Agriculture
Got Milk? How?
New Gene Fights Potato Blight
Watching out for vultures
Amphibians
Bullfrogs
Toads
Tree Frogs
Animals
Missing Moose
Thieves of a Feather
Hot Pepper, Hot Spider
Behavior
How Much Babies Know
Calculating crime
Taking a Spill for Science
Birds
Macaws
Parakeets
Hummingbirds
Chemistry and Materials
Watching out for vultures
Big Machine Reveals Small Worlds
Popping to Perfection
Computers
Fingerprint Evidence
Graphene's superstrength
The Shape of the Internet
Dinosaurs and Fossils
Meet your mysterious relative
Downsized Dinosaurs
Tiny Pterodactyl
E Learning Jamaica
2014 GSAT Results for Jamaican Kids
E Learning in Jamaica WIN PRIZES and try our Fun Animated Games
Results of GSAT are in schools this week
Earth
Shrinking Glaciers
Slip Slidin' Away—Under the Sea
Meteorites may have sparked life on Earth
Environment
Pumping Up Poison Ivy
The Oily Gulf
Food Web Woes
Finding the Past
Stone Age Sole Survivors
Digging Up Stone Age Art
Stonehenge Settlement
Fish
Sturgeons
A Grim Future for Some Killer Whales
Parrotfish
Food and Nutrition
Moving Good Fats from Fish to Mice
Yummy bugs
Symbols from the Stone Age
GSAT English Rules
Adjectives and Adverbs
Capitalization Rules
Order of Adjectives
GSAT Exam Preparation Jamaica
GSAT Practice Papers | GSAT Mathematics | Maths
E Learning in Jamaica WIN PRIZES and try our Fun Animated Games
42,000 students will sit for the GSAT Exam in two weeks
GSAT Exams Jamaica Scholarships
GSAT Scholarship
42,000 students will sit for the GSAT Exam in two weeks
Results of GSAT are in schools this week
GSAT Mathematics
Secrets of an Ancient Computer
10 Common Mistakes When Preparing for the GSAT Math Test
Setting a Prime Number Record
Human Body
Speedy Gene Gives Runners a Boost
Sea Kids See Clearly Underwater
Disease Detectives
Invertebrates
Lobsters
Butterflies
Tarantula
Mammals
Felines
Rottweilers
Grizzly Bear
Parents
How children learn
Choosing a Preschool: What to Consider
What Not to Say to Emerging Readers
Physics
The Pressure of Scuba Diving
Echoes of a Stretched Egg
Electric Backpack
Plants
Fastest Plant on Earth
Fast-flying fungal spores
The algae invasion
Reptiles
Gila Monsters
Copperhead Snakes
Rattlesnakes
Space and Astronomy
A Great Ball of Fire
A Smashing Display
Burst Busters
Technology and Engineering
Riding Sunlight
Are Propellers Fin-ished?
Toy Challenge
The Parts of Speech
What is a Preposition?
Adjectives and Adverbs
Countable and Uncountable Nouns
Transportation
Are Propellers Fin-ished?
Charged cars that would charge
Troubles with Hubble
Weather
Earth's Poles in Peril
Warmest Year on Record
A Change in Climate
Add your Article

Mammals in the Shadow of Dinosaurs

Dinosaurs spent 170 million years on Earth before they suddenly died out about 65 million years ago. After dinosaurs disappeared, mammals took over. It turns out that small mammals lived during the reign of dinosaurs, too. And over the last few years, a flurry of new discoveries has revealed what these creatures were like. They were not the pathetic, little creatures that scientists had previously imagined. In fact, these mammals were well-adapted to their habitats, and they survived alongside dinosaurs quite well. Last year, for example, researchers looked at the remains of a chipmunk-like creature that lived 150 million years ago. Fossils included a lower jaw, skull fragments, and 40 percent of a skeleton. Based on their size, shape, and arrangement, the animal's foot and limb bones indicate that it did a lot of digging. It's the first animal of that era shown to have this type of behavior. Also last year, paleontologists analyzed two skeletons of a type of predator that belonged to the genus Repenomamus. These mammals lived in China about 130 million years ago. One species of Repenomamus is the largest mammal yet discovered from the dinosaur age. It measured 1 meter (3.3 feet long) and weighed up to 14 kilograms (31 pounds). It looked like a badger. Another species of Repenomamus was about the size of an opossum. One specimen was found with the remains of a baby dinosaur in its stomach (see "Dino Takeout for Mammals"). "These are spectacular discoveries," says Jason A. Lillegraven, a paleontologist at the University of Wyoming in Laramie. "They show a degree of diversification [of early mammals] that we hadn't recognized before." The most recent addition to the growing list of ancient mammals is called Castorocauda lutrasimilis, which means "beaver-tailed creature that looks like an otter." It lived about 164 million years ago in northeastern China. At 50 centimeters (19.7 inches) long, Castorocauda was about the size of a platypus. It probably weighed some 800 grams (1.8 pounds). That's more than 10 times heavier than other mammals living at that time. Castorocauda's remains include the oldest fossilized fur yet found. Its body was covered by a thick layer of fur underneath an outer coat of long, stiff guard hairs. Like modern beavers, leathery scales and guard hairs covered the creature's tail, which probably helped it swimThe animal's back teeth were shaped like the teeth of modern seals and were useful for both biting and grinding food. Like seals, it probably ate fish and invertebrates that lived in the water. Until recently, most evidence that scientists had of these unique mammals came from fossilized teeth. While plentiful and well-preserved, teeth can reveal only so much. Future finds should help scientists piece together the history of mammalian evolution, both during the time of dinosaurs and beyond.—E. Sohn

Mammals in the Shadow of Dinosaurs
Mammals in the Shadow of Dinosaurs








Designed and Powered by HBJamaica.com™