South Asian Pigeon

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South Asian pigeon have different beautiful colors.




The Nicobar Pigeon (Caloenas nicobarica) is a pigeon found on small islands and in coastal regions from the Nicobar Islands, east through the Malay Archipelago, to the Solomons and Palau. It is the only living member of the genus Caloenas.

It is a large pigeon, measuring 40 cm in length. The head is grey, like the upper neck plumage, which turns into green and copper hackles towards the breast. The breast and remiges are dark grey. The tail is very short and pure white. The rest of its plumage is metallic green. The cere of the dark bill forms a small blackish knob; the strong legs and feet are dull red. The irides are dark.

Females are slightly smaller than males; they have a smaller bill knob, shorter hackles and browner underparts. Immature birds have a black tail and lack almost all iridescence. There is hardly any variation across the birds' wide range. Even the Palau subspecies C. n. pelewensis has merely shorter neck hackles, but is otherwise almost identical.

It is not a very vocal species, giving a low-pitched repetitive call.

Behaviour and ecology

The Nicobar Pigeon's breeding range encompasses the Andaman and Nicobar Islands of India, the Mergui Archipelago of Myanmar, offshore islands of south-western Thailand, Peninsular Malaysia, southern Cambodia and Vietnam, and many of the small islands between Sumatra, the Philippines and the Solomon Islands. On Palau, the only distinct subspecies C. n. pelewensis is found.

This species nests in dense forest on offshore islets, often in large colonies. It builds a loose stick nest in a tree. It lays one elliptical faintly blue-tinged white eggThe Nicobar Pigeon roams in flocks from island to island, usually sleeping on offshore islets where no predators occur and spends the day in areas with better food availability, not shying away from areas inhabited by humans. Its food consists of seeds, fruit and buds, and it is attracted to areas where grain is available. A gizzard stone helps to grind up hard food items. Its flight is quick, with regular beats and an occasional sharp flick of the wings, as is characteristic of pigeons in general. Unlike other pigeons, groups tend to fly in columns or single file, not in a loose flock. The white tail is prominent in flight when seen from behind and may serve as a sort of "taillight", keeping flocks together when crossing the sea at dawn or dusk. The young birds' lack of a white tail is a signal of their immaturity clearly visible to conspecifics – to an adult Nicobar Pigeon, it is obvious at a glance which flock members are neither potential mates, nor potential competitors for mates, nor old enough to safely guide a flock from one island to another.

Habitat

On the Nicobar Islands (which are referred to in its common and scientific names), the most significant colony in our time was found on Batti Malv, a remote wildlife sanctuary between Car Nicobar and Teressa. The 2004 Indian Ocean tsunami caused massive damage on the Nicobar Islands, and it is still not quite clear to what extent Batti Malv was affected. But while everything on some islets in the Great Nicobar Biosphere Reserve was destroyed, Batti Malv lighthouse – a skeletal tower a dozen metres high, standing a few metres ASL at the highest point of the low-lying island – was little-damaged and put back in operation by the survey ship INS Sandhayak less than one month after the disaster. An April 2007 survey by the Indian Coast Guard vessel ICGS Vikram found the lighthouse tower "totally covered" in vines, indicating rampant regeneration of vegetation – but perhaps also that damage to the island's forest was severe, as a cover of creeping plants is typical of early succession stages, while a photo of the lighthouse taken before the tsunami shows rather mature 

ZEBRA

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Zebra - with black and white stripes is called a African donkey.

Zebras  are several species of African equids (horse family) united by their distinctive black and white stripes. Their stripes come in different patterns, unique to each individual. They are generally social animals that live in small harems to large herds. Unlike their closest relatives, horses and asses, zebras have never been truly domesticated.

There are three species of zebras: the plains zebra, the Grévy's zebra and the mountain zebra. The plains zebra and the mountain zebra belong to the subgenus Hippotigris, but Grévy's zebra is the sole species of subgenus Dolichohippus. The latter resembles an ass, to which it is closely related, while the former two are more horse-like. All three belong to the genus Equus, along with other living equids.

The unique stripes of zebras make them one of the animals most familiar to people. They occur in a variety of habitats, such as grasslands, savannas,woodlands, thorny scrublands, mountains, and coastal hills. However, various anthropogenic factors have had a severe impact on zebra populations, in particular hunting for skins and habitat destruction. Grévy's zebra and the mountain zebra are endangered. While plains zebras are much more plentiful, one subspecies, the quagga, became extinct in the late 19th century – though there is currently a plan, called the Quagga Project, that aims to breed zebras that are phenotypically similar to the quagga in a process called breeding back.

Etymology

Zebra in English dates back to c.1600, from Italian Zebra, perhaps from Portuguese, which in turn is said to be Congolese (as stated in the Oxford English Dictionary). The Encarta Dictionarysays its ultimate origin is uncertain, but perhaps it may come from Latin Equiferus meaning "Wild horse," from equus "horse" and ferus "wild, untamed".

Taxonomy and evolution

Horse evolution Zebras evolved among the Old World horses within the last 4 million years. Grévy's zebras (and perhaps also Mountain Zebras) are, together with asses and donkeys, in a separate lineage from other zebra lineages.This means either that striped equids evolved more than once, or that common ancestors of zebras and asses were striped and only zebras retained the stripes. Extensive stripes are posited to have been of little use to equids that live in low densities in deserts (like asses and some horses) or ones that live in colder climates with shaggy coats and annual shading (like some horses).

Fossils of an ancient equid were discovered in the Hagerman Fossil Beds National Monument in Hagerman, Idaho. It was named the Hagerman horsewith a scientific name of Equus simplicidens. It is believed to have been similar to the Grévy's zebra. The animals had stocky zebra-like bodies and short, narrow, donkey-like skulls. Grévy's zebra also has a donkeylike skull. The Hagerman horse is also called the American zebra or Hagerman zebra.

Size and weight

The common plains zebra is about 50–52 inches (12.2–13 hands, 1.3 m) at the shoulder with a body ranging from 6–8.5 feet (2–2.6 m) long with an 18-inch (0.5 m) tail. It can weigh up to 770 pounds (350 kg), males being slightly bigger than females. Grévy's Zebra is considerably larger, while the mountain zebra is somewhat smaller.

Gaits

Like horses, zebras walk, trot, canter and gallop. They are generally slower than horses, but their great stamina helps them outpace predators. When chased, a zebra will zig-zag from side to side, making it more difficult for the predator. When cornered, the zebra will rear up and kick or bite its attacker.

SEA HORSE

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A small fish having a head like that of a horse is known as - Sea horse.



Seahorse is the title given to 54 species of marine fish in the genus Hippocampus. "Hippocampus" comes from the Ancient Greek hippos meaning "horse" and kampos meaning "sea monster".

Habitat

Seahorses are mainly found in shallow tropical and temperate waters throughout the world, and prefer to live in sheltered areas such as seagrass beds,estuaries, coral reefs, or mangroves. In Pacific waters from North America to South America there are four species. In the Atlantic, the H. erectusranges from Nova Scotia to Uruguay. H. zosterae, known as the dwarf seahorse, is found in the Bahamas.

Colonies have been found in European waters such as the Thames Estuary.

Three species live in the Mediterranean Sea: H. guttulatus (the long-snouted seahorse), H. hippocampus (the short-snouted seahorse) and H. fuscus(the sea pony). These species form territories; males stay within 1 square meter (11 sq ft) of their habitat while females range about one hundred times that.

Physical description

Seahorses swim very poorly, rapidly fluttering a dorsal fin and using pectoral fins (located behind their eyes) to steer. The slowest-moving fish in the world is H. zosterae (the dwarf seahorse), with a top speed of about 5 feet (150 cm) per hour. Seahorses have no caudal fin. Since they are poor swimmers, they are most likely to be found resting with their prehensile tails wound around a stationary object. They have long snouts, which they use to suck up food, and eyes that can move independently of each other (like those of a chameleon).Seahorses range in size from 0.6 to 14 in (1.5 to 35.5 cm). They are named for their equine appearance. Although they are bony fish, they do not have scales but rather thin skin stretched over a series of bony plates, which are arranged in rings throughout their body. Each species has a distinct number of rings. Seahorses swim upright, another characteristic that is not shared by their close pipefish relatives, who swim horizontally. Razorfish are the only other fish that swim vertically like a seahorse. Unusual among fish, seahorses have a flexible, well-defined neck. They also sport a coronet on the head, which is distinct for each individual.

Evolution and fossil record

Anatomical evidence, supported by molecular, physical, and genetic evidence, demonstrates that seahorses are highly modified pipefish. The fossil record of seahorses, however, is very sparse. The best known and best studied fossils are specimens of H. guttulatus (though literature more commonly refers to them under the synonym of H. ramulosus), from the Marecchia River Formation of Rimini Province, Italy, dating back to the Lower Pliocene, about 3 million years ago. The earliest known seahorse fossils are of two pipefish-like species, H. sarmaticus and H. slovenicus from the coprolitic horizon of Tunjice Hills, a middle Miocene lagerstätte in Slovenia dating back about 13 million years. Molecular dating finds that pipefish and seahorses separated during the Late Oligocene. This has led to speculation that seahorses evolved in response to large areas of shallow-water, newly created as the result of tectonic events. The shallow water allowed the expansion of seagrass habitats that selected for the camouflage offered by the seahorses’ upright posture. These tectonic changes occurred in the Western Pacific Ocean suggesting an origin there with molecular data suggesting two later and separate invasions of the Atlantic Ocean.

VERTEBRATES

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Animals having backbone (vertebra) are known as - Vertebrates.

Vertebrates  are animals that are members of the subphylum Vertebrata (chordates with backbones). Vertebrates include the overwhelming majority of the phylum Chordata, with currently about 64,000 species described. Vertebrates include the amphibians, reptiles,mammals, and birds, as well as the jawless fish, bony fish, sharks and rays. Extant vertebrates range in size from the frog species Paedophryne amauensis, at as little as 7.7 mm (0.3 inch), to the blue whale, at up to 33 m (110 ft). Vertebrates make up about 4% of all described animal species; the rest are invertebrates, which lack backbones.

The vertebrates traditionally include the hagfish, which do not have proper vertebrae, though their closest living relatives, the lampreys, do have vertebrae. Hagfish do, however, possess a cranium. For this reason, the vertebrate subphylum is sometimes referred to as "Craniata" when discussing morphology. Molecular analysis since 1992 has suggested that the hagfish are most closely related to lampreys, and so also are vertebrates in amonophyletic sense. Others consider them a sister group of vertebrates in the common taxon of Craniata.

OCTOPUS

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How many arms an octopus has - Eight everyone know it but do u know The arms of the octopus are called - Tentacles.

The octopus is a cephalopod mollusc of the order Octopoda. Octopuses have two eyes and four pairs of arms and, like other cephalopods, they are bilaterally symmetric. An octopus has a hard beak, with its mouth at the center point of the arms. Octopuses have no internal or external skeleton (although some species have a vestigial remnant of a shell inside their mantles), allowing them to squeeze through tight places. Octopuses are among the most intelligent and behaviorally flexible of all invertebrates.

The octopus inhabits many diverse regions of the ocean, including coral reefs, pelagic waters, and the ocean floor. They have numerous strategies for defending themselves against predators, including the expulsion of ink, the use of camouflage and deimatic displays, their ability to jet quickly through the water, and their ability to hide. An octopus trails its eight arms behind it as it swims. All octopuses are venomous, but only one group, the blue-ringed octopus, is known to be deadly to humans.

Around 300 species are recognized, which is over one-third of the total number of known cephalopod species. The term 'octopus' may also be used to refer only to those creatures in the genus Octopus.

HUMMING BIRD

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The smallest bird alive is the - Humming bird.




Hummingbirds are birds that comprise the family Trochilidae. They are among the smallest of birds, most species measuring in the 7.5–13 cm (3–5 in) range. Indeed, the smallest extant bird species is a hummingbird, the 5-cm Bee Hummingbird. They hover in mid-air by rapidly flapping their wings12–80 times per second (depending on the species). They are known as hummingbirds because of the humming sound created by their beating wings, which sometimes sounds like bees or other insects. To conserve energy while they sleep or when food is scarce, they have the ability to go into a hibernation-like state (torpor) where their metabolic rate is slowed to 1/15th of its normal rate. When the nights get colder, their body temperature can drop significantly and thus slow down their heart and breathing rate, thus burning much less energy overnight. As the day heats back up, the hummingbirds' body temperature will come back up and they resume their normal activity. They can fly at speeds exceeding 15 m/s (54 km/h; 34 mph);they are also the only group of birds with the ability to fly backwards. Individuals from some species of hummingbirds weigh less than apenny.

Diet and specialization for food gathering

Most hummingbird species have bills that are long and straight or nearly so, but in some species the bill shape is adapted for specialized feeding. Thornbills have short, sharp bills adapted for feeding from flowers with short corollas and piercing the bases of longer ones. The Sicklebills' extremely decurved bills are adapted to extracting nectar from the curved corollas of flowers in the family Gesneriaceae. The bill of the Fiery-tailed Awlbill has an upturned tip, as in the Avocets. The male Tooth-billed Hummingbird has barracuda-like spikes at the tip of its long, straight bill.Hummingbirds drink nectar, a sweet liquid inside certain flowers. Like bees, they are able to assess the amount of sugar in the nectar they eat; they reject flower types that produce nectar that is less than 10% sugar and prefer those whose sugar content is higher. Nectar is a poor source of nutrients, so hummingbirds meet their needs for protein, amino acids, vitamins, minerals, etc. by preying on insects and spiders.

The two halves of a hummingbird's bill have a pronounced overlap, with the lower half (mandible) fitting tightly inside the upper half (maxilla). When hummingbirds feed on nectar, the bill is usually opened only slightly, allowing the tongue to dart out and into the interior of flowers.

While it had been believed that hummingbirds drink via capillary action, high-speed photography has revealed that a hummingbird's tongue’s tubes open down their sides, and close around nectar. Hummingbirds do not spend all day flying, as the energy cost would be prohibitive; the majority of their activity consists simply of sitting or perching. Hummingbirds eat many small meals and consume as much as twelve times their body weight in nectar each day. Hummingbirds digest their food rapidly due to their small size and high metabolism; a mean retention time (MRT) of less than an hour has been reported. Hummingbirds spend an average of 10–15% of their time feeding and 75–80% sitting and digesting.

Hummingbirds are typically very territorial when it comes to food; once a hummingbird finds a consistent source of food such as an artificial feeder, it will fight off other hummingbirds to maintain complete dominance over the food source.

OSTRICH

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The largest bird alive is the - Ostrich, Everyone know it but do u know It is widely believed that Ostrich buries its head in sand which is Not true.

The Ostrich or Common Ostrich (Struthio camelus) is either one or two species of large flightless birds native to Africa, the only living member(s) of the genus Struthio, which is in the ratite family. Some analyses indicate that the Somali Ostrich may be better considered a full species separate from the Common Ostrich, but most taxonomists consider it to be a subspecies.

The ostrich shares the order Struthioniformes with the kiwis, emus, rheas, and cassowaries. It is distinctive in its appearance, with a long neck and legs, and can run at up to about 70 km/h (43 mph), the fastest land speed of any bird. The ostrich is the largest living species of bird and lays the largest eggs of any living bird (extinct elephant birds of Madagascar and the giant moa of New Zealand laid larger eggs).

The ostrich's diet consists mainly of plant matter, though it also eats invertebrates. It lives in nomadic groups of 5 to 50 birds. When threatened, the ostrich will either hide itself by lying flat against the ground, or run away. If cornered, it can attack with a kick of its powerful legs. Mating patterns differ by geographical region, but territorial males fight for a harem of two to seven females.

The ostrich is farmed around the world, particularly for its feathers, which are decorative and are also used as feather dusters. Its skin is used forleather products and its meat is marketed commercially.

Description

Ostriches usually weigh from 63 to 145 kilograms (139–320 lb), Ostriches of the East African race (S. c. massaicus) averaged 115 kg (254 lb) in males and 100 kg (220 lb) in females, while the nominate subspecies^{[clarification needed]} was found to average 111 kg (245 lb) in unsexed adults. Exceptional male ostriches (in the nominate subspecies) can weigh up to 156.8 kg (346 lb). At sexual maturity (two to four years), male ostriches can be from 2.1 to 2.8 m (6 ft 11 in to 9 ft 2 in) in height, while female ostriches range from 1.7 to 2 m (5 ft 7 in to 6 ft 7 in) tall. New chicks are fawn in colour, with dark brown spots. During the first year of life, chicks grow at about 25 cm (9.8 in) per month. At one year of age, ostriches weigh approximately 45 kilograms (99 lb). Their lifespan is up to 40–45 years.

The feathers of adult males are mostly black, with white primaries and a white tail. However, the tail of one subspecies is buff. Females and young males are greyish-brown and white. The head and neck of both male and female ostriches is nearly bare, with a thin layer of down. The skin of the female's neck and thighs is pinkish gray, while the male's is blue-gray, gray or pink dependent on subspecies.

ALBATROSS

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Albatross is a large - Sea bird.

Albatrosses, of the biological family Diomedeidae, are large seabirds allied to the procellariids, storm-petrels and diving-petrels in the order Procellariiformes (the tubenoses). They range widely in the Southern Ocean and the North Pacific. They are absent from the NorthAtlantic, although fossil remains show they once occurred there too and occasional vagrants are found. Albatrosses are among the largest of flying birds, and the great albatrosses (genus Diomedea) have the largest wingspans of any extant birds, reaching up to 12 feet (3.7 m). The albatrosses are usually regarded as falling into four genera, but there is disagreement over the number of species.

Albatrosses are highly efficient in the air, using dynamic soaring and slope soaring to cover great distances with little exertion. They feed on squid, fish and krill by either scavenging, surface seizing or diving. Albatrosses are colonial, nesting for the most part on remote oceanic islands, often with several species nesting together. Pair bonds between males and females form over several years, with the use of 'ritualised dances', and will last for the life of the pair. A breeding season can take over a year from laying to fledging, with a single egglaid in each breeding attempt. A Laysan albatross, named "Wisdom" on Midway Island is recognized as the oldest wild bird in the world; she was first banded in 1956 by Chandler Robbins.

Diet

The use of data loggers at sea that record ingestion of water against time (providing a likely time of feeding) suggest that albatross predominantly feed during the day. Analysis of the squid beaks regurgitated by albatrosses has shown that many of the squid eaten are too large to have been caught alive, and include mid-water species likely to be beyond the reach of albatross, suggesting that, for some species (like the Wandering Albatross), scavenged squid may be an important part of the diet. The source of these dead squid is a matter of debate; some certainly comes from squid fisheries, but in nature it primarily comes from the die-off that occurs after squid spawning and the vomit of squid-eating whales (sperm whales, pilot whales and Southern Bottlenose Whales). The diet of other species, like the Black-browed Albatross or the Grey-headed Albatross, is rich with smaller species of squid that tend to sink after death, and scavenging is not assumed to play a large role in their diet. Also the Waved Albatross has been observed practicing kleptoparasitism, harassing boobies to steal their food, making it the only member of its order to do so regularly. The albatross diet is predominantly cephalopods, fish, crustaceans, and offal, although they will also scavenge carrion and feed on other zooplankton. It should be noted that for most species, a comprehensive understanding of diet is only known for the breeding season, when the albatrosses regularly return to land and study is possible. The importance of each of these food sources varies from species to species, and even from population to population; some concentrate on squid alone, others take more krill or fish. Of the two albatross species found in Hawaii, one, the Black-footed Albatross, takes mostly fish while the Laysan feeds on squid.

Until recently it was thought that albatross were predominantly surface feeders, swimming at the surface and snapping up squid and fish pushed to the surface by currents, predators, or death. The deployment of capillary depth recorders, which record the maximum dive depth undertaken by a bird (between attaching it to a bird and recovering it when it returns to land), has shown that while some species, like the Wandering Albatross, do not dive deeper than a metre, some species, like the Light-mantled Albatross, have a mean diving depth of almost 5 m and can dive as deep as 12.5 m. In addition to surface feeding and diving, they have now also been observed plunge diving from the air to snatch prey.

HIBERNATION

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A period of dormancy in winter by some animals known as - Hibernation.

Hibernation is a suppressed metabolic state that falls under the umbrella-term of torpor or dormancy, which covers all forms of metabolic suppression. Hibernation, like other forms of torpor, is a widespread and common survival strategy expressed under the threat of a metabolic energy crisis. As the name suggests, however, it has a seasonal connotation suggestive of triggering by lowered ambient temperatures and darkness, e.g., autumn and winter.

Attempts at defining hibernation have proved elusive. For example, merely exposing animals that hibernate does not always trigger hibernation. Instead it may trigger a hypothermia, which is a life-threatening pathologic condition. In addition, the duration for which an animal must remain in torpor to be qualified as a hibernator remains debatable. Depe

nding on the species, it's size, environmental trigger (e.g., ambient temperature, light levels, etc.), time of year, body condition, and fat stores, hibernation could arguably last as short as a day or less, or many months. Indeed, for some animals that spend the greater part of the year in hibernation, it is the default-mode of existence. The longest reported hibernation bout on record in a mammal, a marsupial, is just over a year (ref). Additional difficulty in defining hibernation comes by way of the fact that small mammals frequently arouse during hibernation. Unequivocally, however, torpid states, whatever the metabolic energy threat, are fundamentally typified by lowered core-body temperatures, prolonged pauses between breaths and lowered heart rates, i.e., to values below those of BMR. Even here though, it remains unclear what degree of suppression is required. The fact that the scope for metabolic rate reduction scales with body mass, means that large animals, because of an already lowered size-related basal metabolic rate require less scope for reaching the universal minimum metabolic rate (UMMR), a rate found to be invariant in animals varying in size from bacteria to blue whales. In other words, only a ca. 75% decrease in metabolic rate below BMR is required to reach the UMMR in animals the size of, say, bears or even a seal, compared to say a small rodent, the latter of which can lower metabolic rate to single digit percentages of BMR. This is also why small animals are able to cool, track and tolerate ambient temperature better than larger animals, and also why bears were not considered true hibernators by many for such a long time. It is becoming evident, however, that the torpor can be triggered by many metabolic energy threats and comes in many shades, form a continuum that utilize similar underlying mechanisms.Hibernation during the summer months is known as aestivation. Some reptile species (ectotherms) are said to brumate, or undergo brumation, but any possible similarities between brumation and hibernation are not firmly established.

PRIDE - GROUP OF LION

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A group of lions is called a - Pride.


The name comes from the old English  'pryto', which comes from 'prud' . First applied to groups of lions in 1486, but not commonly so used until c.1930. The verb in the reflexive sense "congratulate oneself" is recorded from 1275.

Pride of Lions is a melodic rock group fronted by former Survivor guitarist/keyboardist Jim Peterik and vocalist Toby Hitchcock. Formed in 2003, the group, according to Peterik is "my vision of the best elements of the great melodic rock era of the 80’s, updated of course with more modern production sounds."

VETERINARIAN

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An animal doctor is called - a Veterinarian.

A veterinary physician, colloquially called a vet, shortened from veterinarian (American English, Australian English) or veterinary surgeon (British English), is a professional who practices veterinary medicine by treating disease, disorder, and injury in non-human animals.

In many countries, the local nomenclature for a vet is a regulated and protected term, meaning that members of the public without the prerequisite qualifications and/or registration are not able to use the title. In many cases, the activities that may be undertaken by a veterinarian (such as animal treatment or surgery) are restricted only to those professionals who are registered as vet. For instance, in the United Kingdom, as in other jurisdictions, animal treatment may only be performed by registered vets (with a few designated exceptions, such as paraveterinary workers), and it is illegal for any person who is not registered to call themselves a vet or perform any treatment.

Most vets work in clinical settings, treating animals directly. These vets may be involved in a general practice, treating animals of all types; may be specialized in a specific group of animals such as companion animals, livestock, zoo animals or horses; or may specialize in a narrow medical discipline such as surgery, dermatology or internal medicine.

As with healthcare professionals, vets face ethical decisions about the care of their patients. Current debates within the profession include the ethics of purely cosmetic procedures on animals, such as declawing of cats, docking of tails, cropping of ears and debarking on dogs.

ARTHROPODS

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A group of invertebrate animals which have segments body and jointed limbs are called - Arthropods.

An arthropod is an invertebrate animal having an exoskeleton (external skeleton), a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda (from Greek ἄρθρον árthron, "joint", and πούς pous (gen. podos), i.e. "foot" or "leg", which together mean "jointed leg"), and include the insects, arachnids, and crustaceans. Arthropods are characterized by their jointed limbs and cuticles, which are mainly made of α-chitin; the cuticles of crustaceans are also biomineralized with calcium carbonate. The rigid cuticle inhibits growth, so arthropods replace it periodically by moulting. The arthropod body plan consists of repeated segments, each with a pair of appendages. Their versatility has enabled them to become the most species-rich members of all ecological guilds in most environments. They have over a million described species, making up more than 80% of all described living animal species, some of which, unlike most animals, are very successful in dry environments. They range in size from microscopic plankton up to forms a few meters long.

Description

Arthropods are invertebrates with segmented bodies and jointed limbs. The limbs form part of an exoskeleton, which is mainly made of α-chitin, a derivative of glucose. One other group of animals, the tetrapods, has jointed limbs, but tetrapods are vertebrates and therefore have endoskeletons. Arthropods bony back evolved so that it became segmented letting it move about more freely and not reducing its protection.

Diversity

One estimate indicates that arthropods have 1,170,000 described species, and account for over 80% of all known living animal species. Another study estimates that there are between 5 to 10 million extant arthropod species, both described and yet to be described. Estimating the total number of living species is extremely difficult because it often depends on a series of assumptions in order to scale up from counts at specific locations to estimates for the whole world. A study in 1992 estimated that there were 500,000 species of animals and plants in Costa Rica alone, of which 365,000 were arthropods. Arthropods are one of the most ubiquitous groups of multicellular organisms found in the biosphere.

They are important members of marine, freshwater, land and air ecosystems, and are one of only two major animal groups that have adapted to life in dry environments; the other is amniotes, whose living members are reptiles, birds and mammals. One arthropod sub-group, insects, is the most species-rich member of all ecological guilds in land and fresh-water environments. The lightest insects weigh less than 25 micrograms (millionths of a gram), while the heaviest weigh over 70 grams (2.5 oz). Some living crustaceans are much larger; for example, the legs of the Japanese spider crab may span up to 4 metres (13 ft).

BLACK MAMBA

DO U KNOW IT?


The fastest moving land snake in the world is the - Black Mamba.

The black mamba (Dendroaspis polylepis), also called the common black mamba or black-mouthed mamba, is the longest venomous snake in Africa, averaging around 2.5 to 3.2 m (8.2 to 10 ft) in length, and sometimes growing to lengths of 4.45 m (14.6 ft). It is named for the black colour of the inside of the mouth rather than the colour of its scales which varies from dull yellowish-green to a gun-metal grey. It is also the fastest snake in the world, capable of moving at 4.32 to 5.4 metres per second (16–20 km/h, 10–12 mph). The black mamba has a reputation for being very aggressive, but it usually attempts to flee from humans like most snakes, unless it is threatened.Without rapid and vigorous antivenom therapy, a bite from a black mamba is almost always fatal.

Taxonomy

The black mamba was first described in 1864 by Albert Günther, a German-born British zoologist, ichthyologist, and herpetologist. Soon after, a subspecies was identified, Dendroaspis polylepis antinorii (Peters, 1873), but this is no longer accepted as distinct. The genus and species name are derived from Ancient Greek words – Dendroaspis meaning "tree asp" (dendro is "tree", while aspis is "asp" which is understood to mean a "venomous snake") and polylepis, "many scaled", from poly "many" and lepis "scales". The name "black mamba" is given to the snake not because of its body colour but because of the ink-black colouration of the inside of its mouth, which it displays when threatened. In 1896, Boulengercombined the species (Dendroaspis polylepis) as a whole with the eastern green mamba, Dendroaspis angusticeps, and they were considered a single species from 1896 until 1946.

It is one of four species in the African snake genus Dendroaspis that are known as mambas.

Description

The adult black mamba's back skin colour is olive, brownish, gray, or sometimes khaki. A young snake is lighter, but not light enough to be confused with the different species of green mamba. Its underbody is cream-coloured, sometimes blended with green or yellow. Dark spots or blotches may speckle the back half of the body, and some individuals have alternating dark and light scales near the posterior, giving the impression of lateral bars. The inside of the mouth is dark blue to inky black. The head is large but narrow and elongated, with the shape of a coffin. It is a proteroglyphous snake, meaning it has immovable, fixed fangs at the front of the maxilla. The eyes are dark brown to black, with a silvery-white to yellow edge on the pupils. These snakes are strong but slender in body: adult specimens are 2.5 to 3 m (8.2 to 9.8 ft) in length on average, but specimens measuring 3.1 to 3.75 m (10 to 12.3 ft) are relatively common, and some specimens have reached lengths of 4.3 to 4.5 m (14 to 15 ft). The longest scientifically measured, wild-caught black mamba recorded was 4.48 metres (14.7 ft) long, found in Zimbabwe. Adult black mambas' slender but powerful body can typically weigh from 1.6 to 3.1 kg (3.5 to 6.8 lb). There is no real sexual dimorphism, and both male and female snakes of this species have a similar appearance and tend to be similar in size. The species is the second-longest venomous snake in the world, exceeded in length only by the king cobra. Information regarding the lifespan of snakes in the wild is sparse; the longest recorded lifespan of a captive black mamba is 14 years, but actual maximum lifespans could be much greater. As they age, their colouration tends to get darker.

Scalation

There are 23–25 rows of smooth dorsal scales at midbody (rarely 21 rows), 248–281 ventrals and 109–132 paired subcaudals. The anal shield is divided. There are 7–10 upper labials, with the fourth (or third and fourth) entering the eye, and 11–13 lower labials (sometimes 10 or 14). There are three (sometimes four) preoculars and three or four (sometimes two or five) postoculars. Temporals are variable, usually 2+3.