Deadliest Animals

They are Responsible

For simplicity's sake, we're going to assume you wish to know what animal is responsible for the most human deaths per year. Thankfully, the good people at the Smithsonian National Zoological Park have the answer.

Poison Dart Frog

Poison dart frog (also poison arrow frog, dart frog or poison frog) is the common name of the Dendrobatidae family of small, diurnal frogs. Poison dart frogs are native to Central and South America. The frogs are widely called poison arrow frogs or poison dart frogs, a generalization reflecting the widespread notion that all poison frogs are used by South American tribes in the manufacture of poison that is spread on arrows or blow-gun darts. In actuality, of over 175 species of poison frog, only three are toxic enough to use for this purpose, and none come from the Dendrobates genus, which is most characterized by the brilliant color and complex patterns of its member species.

Scientists have discovered that poison dart frogs cannot actually manufacture any of the toxic alkaloids they defend themselves with. Though they did not evolve the ability to produce the toxins, they did evolve a predatory relationship with alkaloid-rich ants and other invertibrates from which they extract potent alkaloids such as pumiliotoxins, one of many varieties of batrachotoxins. In captivity, the frogs are fed cultured insects that do not represent their diet in the wild. Since easily purchasable foods such as fruit flies and extra-small crickets are not rich in the required alkaloids, in captivity poison frogs do not produce toxins, and those captured from the wild gradually lose their toxicity. In fact, many hobbyists and herpetologists have reported that most dart frogs will not consume ants at all in captivity, though ants comprise the larger portion of their diet in the wild. Though all poison frogs lose their toxicity when deprived of certain foods, and captive-bred poison dart frogs are born harmless, a wild-caught poison dart frog can retain alkaloids for years.

Scientists have recently found that some poison frogs not only absorb the alkaloids of ants, but even have the ability to modify them, creating more toxic variants. For example, while Dendrobates auratus consumes pumiliotoxin 251D and merely stores it, some members of the Dendrobatidae family convert pumiliotoxin 251D to allopumiliotoxin 267A, which is five times more toxic than the original version. The most toxic poison frog of all is the Golden Poison Frog (Phyllobates terribilis). It is estimated that one frog harbors enough toxin at any given time to kill between 10 and 20 adult humans. Because they are vile-tasting and usually deadly when ingested, poison frogs have no natural predators, and this is one factor that adds to their popularity as pets: Since they have no natural predators, the frogs are not bothered at all by the close presence of large animals, including humans.

Poison frogs are creatures of great scientific interest to evolutionary biologists. The frog's intriguing ability to resist, store, and manipulate toxins, along with its related role in the food chain, are among the most important discoveries in the study of food chain evolution. Biologists have speculated that the frogs must have first evolved a resistance to the alkaloids in response to using the ants as a food source. The ability to digest even toxic foods allowed them to capitalize on an otherwise untouched food source, a fairly common event on the evolutionary scale. Once having developed a resistance to such foods over the course of countless generations, any genetic variation that happened to make the ingested poison accumulate closer to the skin's surface would have bestowed a greater advantage with each beneficial mutation. Secreting this new weapon, they would have then evolved their bright colors and adapted to a diurnal schedule in response to the absence of natural predators, and some frogs would go as far as to evolve the ability to manipulate the toxins they consumed, thus increasing their deterrence to predators and their likelihood to survive.

Cape Buffalo

The African Buffalo or Cape Buffalo (Syncerus caffer) is a bovid from the family of the Bovidae. It is up to 1.7 meters high, 2.8 meters long. On average, an adult male stands about 1.5 m high at the shoulder and weighs 600–750 kg, while a female is 10–15 cm shorter and weighs between 400 and 550 kg. Bulls at ten years of age or older can reach or exceed 900 kg. The African Buffalo is not closely related to the slightly larger Wild Asian Water Buffalo, but its ancestry remains unclear. Owing to its unpredictable nature which makes it highly dangerous to humans, it has not been domesticated like its Asian counterpart, the Domestic Asian Water Buffalo.

The Cape Buffalo is a very powerful creature, demanding respect from even a pride of lions when paths cross. Other than humans, they have few natural predators and are capable of defending themselves against (and sometimes killing) lions. Lions do kill and eat buffalo regularly, but it typically takes multiple lions to bring down a single adult buffalo; only large male lions have been known to take down adult buffalo on their own. The leopard and spotted hyena are a threat only to newborn calves. The African Buffalo has never been domesticated.

Known as one of the "big five" in Africa, the African Buffalo is widely regarded as a very dangerous animal, as it gores and kills several people every year. Buffalo are sometimes reported to kill more people in Africa than any other animal, although the same claim is sometimes made of Hippopotami or Crocodiles. Buffalo are notorious among big game hunters as very dangerous animals, with wounded animals reported to ambush and attack pursuers.

Cape Buffalo occur from open savannah to thickly wooded country, and wallow when the opportunity presents itself. They are found in Sudan, Ethiopia, Somalia, Zambia, Zimbabwe, Namibia, Botswana, Mozambique, South Africa, Kenya and Tanzania.

The main herd consists of females and their offspring. Males will form bachelor groups with dominance hierarchies. Old males normally live alone. A male is recognizable by the thickness of his horns, and is called the "Boss." During the mating season the bachelor groups stay with the herd and fight among each other for females.

Cows first calve at five years of age, after a gestation period of 11.5 months. Newly born calves remain hidden in vegetation for the first few weeks while being nursed occasionally by the mother before joining the main herd. Calves are held in the centre of the herd for safety. Males leave their mothers when they are two years old and join the bachelor groups.

The current status of African cape buffalo is dependant on the existence of the animals value to both trophy hunters and tourist paying the wave for conservation efforts through anti-poaching patrols, village crop damage payouts, and CAMPFIRE payback programs to local areas.

The current total number of cape buffalo is spread throughout non-desert southern Africa from the Egypt in the North to South Africa in the South. The cape buffalo are estimated to number around a million, but quality counts are not possible with the lack of research funding in places like Sudan, Chad, Zaire, and Benin. Most professional hunters, safari outfitters, and wildlife professionals believe the number to be only representing the actual Cape subspecies, and not counting the Nile, North-East, or Forest buffalo.

Polar Bear

The polar bear (Ursus maritimus) is a bear native to the Arctic. Polar bears and Kodiak bears are the world's largest land carnivores, with most adult males weighing 300-600 kg (660-1320 lb); adult females are about half the size of males. Its fur is hollow and translucent, but usually appears as white or cream colored, thus providing the animal with effective camouflage. Its skin is actually black in color. Its thick blubber and fur insulate it against the cold. The bear has a short tail and small ears that help reduce heat loss, as well as a relatively small head and long, tapered body to streamline it for swimming.

A semi-aquatic marine mammal, the polar bear has adapted for life on a combination of land, sea, and ice, and is the apex predator within its range. It feeds mainly on seals, young walruses, and whales, although it will eat anything it can kill. It is the bear species most likely to prey on humans.

The polar bear is a vulnerable species at high risk of extinction. Zoologists and climatologists believe that the projected decreases in the polar sea ice due to global warming will reduce their population by two thirds by mid-century. Local long-term studies show that 7 out of 19 subpopulations are declining or already severely reduced. In the USA, the Center for Biological Diversity petitioned to up-list the legal conservation status of polar bears to threatened species in 2005. This petition is still under review.

Size and weight

Polar bears rank with the Kodiak bear as among the largest living land carnivores, and male polar bears may weigh twice as much as a Siberian tiger. Most adult males weigh 350–650 kg (770–1500+ lb) and measure 2.5–3.0 m (8.2–9.8 ft) in length. Adult females are roughly half the size of males and normally weigh 150–250 kg (330–550 lb), measuring 2–2.5 m (6.6–8.2 ft), but double their weight during pregnancy. The great difference in body size makes the polar bear among the most sexually dimorphic of mammals, surpassed only by the eared seals. At birth, cubs weigh only 600–700 g or about a pound and a half. The largest polar bear on record was a huge male, allegedly weighing 1002 kg (2200 lb) shot at Kotzebue Sound in northwestern Alaska in 1960.

A polar bear's fur provides camouflage and insulation. Although the fur appears white, in fact the individual hairs are translucent, like the water droplets that make up a cloud; the coat may yellow with age. Stiff hairs on the pads of a bear's paws provide insulation and traction on the ice.

Polar bears gradually molt their hair from May to August; however, unlike other Arctic mammals, polar bears do not shed their coat for a darker shade to camouflage themselves in the summer habitat. It was once conjectured that the hollow guard hairs of a polar bear coat acted as fiber-optic tubes to conduct light to its black skin, where it could be absorbed - a theory disproved by recent studies.

The thick undercoat does, however, insulate the bears: they overheat at temperatures above 10 °C (50 °F), and are nearly invisible under infrared photography; only their breath and muzzles can be easily seen. When kept in captivity in warm, humid conditions, it is not unknown for the fur to turn a pale shade of green. This is due to algae growing inside the guard hairs — in unusually warm conditions, the hollow tubes provide an excellent home for algae. Whilst the algae is harmless to the bears, it is often a worry to the zoos housing them, and affected animals are sometimes washed in a salt solution, or mild peroxide bleach to make the fur white again.

The guard hair is 5-15 cm over most of the body of polar bears. However, in the forelegs, males have significantly longer, increasing in length until 14 years of age. The ornamental foreleg hair is suggested as a form of an attractive trait for females, likened to the lion mane.

Elephant

The elephants (Elephantidae) are a family in the order Proboscidea in the class Mammalia. They were once classified along with other thick skinned animals in a now invalid order, Pachydermata. There are three living species: the African Bush Elephant, the African Forest Elephant (until recently known collectively as the African Elephant), and the Asian Elephant (also known as the Indian Elephant). Other species have become extinct since the last ice age, which ended about 10,000 years ago, the Mammoth being the most well-known of these.

The word "elephant" has its origins in the Greek ??????, meaning "ivory" or "elephant".

Elephants are mammals, and the largest land animals alive today. 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 (265 lb). An elephant may live as long as 70 years, sometimes longer. The largest elephant ever recorded was shot in Angola in 1956. This male weighed about 12,000 kg (26,400 lb), with a shoulder height of 4.2 m (13.8 ft), a metre (3 ft 4 in) 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.

Elephants are symbols of wisdom in Asian cultures, and are famed for their memory and high intelligence, and 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."

Elephants are 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. Elephants generally have no natural predators, although lions may take calves and occasionally adults. In some areas, lions may regularly take to preying on elephants.

Australian Saltwater Crocodile

The Saltwater or Estuarine Crocodile (Crocodylus porosus) is the largest of all living crocodilians and reptiles. It is found in suitable habitat throughout Southeast Asia and northern Australia. Saltwater crocodiles are known in the Northern Territory of Australia as 'salties'. The Alligator Rivers are misnamed after the resemblance of the 'saltie' to alligators as compared to freshwater crocodiles, which also inhabit the Northern Territory.

An average adult male saltwater crocodile is typically 5 metres (17 feet) long, and weighs around 1000 pounds. However the maximum size of the saltwater crocodile is well over 7m (23ft) in length and over 2200 pounds (1000 kg). The largest living saltwater crocodile is a 7.1m (23.3ft) crocodile in Orissa, India. The largest confirmed estuarine crocodile is a 8.6m (28.3ft) crocodile shot in Australia, with larger records unconfirmed. Females are much smaller than males, with typical female body lengths in the range of 7 to 9 feet (2.5 metres). The saltwater crocodile has fewer armor plates on its neck than other crocodilians, and its broad body contrasts with most other lean crocodiles, leading to early unverified assumptions the reptile was an alligator.

Saltwater crocodiles are severely depleted in numbers throughout the vast majority of their range, with sightings in areas such as Thailand, Cambodia, Laos and Vietnam becoming extremely rare and the species may in fact even be extinct in one or more of these countries. With that said, it is also the least likely of crocodilians to become globally extinct due to its wide distribution and almost pre-colonial population sizes in Northern Australia and New Guinea. In India this crocodile is extremely rare in most areas but is very common in the north eastern part of the country (mainly Orissa and the Sunderbans). The population is sporadic in Indonesia and Malaysia with some areas harboring large populations (Borneo for example) and others with very small, "at risk" populations (the Philippines). The saltwater crocodile is also present in very limited portions of the South Pacific, with an average population in the Solomon Islands, a very small & soon to be extinct population in Vanuatu (where the population officially only stands at three) and a decent but at-risk population in Palau (possibly rebounding).

Saltwater crocodiles have earlier prevailed as far west as the east coast of Africa at the Seychelles Islands, and all the way up the coast of Africa . These crocodiles were once believed to be a population of Nile crocodiles, but they were later proven to be Crocodylus porosus.

Saltwater crocodiles generally spend the tropical wet season in freshwater swamps and rivers, moving downstream to estuaries in the dry season, and sometimes traveling far out to sea. Crocodiles compete fiercely with each other for territory, with dominant males in particular occupying the most eligible stretches of freshwater creeks and streams. Junior crocodiles are thus forced into the more marginal river systems and sometimes into the ocean. This explains the large distribution of the animal (ranging from the east coast of India to northern Australia) as well as it being found in odd places on occasion (such as the Sea of Japan, for instance). Saltwater crocodiles can swim 15 to 18 miles per hour in short bursts, but when cruising can go 2 to 3 miles.

African Lion

The lion (Panthera leo) is a member of the family Felidae and one of four "big cats" in the genus Panthera. Reaching 272 kg (600 lb), it is the second-largest cat after the tiger. They currently exist in the wild in sub-Saharan Africa and in Asia with a critically endangered remnant population in northwest India, having disappeared from North Africa, the Middle East and western Asia in historic times. Until the late Pleistocene (about 10,000 years ago), the lion was the most widespread large land mammal beside man. They were found in most of Africa, much of Eurasia from western Europe to India and the Bering land bridge and in the Americas from Yukon to Peru.

Lions live for approximately 10–14 years in the wild, while in captivity they can live 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 lion pride consists of related females and offspring and a small number of dominant males. Groups of female lions typically hunt together, preying mostly on large ungulates. The lion is an apex and keystone predator, though 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% 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 18th century. Zoos are cooperating worldwide in breeding programs for the endangered Asiatic subspecies.

The male lion is highly distinctive and is easily recognized by its mane. The lion, particularly the face of the male, is one of the most widely recognized 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 historically occurred. It has been extensively depicted in literature, in sculptures, in paintings, on national flags, and in contemporary films and literature.

The lion's name, similar in many languages, derives from the Latin leo, and before that the Ancient Greek le?n/????. The Hebrew word lavi (??????) may also be related, as well as the Ancient Egyptian rw. It was one of the many species originally described, as Felis leo, by Linnaeus in his 18th century work, Systema Naturae. The generic component of its scientific designation, Panthera leo, is often presumed to derive from Greek pan- ("all") and ther ("beast"), but this may be a folk etymology. Although it came into English through the classical languages, panthera is probably of East Asian origin, meaning "the yellowish animal," or "whitish-yellow".

Great White Shark

The great white shark, Carcharodon carcharias, also known as white pointer, white shark, or white death, is an exceptionally large lamniform shark found in coastal surface waters in all major oceans. Reaching lengths of about 6 metres (20 ft) and weighing up to 2,250 kilograms (5,000 lb), the great white shark is the world's largest known predatory fish. It is the only surviving species of its genus, Carcharodon.

Carolus Linnaeus gave the great white shark its first scientific name, Squalus carcharias in 1758. Sir Andrew Smith gave it the generic name Carcharodon in 1833, and in 1873 the generic name was identified with Linnaeus specific name and the current scientific name Carcharodon carcharias was finalised. Carcharodon comes from the Greek words karcharos, which means sharp or jagged, and odous, which means tooth.

The great white is classified as a mackerel (Lamnidae) shark. There are four other living species in this family, two mako and two Lamna sharks.

Dental features and the extreme size of both the great white and the prehistoric Megalodon lead many scientists to believe they were closely related, and the name Carcharodon megalodon was applied to the latter. At present there is considerable doubt about this hypothesis, and other scientists would place the megalodon and white shark as distant relatives - sharing the family Lamnidae but no closer relationship.

Megalodon is only known from its teeth and from a few cartilage remains, and probably reached sizes of 12 m (39 ft) or more, considerably larger than even the largest great white sharks. From time to time it is suggested that megalodon might still exist. Megalodon teeth have supposedly been found from as recently as 10,000 to 12,000 years ago, but these results appear to be based on misinterpretation of the evidence. However, while megalodon fossils are widespread and plentiful, no evidence has surfaced that the species is anything but extinct.

Other evidence suggests that the great white shark is more closely related to the mako shark than to the megalodon. According to this theory, Carcharodon orientalis[verification needed] and the broad tooth mako Isurus hastalis are fossil sharks that are considered ancestral to the great white. The Carcharocles and Otodus obliquus sharks are in this case considered the ancient representatives of the extinct megalodon lineage; indeed, Carcharocles megalodon is a popular alternative classification of the megalodon.

Great white sharks live in almost all coastal and offshore waters which have a water temperature of between 12 and 24° C (54° to 75° F), with greater concentrations off the southern coasts of Australia, off South Africa, California, Mexico's Isla Guadalupe and to a degree in the Central Mediterranean and Adriatic Seas. One of the densest known populations is found around Dyer Island, South Africa where much research on the shark is conducted. It can be also found in tropical waters like those of the Caribbean and has been recorded off Mauritius.

It is a pelagic fish, but recorded or observed mostly in coastal waters in the presence of rich game like fur seals, sea lions, cetaceans, other sharks and large bony fish species. It is considered an open-ocean dweller and is recorded from the surface down to depths of 1,280 m (4,199 ft), but is most often found close to the surface.

In a recent study great white sharks from California were shown to migrate to an area between Baja California and Hawaii, where they spend at least 100 days of the year before they migrate back to Baja. On the journey out, they swim slowly and dive down to around 900 m (2,953 ft). After they arrive, they change behaviour and do short dives to about 300 m (984 ft) for up to 10 minutes. It is still unknown why they migrate and what they do there; it might be seasonal feeding or possibly a mating area.

In a similar study a great white shark from South Africa was tracked swimming to the northwestern coast of Australia and back to the same location in South Africa, a journey of 20,000 km (12,428 mi) in under 9 months.

Australian Box Jellyfish

Box jellyfish are water-dwelling invertebrates belonging to the class Cubozoa, named for their cube-shaped medusae. They share many characteristics with their relatives the true jellies in the class Scyphozoa. The name sea wasp is also applied to some species of cubozoans, including Chironex fleckeri and Carybdea alata.

Box jellies are found in Australia, the Philippines, and many other tropical areas. They are known for the often-fatal effects of their venom, although not all species are dangerous to humans. One box jelly species is the most venomous animal in the world.

Box jellies use powerful venom contained in epidermic nematocysts, a structure exclusive to stinging cnidarians, to stun or kill their prey prior to ingestion, or as an instrument for defense. Their venom is the most deadly in the animal kingdom and has caused at least 5,567 recorded deaths since 1884. Most often, these fatal envenomations are perpetrated by the largest species of box jelly, Chironex fleckeri, owing to its high concentration of nematocysts, though at least two deaths in Australia have been attributed to the thumbnail-sized irukandji jellyfish (Carukia barnesi). Those who fall victim to Carukia barnesi suffer several severe symptoms known as Irukandji syndrome.

The venom of cubozoans is very distinct from that of scyphozoans, and is used to catch prey (fish and small invertebrates) and for defense from predators. Sea turtles, however, are apparently unaffected by the sting and eat box jellies.

In the Australian summer from November to April or May, box jellyfish are abundant in the warm waters of northern Australia and drive away most swimmers. However, they generally disappear during the Australian Winter. Australian researchers have used ultrasonic tagging to learn that these creatures sleep on the ocean floor between 3 pm and dawn. It is believed that they sleep to conserve energy and to avoid predators.

Some theorize box jellies actively hunt their prey—for effective hunting they move extremely quickly (at speeds up to 3 to 3.5 knots (1.5 to 1.8 m/s)) instead of drifting as do true jellyfish. They are known to be the only jellyfish with an active visual system, consisting of 24 eyes located on the center of each side of its bell.

The eyes occur in clusters on the four sides of the cube-like body. Sixteen are simply pits of light-sensitive pigment (eight slit-shaped eyes and eight lens-less pit eyes), but one pair in each cluster is surprisingly complex, with a sophisticated lens, retina, iris and cornea, all in an eye only 0.1 millimeters across.

The lenses on these eyes have been analyzed and could form distortion free images. Despite the perfection of the lenses, the retinas of the eyes lie closer to the lens than the optimum focal distance, resulting in a blurred image. One of these eyes in each set has an iris that contracts in bright light. Four of the eyes can only make out simple light levels.

It is not currently known how this visual information is processed by Cubozoa, as they lack a central nervous system, although they seem to have four brain-like organs.

Asian Cobra

Naja naja is a species of venomous snake native to the Indian subcontinent. It is the most famous of the Big Four, the four most poisonous snakes of India for which a single polyvalent antivenom has been created. Like other cobras, N. naja is famous for its threat display involving raising the front part of its body and spreading its hood. This snake is revered in Indian mythology and culture and is often seen with snake-charmers. It is now protected in India under the 1972 Indian Wildlife Protection Act (1972).

On the rear of this hood are two circular ocelli patterns connected by a curved line, evoking the image of spectacles. An average cobra is about 1 meter in length and rarely as long as 2 meters (6 feet). The spectacle pattern on the hood is very variable as also the ground colour of the snake.

The Oriental Ratsnake Ptyas mucosus is often mistaken for the cobra; however this snake is much longer and can easily be told apart by the stronger ridged appearance of its body. Other snakes which resemble Naja naja are the Banded Racer Argyrogena fasciolata and the Indian Smooth Snake Coronella brachyura.

Naja naja is found throughout the mainland of India (excluding the Northeast). It is also found in Sri Lanka, Pakistan, Nepal, Bhutan and Bangladesh. It ranges from sea-level upto 2000m.

Cobras normally feed on rodents, toads, frogs, birds and snakes. Their normal habitat includes open forest and farmland. They are however also able to thrive in cities, living on rodents in the sewers and underground drains.

Indian cobras are oviparous and lay their eggs between the months of April and July. Females lay from 12 to 30 eggs in a underground nest and the eggs hatch 48 to 69 days later. Newborns cobras measure between 8 and 12 inches (20-30 cm). Newly hatched cobras have fully functional glands.

In India, the spectacled cobra is much respected and feared, and even has its own place in Hindu mythology as a powerful deity. The Hindu god Shiva is often depicted with a protective cobra coiled around his neck. Vishnu, the preserver of the universe, is usually portrayed as reclining on the coiled body of Sheshnag, the Preeminent Serpent, a giant snake deity with multiple cobra heads. Cobras are also worshipped during the Hindu festival of Nag Panchami.

There are numerous myths about cobras in India, including the idea that they mate with ratsnakes.

The Indian cobra's celebrity comes from its popularity as a snake of choice for snake charmers. The cobra's dramatic threat posture makes for a unique spectacle as it appears to sway to the tune of a snake charmer's flute. Snake charmers with their cobras in a wicker basket are a common sight in many parts of India. The cobra, of course, is deaf to the snake charmer's pipe, but follows the visual cue of the moving pipe and it can sense the ground vibrations from the snake charmer's tapping foot.

In the past Indian snake charmers also conducted cobra and mongoose fights. These gory fight shows, in which the snake was usually killed, are now illegal. The mongoose is not known to have any immunity to the venom, but its agility and thick fur helps overcome most snakes.

Mosquito

The mosquitos are insects which make up the family Culicidae. They have a pair of scaled wings, a pair of halteres, a slender body, and long legs. The females of most mosquito species suck blood (hematophagy) from other animals, which has made them one of the most deadly disease vectors known to man, killing millions of people over thousands of years and continuing to kill millions per year by the spread of diseases.

Length varies but is rarely greater than 16 mm (0.6 inch), and weight up to 2.5 mg (0.04 grain). A mosquito can fly for 1 to 4 hours continuously at up to 1-2 km/h travelling up to 10 km in a night. Most species are nocturnal or crepuscular (dawn or evening) feeders. During the heat of the day most mosquitos rest in a cool place and wait for the evenings. They may still bite if disturbed.

Mosquitoes are believed to have evolved around 170 million years ago during the Jurassic era (199–144 million years ago) with the earliest known fossils from the Cretaceous era (144–65 million years ago). They are thought to have evolved in South America, spreading initially to the northern continent Laurasia and re-entering the tropics from the north. Some ancestral mosquitos were about three times the size of the extant species.

The family Culicidae, a sister group to the Chaoboridae (biting midges), belongs to the order Diptera and contains about 3,500 species in three subfamilies: Anophelinae (3 genera), the Culicinae (at least 37 genera and >80% of all the species) and the Toxorhynchitinae (1 genus). The genera include Anopheles, Culex, Psorophora, Ochlerotatus, Aedes, Sabethes, Wyeomyia, Culiseta, and Haemagoggus. Within the subfamily Anophelinae six subgenera are recognized: Stethomyia, Lophopodomyia, Kerteszia, Nyssorhynchus (all South American), Cellia (Old World only), and Anopheles (worldwide).

Both male and female mosquitos are nectar feeders, but the female is also capable of haematophagy (drinking blood). Females do not require blood for survival, but they do need supplemental protein for the development and laying of their eggs. Prior to sucking the blood, they inject a mild painkiller, which numbs the host to the pain from the "bite" (Note: mosquitos do not actually bite). The Toxorhynchites species of mosquito never drinks blood. This genus includes the largest of the extant mosquitos, the larvae of which are predatory on the larvae of other mosquitos. These mosquito eaters have been used in the past as mosquito control agents, with varying success .

In the Spanish language, the word Mosquito (little fly) dates back to about 1572. The word was adopted to replace the term "biting flies" to prevent confusion with the house fly. It is derived from the word fly (Latin musca, cf. Skt maksh) and is related to the Italian moschetta and the French moustique. Mosquitoes were originally called "les moucherons" or "les cousins" by French writers, "Stechm?cken" or "Schnaken" by Germans, "mygg" and "mygga" by Scandinavians, and "?????" (konops) by the ancient Greeks. The Scandinavian word is related to the Modern Greek word "????" (myga) for the housefly, and to the English "midge". The Icelandic "m?" mostly stands for biting midges or non-biting chironomids, as there are no mosquitos in Iceland. Aristotle referred to mosquitoes in 300 B.C. as "empis".