• A cockroach can live for 9 days without its head.It only dies when it cannot eat.


• A crocodile's tongue is attached to the roof of its mouth and cannot move it. So, a crocodile cannot stick out its tongue. The scales of a crocodile are made of ceratin, the same substance that hooves and fingernails are made of.


• A dragonfly has a life span of 24 hours.


• A goldfish has a memory span of three seconds.


• A snail can sleep for three years. A snail has two pairs of tentacles on its head. One pair is longer than the other and houses the eyes. The shorter pair is used for smelling and feeling its way around.


• African elephants only have four teeth to chew their food with.


• Animals are either right-handed or left-handed. Polar bears are left-handed.


• An ant can lift 50 times its own weight, can pull 30 times its own weight and always falls over on its right side when intoxicated.


• An ostrich's eye is bigger than its brain.


• Butterflies taste with their feet.


• Cats have over one hundred vocal sounds. Dogs only have about 10. A cat has 32 muscles in each ear.


• Cats, camels and giraffes are the only animals in the world that walk right foot, right foot, left foot, left foot, rather than right foot, left foot


• Dogs: There are 701 types of pure breed dogs. The oldest breed of dog is the Saluki. The world's smallest dog is the Chihuahua, which means "tiny dog in the sky." There are about 54 million dogs in the US, and Paris is said to have more dogs than people. The coyote is a member of the dog family and its scientific name, "canis latrans" means barking dog.


• Male mosquitoes are vegetarians. Only females bite and suck blood.


• Sharks are immune to all known diseases. A shark is the only fish that can blink with both eyes. It is impossible to out-swim a shark - sharks reach speeds of 70 km/h (44 mph). Humans can run about 35 km/h (21 mph).


• Starfish don't have brains.


• The heart of a blue whale is the size of a small car. The tongue of a blue whale is as long as an elephant.


• There are more than 150 million sheep in Australia, a nation of 17 million people. New Zealand is home to 4 million people and 70 million sheep.


• Tigers have striped skin, not just striped fur.


• Turtles can breathe through their butts.

• 1. Box Jellyfish
  
  
  The Box Jellyfish has caused at least 5,567 recorded deaths since 1954.
  
  Their venom is among the most deadly in the world, and it attacks the heart, nervous system, and skin cells. It causes an overpowering pain that human victims go in shock, drown or die of heart failure very quickly. Survivors may experience pain for weeks after being stung by the box jellyfish.
  
  Treatment for for the venomous sting of a jellyfish has to be carried out immediately. Vinegar should be applied for a minimum of 30 seconds on the affected area. Vinegar has acetic acid, which helps to neutralize the poison (nematocysts).
  
  Wearing panty hose while swimming in the water where box jellyfish is known to exist may help to prevent legs from being stung by the box jellyfish. Box Jellyfish can be found in the waters around Asia and Australia.



• 2. King Cobra
  
  
  The King Cobra (Ophiophagus hannah) is the world's longest venomous snake, growing up to 5.6 m (18.5 ft) in length. Ophiophagus, literally means snake-eater as it eats other snakes. One single bite of this deadly snake can easily kill a person. This snake is capable of killing a full-grown Asian elephant within 3 hours of being bitten.
  
  The King Cobra can inject 5 times more venom than a black mamba, resulting in death 5 times faster than that of the black mamba. King cobra is found in the highland forest of South and Southeast Asia.



• 3. Marbled Cone Snail
  
  
  The Marbled Cone snail is so deadly that one drop of its venom can kill more than 20 persons.
  
  The Marbled Cone snail may be found in warm salt water. One can be poisoned by it just by picking it up with your bare hand, resulting in intense pain, swelling, numbness and tingling. In severe cases, muscle paralysis, vision changes and breathing failure. These symptoms may be take immediate effect or may be delayed for days. No anti-venom is yet available for treatment.



• 4. Blue-Ringed Octopus
  
  
  The Blue-Ringed Octopus is as big as a golf ball, but its venom is so powerful that it can kill a human being. Its poison can kill up to 26 adult persons within minutes.
  
  Its bite is painless, but the deadly neurotoxins begin working immediately resulting in muscular weakness, numbness, followed by cessation in breathing and ultimately death. No antidote is yet available.
  
  They can be found in tide pools in the Pacific Ocean, from Japan to Australia.



• 5. Death Stalker Scorpion
  
  
  The Death Starker Scorpion is highly poisonous. Its venom is a powerful cocktail of neurotoxins which causes an intense pain, then fever, followed by a coma, convulsions, paralysis and death. Fortunately, while a sting from this scorpion is extremely painful, it may not kill a healthy, adult person. Young children, the old, or the infirm (with a heart condition) are at biggest risk.
  
  Death stalker scorpions are found in North Africa and the Middle East .
  
  
• 6. Stonefish
  
  
  Stonefish is the most venomous fish in the world. Its venom can cause such a severe pain that the victims of its sting want the affected limb to be amputated. It is described as the worst pain known to man. It may be accompanied by shock, paralysis, and tissue death. If not given medical attention within a couple of hours, it can be fatal.
  
  Stonefish stores its toxins in its gruesome-looking spines that are designed to hurt would-be predators.
  
  Stonefish are found in waters north of the Tropic of Capricorn, often in the shallow tropical waters of the Pacific and Indian oceans, between the Red Sea and the Queensland Great Barrier Reef.



• 7. The Brazilian wandering spider
  
  
  The Brazilian Wandering Spider (Phoneutria) or banana spider appears in the Guinness Book of World Records 2007 as the most venomous spider and as the spider responsible for most human deaths.
  
  This spider is believed to have the most potent neurotoxic venom of all spiders. Only 0.006mg (0.00000021oz) of the vernom is sufficient to kill a mouse.
  
  The Brazilian Wandering Spider often hide during daytime in highly populated areas inside houses, clothes, boots, and cars. Its venomous bite can cause not intense pain as well as priapism - uncomfortable erection lasting for many hours leading to impotence.



• 8. Inland Taipan
  
  
  The Inland Taipan is a very poisonous snake of Australia . Just a single bite from this snake contains enough venom to kill 100 adults or an army of 250,000 mice. Its venom is at least 200 - 400 times more toxic than a common cobra. Its neurotoxic venom can kill an adult in as little as 45 minutes.



• 9. Poison Dart Frog
  
  
  If you ever happen to be running through the rain forests somewhere in Central or South America , do not pick up beautiful and colorful frogs. It can be the Poison Dart Frog.
  
  This frog is probably the most poisonous animal on earth. The 2 inch long (5cm) golden poison dart frog has enough venom to kill 10 adults or 20,000 mice. Only 2 micrograms of this lethal toxin (the amount that fits on the head of a pin) is capable of killing a person.
  
  They are called dart frogs because indigenous Amerindians use of their toxic secretions to poison the tips of their blow-darts..
  Poison dart frogs keep their poison in their skins and can sicken or kill anybody who touches or eats it.



• 10. Puffer Fish
  
  
  Puffer Fish are the second most poisonous vertebrate on earth (the first one is golden dart Frog).
  
  The meat of some species is a delicacy in both Japan (as fugu) and Korea (as bok-uh) but the problem is that the skin and certain organs of many puffer fish are very poisonous to human beings.
  
  This puffy fish produce rapid and violent death. Puffers poisoning causes deadening of the tongue and lips, dizziness, vomiting, rapid heart rate, difficulty breathing, and muscle paralysis. Victims die from suffocation as diaphragm muscles are paralyzed. Most of the victims die after four to 24 hours.
  
  There is no known antidote. Most deaths from fugu happen when untrained people catch and prepare the fish. Since Fugus poison can cause near instantaneous death, only licensed chefs are allowed to prepare it.
  Statistics show that there were 20 to 44 incidents of fugu poisoning per year between 1996 and 2006 in all of Japan and up to six incidents per year led to death.

Introduction
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing.

Forty percent of mammal species are rodents, and they are found in vast numbers on all continents other than Antarctica. Common rodents include mice, rats, squirrels, chipmunks, gophers, porcupines, beavers, hamsters, gerbils, guinea pigs, degus, chinchillas, prairie dogs, and groundhogs. Rodents have sharp incisors that they use to gnaw wood, break into food, and bite predators. Most eat seeds or plants, though some have more varied diets. Some species have historically been pests, eating seeds stored by people and spreading disease.

Size and range of order
In terms of number of species—although not necessarily in terms of number of organisms (population) or biomass—rodents make up the largest order of mammals. There are about 2,277 species of rodents (Wilson and Reeder, 2005), with over 40 percent of mammalian species belonging to the order. Their success is probably due to their small size, short breeding cycle, and ability to gnaw and eat a wide variety of foods.

Rodents are found in vast numbers on all continents except Antarctica, most islands, and in all habitats except oceans. They are the only placental order, other than bats (Chiroptera) and Pinnipeds, to reach Australia without human introduction.

Characteristics
Many rodents are small; the tiny African pygmy mouse can be only 6 cm (2.4 in) in length and 7 g (0.25 oz) in weight at maturity, and the Baluchistan Pygmy Jerboa is of roughly similar or slightly smaller dimensions. On the other hand, the capybara can weigh up to 80 kg (180 lb), and the largest known rodent, the extinct Josephoartigasia monesi, is estimated to weigh about 1,000 kg (2,200 lb), and possibly up to 1,534 kg (3,380 lb)or 2,586 kg (5,700 lb).

Rodents have two incisors in the upper as well as in the lower jaw which grow continuously and must be kept worn down by gnawing; this is the origin of the name, from the Latin rodere, to gnaw. These teeth are used for cutting wood, biting through the skin of fruit, or for defense. The teeth have enamel on the outside and exposed dentine on the inside, so they self-sharpen during gnawing. Rodents lack canines, and have a space between their incisors and premolars. Nearly all rodents feed on plants, seeds in particular, but there are a few exceptions which eat insects or fish. Some squirrels are known to eat passerine birds like cardinals and blue jays.

Members of non-rodent orders such as Chiroptera (bats), Scandentia (treeshrews), Insectivora (moles, shrews and hedgehogs), Lagomorpha (hares, rabbits and pikas) and mustelid carnivores such as weasels and mink are sometimes confused with rodents.

Importance to humans
Rodents have lived on the planet for at least 56 million years and modern humans for less than one million, but the consequences of their interactions during that short overlap of evolutionary time have been profound. For rodents, early humans were just another predator to avoid, but with Homo sapiens’ transition from nomadic hunting and gathering to sedentary agricultural practices, humans became a reliable source of shelter and food for those species having the innate genetic and behavioral abilities to adapt to man-made habitats. The impact of these species upon human populations ranges from inconvenient to deadly. Crops are damaged before harvest; stored food is contaminated by rodent waste; water-impounding structures leak from burrowing; and objects are damaged by gnawing. Certain species are reservoirs for diseases such as plague, murine typhus, scrub typhus, tularemia, rat-bite fever, Rocky Mountain spotted fever, and Lassa fever, among others. Only a few species are serious pests or vectors of disease (see house mouse and rat), but it is these rodents that are most closely associated with people.

Various other rodents are beneficial, providing a source of food through hunting and husbandry (see cavy, cane rat, bamboo rat, paca, capybara, and woodchuck), apparel derived from their fur (see nutria and chinchilla), test animals for biomedical and genetic research (especially mice and rats), pleasure as household pets (see golden hamster, guinea pig, and gerbil), and insight on mammalian biology and evolutionary history.

Evolution
The fossil record of rodent-like mammals begins shortly after the extinction of the non-avian dinosaurs 65 million years ago, as early as the Paleocene. Some molecular clock data, however, suggest that modern rodents (members of the order Rodentia) already appeared in the late Cretaceous, although other molecular divergence estimations are in agreement with the fossil record. By the end of the Eocene epoch, relatives of beavers, dormouse, squirrels, and other groups appeared in the fossil record. They originated in Laurasia, the formerly joined continents of North America, Europe, and Asia. Some species colonized Africa, giving rise to the earliest hystricognaths. From Africa hystricognaths rafted to South America, an isolated continent during the Oligocene and Miocene epochs. By the Miocene, Africa collided with Asia, allowing rodents such as the porcupine to spread into Eurasia. During the Pliocene, rodent fossils appeared in Australia. Even though marsupials are the prominent mammals in Australia, rodents make up almost 25% of the mammals on the continent. Meanwhile, the Americas became joined and some rodents expanded into new territory; mice headed south and porcupines headed north.