Agriculture
Making the most of a meal
Watering the Air
Earth-Friendly Fabrics
Amphibians
Frogs and Toads
Bullfrogs
Poison Dart Frogs
Animals
Red Apes in Danger
Odor-Chasing Penguins
Killer Flatworms Hunt with Poison
Behavior
Meet your mysterious relative
Reading Body Language
Night of the living ants
Birds
Tropical Birds
Cardinals
Ducks
Chemistry and Materials
Makeup Science
Putting the Squeeze on Toothpaste
Sugary Survival Skill
Computers
Fingerprint Evidence
Two monkeys see a more colorful world
Games with a Purpose
Dinosaurs and Fossils
Battling Mastodons
Dinosaurs Grow Up
Dinosaur Dig
E Learning Jamaica
Results of GSAT are in schools this week
2014 GSAT Results for Jamaican Kids
E Learning in Jamaica WIN PRIZES and try our Fun Animated Games
Earth
Plastic-munching microbes
What is groundwater
Getting the dirt on carbon
Environment
Fungus Hunt
Plant Gas
Saving Wetlands
Finding the Past
A Long Trek to Asia
A Big Discovery about Little People
A Plankhouse Past
Fish
Barracudas
Salmon
Cleaning Up Fish Farms
Food and Nutrition
Packing Fat
Strong Bones for Life
Sponges' secret weapon
GSAT English Rules
Pronouns
Subject and Verb Agreement
Capitalization Rules
GSAT Exam Preparation Jamaica
March 21-22, 2013: Over 43,000 students will take the GSAT Exam
GSAT Exam Preparation
Scotiabank Jamaica Foundation Grade Six Achievement Test (GSAT) Scholarships
GSAT Exams Jamaica Scholarships
GSAT Practice Papers | GSAT Mathematics | Maths
GSAT Exam Preparation
2014 GSAT Results for Jamaican Kids
GSAT Mathematics
Secrets of an Ancient Computer
GSAT Practice Papers | GSAT Mathematics | Maths
Detecting True Art
Human Body
Speedy Gene Gives Runners a Boost
Heavy Sleep
Heart Revival
Invertebrates
Butterflies
Roundworms
Praying Mantis
Mammals
Poodles
Numbats
Cats
Parents
Raise a Lifelong Reader by Reading Aloud
Children and Media
Choosing a Preschool: What to Consider
Physics
Spin, Splat, and Scramble
Extra Strings for New Sounds
Thinner Air, Less Splatter
Plants
Stalking Plants by Scent
City Trees Beat Country Trees
A Giant Flower's New Family
Reptiles
Box Turtles
Crocodilians
Cobras
Space and Astronomy
Return to Space
Pluto's New Moons
Supernovas Shed Light on Dark Energy
Technology and Engineering
Supersuits for Superheroes
Slip Sliming Away
A Clean Getaway
The Parts of Speech
Pronouns
What is a Verb?
Problems with Prepositions
Transportation
Seen on the Science Fair Scene
Robots on a Rocky Road
Middle school science adventures
Weather
Antarctica warms, which threatens penguins
A Dire Shortage of Water
Watering the Air
Add your Article

Rodents

Found across almost the entire globe, rodents have learned to thrive in deserts, grasslands, and especially around human settlements, where some species (like mice and rats) have become common pests. Humans keep some rodents as pets, but even wild ones (such as squirrels and chipmunks) have learned to live in harmony with us in the city and suburbs. Although usually thought of as small -- with the more common species being small enough to hold in your hands -- there are others, like the Capybara, which can grow to the size of small dog. In terms of number of species (though not necessarily in terms of number of organisms–population–or biomass) rodents make up the largest order of mammals, with over 40 percent of mammalian species belonging to the order. There are between 2000 and 3000 species of rodents, which are found in vast numbers on all continents except Antarctica (they are the only placental order other than bats, Chiroptera, to reach Australia without human introduction), most islands, and in all habitats except for oceans. Most rodents are small; the tiny African pygmy mouse is only 6 cm in length and 7 grams in weight. On the other hand, the capybara can weigh up to 45 kg (100 pounds) and the extinct Phoberomys pattersoni is believed to have weighed 700 kg. 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, and dent, tooth. 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 even fish. Rodents are important in many ecosystems because they reproduce rapidly, and can function as food sources for predators, mechanisms for seed dispersal, and as disease vectors. Humans use rodents as a source of fur, as model organisms in animal testing, for food, and even in detecting landmines. 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 for rodents. The fossil record of rodents began after the extinction of the dinosaurs 65 million years ago. By the end of the Eocene epoch, beavers and squirrels appeared in the fossil record. They originated in Laurasia, the joined continents of North America, Europe, and Asia. Some species colonized Africa, giving rise to the earliest hystricognaths. From there they rafted to South America, an isolated continent during the Oligocene and Miocene epochs. By the Miocene, Africa collided with Asia, allowing rodents such as porcupines 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.

Rodents
Rodents








Designed and Powered by HBJamaica.com™