The dodo (Raphus cucullatus) is an extinct flightless bird that was endemic to the island of Mauritius, east of Madagascar in the Indian Ocean. The dodo's closest genetic relative was the also-extinct Rodrigues solitaire, the two forming the subfamily Raphinae of the family of pigeons and doves. The closest living relative of the dodo is the Nicobar pigeon. A white dodo was once thought to have existed on the nearby island of Réunion, but this is now thought to have been confusion based on the Réunion ibis and paintings of white dodos.

Subfossil remains show the dodo was about 1 metre (3 ft 3 in) tall and may have weighed 10.6–17.5 kg (23–39 lb) in the wild. The dodo's appearance in life is evidenced only by drawings, paintings, and written accounts from the 17th century. As these vary considerably, and only some of the illustrations are known to have been drawn from live specimens, its exact appearance in life remains unresolved, and little is known about its behaviour. Though the dodo has historically been considered fat and clumsy, it is now thought to have been well-adapted for its ecosystem. It has been depicted with brownish-grey plumage, yellow feet, a tuft of tail feathers, a grey, naked head, and a black, yellow, and green beak. It used gizzard stones to help digest its food, which is thought to have included fruits, and its main habitat is believed to have been the woods in the drier coastal areas of Mauritius. One account states its clutch consisted of a single egg. It is presumed that the dodo became flightless because of the ready availability of abundant food sources and a relative absence of predators on Mauritius.

The first recorded mention of the dodo was by Dutch sailors in 1598. In the following years, the bird was hunted by sailors and invasive species, while its habitat was being destroyed. The last widely accepted sighting of a dodo was in 1662. Its extinction was not immediately noticed, and some considered it to be a mythical creature. In the 19th century, research was conducted on a small quantity of remains of four specimens that had been brought to Europe in the early 17th century. Among these is a dried head, the only soft tissue of the dodo that remains today. Since then, a large amount of subfossil material has been collected on Mauritius, mostly from the Mare aux Songes swamp. The extinction of the dodo within less than a century of its discovery called attention to the previously unrecognised problem of human involvement in the disappearance of entire species. The dodo achieved widespread recognition from its role in the story of Alice's Adventures in Wonderland, and it has since become a fixture in popular culture, often as a symbol of extinction and obsolescence. Throughout the 19th century, several species were classified as congeneric with the dodo, including the Rodrigues solitaire and the Réunion solitaire, as Didus solitarius and Raphus solitarius, respectively (Didus and Raphus being names for the dodo genus used by different authors of the time). An atypical 17th-century description of a dodo and bones found on Rodrigues, now known to have belonged to the Rodrigues solitaire, led Abraham Dee Bartlett to name a new species, Didus nazarenus, in 1852.[6] Based on solitaire remains, it is now a synonym of that species.[7] Crude drawings of the red rail of Mauritius were also misinterpreted as dodo species; Didus broeckii and Didus herberti. Click here to READ MORE..!!

The great auk (Pinguinus impennis) is a species of flightless alcid that became extinct in the mid-19th century. It was the only modern species in the genus Pinguinus. It is not closely related to the birds now known as penguins, which were discovered later and so named by sailors because of their physical resemblance to the great auk.

It bred on rocky, isolated islands with easy access to the ocean and a plentiful food supply, a rarity in nature that provided only a few breeding sites for the great auks. When not breeding, they spent their time foraging in the waters of the North Atlantic, ranging as far south as northern Spain and along the coastlines of Canada, Greenland, Iceland, the Faroe Islands, Norway, Ireland, and Great Britain.

The great auk was 75 to 85 cm (30 to 33 in) tall and weighed about 5 kg (11 lb), making it the largest alcid to survive into the modern era, and the second-largest member of the alcid family overall (the prehistoric Miomancalla was larger).[5] It had a black back and a white belly. The black beak was heavy and hooked, with grooves on its surface. During summer, great auk plumage showed a white patch over each eye. During winter, the great auk lost these patches, instead developing a white band stretching between the eyes. The wings were only 15 cm (5.9 in) long, rendering the bird flightless. Instead, the great auk was a powerful swimmer, a trait that it used in hunting. Its favourite prey were fish, including Atlantic menhaden and capelin, and crustaceans. Although agile in the water, it was clumsy on land. Great auk pairs mated for life. They nested in extremely dense and social colonies, laying one egg on bare rock. The egg was white with variable brown marbling. Both parents participated in the incubation of the egg for around 6 weeks before the young hatched. The young left the nest site after 2–3 weeks, although the parents continued to care for it.

The great auk was an important part of many Native American cultures, both as a food source and as a symbolic item. Many Maritime Archaic people were buried with great auk bones. One burial discovered included someone covered by more than 200 great auk beaks, which are presumed to be the remnants of a cloak made of great auk skins. Early European explorers to the Americas used the great auk as a convenient food source or as fishing bait, reducing its numbers. The bird's down was in high demand in Europe, a factor that largely eliminated the European populations by the mid-16th century. Scientists soon began to realize that the great auk was disappearing and it became the beneficiary of many early environmental laws, but this proved ineffectual.

Its growing rarity increased interest from European museums and private collectors in obtaining skins and eggs of the bird. On 3 June 1844, the last two confirmed specimens were killed on Eldey, off the coast of Iceland, ending the last known breeding attempt. Later reports of roaming individuals being seen or caught are unconfirmed. A record of one great auk in 1852 is considered by some to be the last sighting of a member of the species. The great auk is mentioned in several novels and the scientific journal of the American Ornithologists' Union is named The Auk in honour of this bird. Click here to READ MORE..!!

Steller's sea cows grew to be 8 to 9 m (26 to 30 ft) long as adults, much larger than extant sirenians.[6] Georg Steller's writings contain two contradictory estimates of weight: 4 and 24.3 t (4.4 and 26.8 short tons). The true value is estimated to fall between these figures, at about 8–10 t (8.8–11.0 short tons).[7] This size made the sea cow one of the largest mammals of the Holocene epoch, along with whales,[8] and was likely an adaptation to reduce its surface area-to-volume ratio and conserve heat.[9]

Unlike other sirenians, Steller's sea cow was positively buoyant, meaning that it was unable to completely submerge. It had a very thick outer skin, 2.5 cm (1 in), to prevent injury from sharp rocks and ice and possibly to prevent unsubmerged skin from drying out.[6][10] The sea cow's blubber was 8–10 cm (3–4 in) thick, another adaptation to the frigid climate of the Bering Sea.[11] Its skin was brownish-black, with white patches on some individuals. It was smooth along its back and rough on its sides, with crater-like depressions most likely caused by parasites. This rough texture led to the animal being nicknamed the "bark animal". Hair on its body was sparse, but the insides of the sea cow's flippers were covered in bristles.[5] The fore limbs were roughly 67 cm (26 in) long, and the tail fluke was forked.[5]

The sea cow's head was small and short in comparison to its huge body. The animal's upper lip was large and broad, extending so far beyond the lower jaw that the mouth appeared to be located underneath the skull. Unlike other sirenians, Steller's sea cow was toothless and instead had a dense array of interlacing white bristles on its upper lip. The bristles were about 3.8 cm (1.5 in) in length and were used to tear seaweed stalks and hold food.[5] The sea cow also had two keratinous plates located on its palate and mandible, used for chewing.[12] According to Steller, these plates (or "masticatory pads") were held together by interdental papillae, a part of the gums, and had many small holes containing nerves and arteries.[5] Side view of a brown-green dugong: It is similar to a manatee in that the head is pointed downwards, the eyes are small, and the body is stocky. The arms are perpendicular to the body and bend backwards toward the tail. There are no fingernails. The tail is knotched, much like a dolphin tail. Model in the Natural History Museum of London

As with all sirenians, the sea cow's snout pointed downwards, which allowed it to better grasp kelp. The sea cow's nostrils were roughly 5 cm (2 in) long and wide. In addition to those within its mouth, the sea cow also had stiff bristles 10–12.7 cm (3.9–5.0 in) long protruding from its muzzle.[9][5] Steller's sea cow had small eyes located halfway between its nostrils and ears with black irises, livid eyeballs, and canthi which were not externally visible. The animal had no eyelashes, but like other diving creatures such as sea otters, Steller's sea cow had a nictitating membrane, which covered its eyes to prevent injury while feeding. The tongue was small and remained in the back of the mouth, unable to reach the masticatory (chewing) pads.[9][5]

The sea cow's spine is believed to have had seven cervical (neck), 17 thoracic, three lumbar, and 34 caudal (tail) vertebrae. Its ribs were large, with five of 17 pairs making contact with the sternum; it had no clavicles.[5] As in all sirenians, the scapula of Steller's sea cow was fan-shaped, being larger on the posterior side and narrower towards the neck. The anterior border of the scapula was nearly straight, whereas those of modern sirenians are curved. Like other sirenians, the bones of Steller's sea cow were pachyosteosclerotic, meaning they were both bulky (pachyostotic) and dense (osteosclerotic).[9][13] In all collected skeletons of the sea cow, the manus is missing; since Dusisiren—the sister taxon of Hydrodamalis—had reduced phalanges (finger bones), Steller's sea cow possibly did not have a manus at all. Click here to READ MORE..!!

The African buffalo or Cape buffalo (Syncerus caffer) is a large Sub-Saharan African bovine.[2] Syncerus caffer caffer, the Cape buffalo, is the typical subspecies, and the largest one, found in Southern and East Africa. S. c. nanus (African forest buffalo) is the smallest subspecies, common in forest areas of Central and West Africa, while S. c. brachyceros is in West Africa and S. c. aequinoctialis is in the savannas of East Africa. The adult buffalo's horns are its characteristic feature: they have fused bases, forming a continuous bone shield across the top of the head referred to as a "boss". They are widely regarded as among the most dangerous animals on the African continent, and according to some estimates they gore, trample, and kill over 200 people every year.

The African buffalo is not an ancestor of domestic cattle and is only distantly related to other larger bovines. Its unpredictable temperament means that the African buffalo has never been domesticated, unlike its Asian counterpart, the water buffalo. African Cape buffaloes have few predators aside from lions and large crocodiles. As a member of the big five game, the Cape buffalo is a sought-after trophy in hunting.

The African buffalo is a very robust species. Its shoulder height can range from 1.0 to 1.7 m (3.3 to 5.6 ft) and its head-and-body length can range from 1.7 to 3.4 m (5.6 to 11.2 ft). Compared with other large bovids, it has a long but stocky body (the body length can exceed the wild water buffalo, which is heavier and taller) and short but thickset legs, resulting in a relatively short standing height. The tail can range from 70 to 110 cm (28 to 43 in) long. Savannah-type buffaloes weigh 500 to 1,000 kg (1,100 to 2,200 lb), with males normally larger than females, reaching the upper weight range.[3] In comparison, forest-type buffaloes, at 250 to 450 kg (600 to 1,000 lb), are only half that size.[4][5] Its head is carried low; its top is located below the backline. The front hooves of the buffalo are wider than the rear, which is associated with the need to support the weight of the front part of the body, which is heavier and more powerful than the back.

Old bulls often have whitish circles around their eyes and on their face. Females tend to have more-reddish coats. Forest-type buffaloes are 30-40% smaller, reddish brown in colour, with much more hair growth around the ears and with horns that curve back and slightly up. Calves of both types have red coats.

A characteristic feature of the horns of adult male African buffalo (Southern and Eastern populations) is that the bases come very close together, forming a shield referred to as a "boss". From the base, the horns diverge downwards, then smoothly curve upwards and outwards and in some cases inwards and or backwards. In large bulls, the distance between the ends of the horns can reach upwards of one metre (the record being 64.5 inches 164 cm). The horns form fully when the animal reaches the age of five or six years but the bosses do not become "hard" till 8 to 9 years old. In cows, the horns are, on average, 10–20% smaller, and they do not have a boss. Forest buffalo horns are smaller than those of the savanna buffalo from Southern and Eastern Africa, usually measuring less than 40 centimetres (16 in), and are almost never fused. Click here to READ MORE..!!

Cone snails, cone shells, or cones are common names for a large group of small- to large-sized extremely venomous predatory sea snails, marine gastropod molluscs.[1]

Until fairly recently, over 600 species of cone snails were all classified under one genus, Conus, in one family, the Conidae. However, in recent years, it was suggested that cone snails should occupy only a subfamily that should be split into a very large number of genera. A 2014 paper attempted to stabilize a newer classification of the group, significantly reducing the number of new genera but keeping a fairly large number of subgenera. Although the taxonomy has changed significantly several times during recent years, in the current (2015) version of the taxonomy of these snails and their close relatives, cone snails once again compose the entire family Conidae.

Geologically speaking, fossils of cone snails are known from the Eocene to the Holocene epochs.[2] Cone snail species have shells that are shaped more or less like geometric cones. Many species have colorful patterning on the shell surface.[3] Cone snails are almost all tropical in distribution.

Because all cone snails are venomous and capable of "stinging" humans, live ones should never be handled, as their venomous sting will occur without warning and can be fatal. The species most dangerous to humans are the larger cones, which prey on small bottom-dwelling fish; the smaller species mostly hunt and eat marine worms. Cone snails use a hypodermic needle–like modified radula tooth and a venom gland to attack and paralyze their prey before engulfing it. The tooth, which is sometimes likened to a dart or a harpoon, is barbed and can be extended some distance out from the head of the snail, at the end of the proboscis.

Cone snail venoms are mainly peptides. The venoms contain many different toxins that vary in their effects; some are extremely toxic. The sting of small cones is no worse than a bee sting, but the sting of a few of the larger species of tropical cone snails can be serious, occasionally even fatal to humans. Cone snail venom is showing great promise as a source of new, medically important substances.

There are over 800 different species of cone snails.[6] Cone snails are typically found in warm and tropical seas and oceans worldwide, and they reach their greatest diversity in the Western Indo-Pacific region. However, some species are adapted to temperate environments, such as the Cape coast of South Africa,[7][8] the Mediterranean,[9] or the cool waters of southern California (Conus californicus),[10] and are endemic to these areas. Cone snails are found in all tropical and subtropical seas, from the intertidal zone to deeper areas, living on sand or among rocks or coral reefs. When living on sand, these snails bury themselves with only the siphon protruding from the surface. Many tropical cone snails live in or near coral reefs. Some species are found under rocks in the lower intertidal and shallow subtidal zones. Click here to READ MORE..!!

The medusa form of a box jellyfish has a squarish, box-like bell, from which its name is derived. From each of the four lower corners of this hangs a short pedalium or stalk which bears one or more long, slender, hollow tentacles. The rim of the bell is folded inwards to form a shelf known as a velarium which restricts the bell's aperture and creates a powerful jet when the bell pulsates.[7] As a result, box jellyfish can move more rapidly than other jellyfish; speeds of up to 6 metres (20 ft) per minute have been recorded.[8]

In the center of the underside of the bell is a mobile appendage called the manubrium which somewhat resembles an elephant's trunk. At its tip is the mouth. The interior of the bell is known as the gastrovascular cavity. It is divided by four equidistant septa into a central stomach and four gastric pockets. The eight gonads are located in pairs on either side of the four septa. The margins of the septa bear bundles of small gastric filaments which house nematocysts and digestive glands and help to subdue prey. Each septum is extended into a septal funnel that opens onto the oral surface and facilitates the flow of fluid into and out of the animal.[7]

The box jellyfish's nervous system is more developed than that of many other jellyfish. They possess a nerve ring around the base of the bell that coordinates their pulsing movements, a feature found elsewhere only in the crown jellyfish. Whereas some other jellyfish have simple pigment-cup ocelli, box jellyfish are unique in the possession of true eyes, complete with retinas, corneas and lenses. Their eyes are set in clusters called rhopalia, located in pockets halfway up the outer, flat surfaces of the bell. Each contains two rhopalial ocelli with lenses, one directed upwards and the other downwards and inwards towards the manubrium.[7] This enables the animal to see specific points of light, as opposed to simply distinguishing between light and dark. Box jellyfish also have twenty ocelli (simple eyes) that do not form images, but detect light and dark; they therefore have a total of twenty-four eyes.[9] Near the rhopalia are statoliths which detect gravitational pull and help the animal to orient itself.[10]

Box jellyfish also display complex, probably visually-guided behaviors such as obstacle avoidance and fast directional swimming.[11] Research indicates that, owing to the number of rhopalial nerve cells and their overall arrangement, visual processing and integration at least partly happen within the rhopalia of box jellyfish.[11] The complex nervous system supports a relatively advanced sensory system compared to other jellyfish, and box jellyfish have been described as having an active, fish-like behavior.[12]

A fully grown box jellyfish can measure up to 20 cm (7.9 in) along each box side (or 30 cm (12 in) in diameter), and the tentacles can grow up to 3 m (9.8 ft) in length. Its weight can reach 2 kg (4.4 lb).[13] There are about 15 tentacles on each corner. Each tentacle has about 500,000 cnidocytes, containing nematocysts, a harpoon-shaped microscopic mechanism that injects venom into the victim.[14] Many different kinds of nematocysts are found in cubozoans.[15] Click here to READ MORE..!!