Earth. Their heads also hold large quantities of a substance called spermaceti. Whalers once believed that the oily fluid was sperm, but scientists still do not understand the function of spermaceti. One common theory is that the fluid—which hardens to wax when cold—helps the whale alter its buoyancy so it can dive deep and rise again. Sperm whales are known to dive as deep as 3,280 feet (1,000 meters) in search of squid to eat. These giant mammals must hold their breath for up to 90 minutes on such dives.
These toothed whales eat thousands of pounds of fish and squid—about one ton (907 kg) per day.
Sperm whales are often spotted in groups (called pods) of some 15 to 20 animals. Pods include females and their young, while males may roam solo or move from group to group. Females and calves remain in tropical or subtropical waters all year long, and apparently practice communal childcare. Males migrate to higher latitudes, alone or in groups, and head back towards the equator to breed. Driven by their tale fluke, approximately 16 feet (5 meters) from tip to tip, they can cruise the oceans at around 23 miles (37 kilometers) per hour.
These popular leviathans are vocal and emit a series of “clangs” that may be used for communication or for echolocation. Animals that use echolocation emit sounds that travel underwater until they encounter objects, then bounce back to their senders—revealing the location, size, and shape of their target.
Sperm whales were mainstays of whaling’s 18th and 19th century heyday. A mythical albino sperm whale was immortalized in Herman Melville’s Moby Dick, though Ahab’s nemesis was apparently based on a real animal whalers called Mocha Dick. The animals were targeted for oil and ambergris, a substance that forms around squid beaks in a whale’s stomach. Ambergris was (and remains) a very valuable substance once used in perfumes.
Despite large population drops due to whaling, sperm whales are still fairly numerous.
Narwhale
The narwhal is the unicorn of the sea, a pale-colored porpoise found in Arctic coastal waters and rivers. These legendary animals have two teeth. In males, the more prominent tooth grows into a swordlike, spiral tusk up to 8.8 feet (2.7 meters) long. The ivory tusk tooth grows right through the narwhal’s upper lip. Scientists are not certain of the tusk’s purpose, but some believe it is prominent in mating rituals, perhaps used to impress females or to battle rival suitors. Females sometimes grow a small tusk of their own, but it does not become as prominent as the male’s.

Narwhals are related to bottlenose dolphins, belugas, harbor porpoises, and orcas. Like some other porpoises, they travel in groups and feed on fish, shrimp, squid, and other aquatic fare. They are often sighted swimming in groups of 15 to 20, but gatherings of hundreds—or even several thousand—narwhals have been reported. Sometimes these groups become trapped by shifting pack ice and fall victim to Inuit hunters, polar bears, or walruses.
people hunt the narwhal for their long tusks and their skin, an important source of vitamin C in the traditional Arctic diet.

Wild Dog

admin — Fri, 20 May 2011 16:54:43 +0000

Taxonomy

Order – Carnivora
Family – Canidae
Genus – Lycaon
Species – Lycaon pictus

Sometimes called hunting-dogs, wild dogs are found in packs of between five and twenty or more. They have good eyesight and tend to prefer open country and hunt during daylight.

The wild dog has long slender legs and a lean body – advantages to any predator which depends on its running ability to catch its prey. Their large, rounded ears are very distinctive, as is their blotched or mottled body coloration, generally a mixture of black, orange-brown and white.

Nomadic for much of the year, wild dogs will roam over very large areas, constantly searching for prey to satisfy their almost continuous hunger. Once the pack has chosen its next kill they hunt down the victim with dogged persistence and matchless stamina. They will chase their prey, sometimes for great distances, and once their prey is down, either from exhaustion or the extent of maiming, death is very quick.

1-7 pups are born in the dry season, after a short gestation period of 2-3 months. The young are well looked after by the pack. The young start hunting with the pack when they are 2-3 months old. They are also the first to eat on a kill.

Blue Wildebeest

admin — Fri, 20 May 2011 16:51:21 +0000

Taxonomy

Order – Artiodactyla
Family – Bovidae
Sub Family – Alcelaphinae
Genus – Connochaetes
Species – Connochaetes taurinus

Wildebeest prefer open plains. This habitat makes it easier for them to detect potential predators such as lion, but also enables them to run more effectively.

Wildebeest are sociable, and often form smaller herds of around four to eight animals. They need frequent access to water and will migrate to fresh grazing areas where they feed on the short tufts of grass. Sometimes these migrations can be in larger herds, as seen in the Serengeti.

Both sexes have broad horns which project sideways and then curve upwards, tapering to a sharp point, similar to those of the buffalo. Blue Wildebeest have lean bodies with long thin legs and broad necks. They are uniform grayish-black in colour, patterned with indistinct vertical stripes.

During the breeding season, females form calving herds and give birth to a single calf within few days of each other. The calf is able to stand a few minutes after being born, and within a day, the calf can run fast enough to keep up with the herd.

Burchell’s Zebra

admin — Fri, 20 May 2011 16:42:26 +0000

Taxonomy

Order – Perissodactyla
Family – Equidae
Genus – Equus
Species – Equus burchelli

The Burchell’s Zebra is found in grassland savanna regions. They are sociable animals generally seen in herds of anything from a few Zebra to a few hundred and they are commonly seen grazing with wildebeest and other sociable species. Large herds of Zebra are made up of smaller family units composed of a stallion, several mares and their youngsters. Good grazing and availability of water are important habitat requirements and a herd will migrate to a better area if this is lacking.

Burchell’s Zebras are differentiated from other zebra species by the light brown ‘shadow-stripes’ found between the black stripes, the black tufted tail and the black patch around its nostril.

Lions are the Zebra’s main predator with new born zebra foals being most vulnerable to attack. A single foul is born after a gestation period of 12 months, usually during July to September.

Aardwolf

admin — Fri, 20 May 2011 16:30:58 +0000

Taxonomy

Order – Carnivora
Family – Hyaenidae
Genus – Proteles
Species – Proteles cristatus

The Aardwolf’s habitat includes open patches around pans and grassy plains. Its distribution is dictated by the availability of termites, which is its principal food. Their diet is almost entirely insects. They eat no meat, as their teeth are ill-adapted to tougher foods.
The Aardwolf is about the size of a small jackal and resembles a hyena in over all shape. It’s yellow-brown to dull yellow, long and coarse fur, has distinct vertical black stripes on the flanks and some on the legs. The long hair down the neck and back is raised only when the animal is frightened or threatened. The muzzle and feet are black, and the ears are long, narrow and pointed.
The Aardwolf is a solitary animals and occasionally observed in family parties of four or five. They are nocturnal animals, sleeping or hiding in old Antbear holes, or holes which they dig themselves. Droppings are usually deposited at a number of latrine sites within the home range and grass-stalks are marked with a secretion from the anal glands.
Their defence consists of using their long canine teeth and if necessary, they bristle their manes, which makes them appear much longer, especially in the dark.
Litters of 2-4 young are born from September to April after a gestation period of ±2 months. Births are usually during the summer months. They are born in a burrow and if the mother is disturbed, she may move the cubs, carrying them by the scruff of their necks, to a new den.

Lion

admin — Tue, 17 May 2011 18:56:49 +0000

Scientific classification

Kingdom:Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Felidae
Genus: Panthera
Species: P. leo
Binomial name: Panthera leo (Linnaeus, 1758)

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, 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. 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. 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.Lions live for ten to fourteen years in the wild, while in captivity they can live longer than twenty years.

[Show as slideshow]

In the wild, males seldom live longer than ten years, as injuries sustained from continual fighting with rival males greatly reduce their longevity. 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.

Highly distinctive, the male lion is easily recognised by its mane, and its face is one of the most widely recognised animal symbols in human culture. Depictions have existed from the Upper Paleolithic period, with carvings and paintings from the Lascaux and Chauvet Caves, through virtually all ancient and medieval cultures where they once occurred. It has been extensively depicted in sculptures, in paintings, on national flags, and in contemporary films and literature. Lions have been kept in menageries since the time of the Roman Empire and have been a key species sought for exhibition in zoos the world over since the late eighteenth century. Zoos are cooperating worldwide in breeding programs for the endangered Asiatic subspecies.