Biology
The Knee: Connecting Your Leg Bones
The knee is the hinge joint that connects the main bones of the leg (the femur and the tibia). The kneecap (patella) lies over the front of the joint. There are strong ligaments on both sides of the joint, called the medial and lateral collateral ligaments. There are also two ligaments within the joint, called [...]
Toucan: Distinguishing Bills
The toucan is a bird that lives in the rain forests of North America and South America. Each brightly colored animal has a long bill that is unique in color pattern, which helps the birds to distinguish one another. These long bills are useful in getting at small fruits and berries, although toucans also eat [...]
Whooping Crane: Spectacular Dancers
Unique to North America, whooping cranes (“Grus americana”) stand about five feet tall, have sinewy necks, long legs, and a wing span of about seven-and-a-half feet. Their snow-white bodies are contrasted by jet-black wing tips and a red-and-black head.
Blue Whale: Largest Animal Ever
It is believed that no animal — living or dead — has ever been larger than the blue whale. This giant marine mammal can grow up to 120 feet in length and weigh more than 100 tons. Like other large undersea animals, the blue whale reaches its massive size by feeding on microscopic animals known [...]
Incomplete Metamorphosis: Can't Wait Til I Get My Wings
Cockroaches and grasshoppers, among many, go through incomplete metamorphosis. When cockroaches and grasshoppers hatch, they look like tiny replicas of their parents except for two important differences: They cannot reproduce yet and they lack functional wings. At this stage, they are called nymphs. The stage preceding each molt is known as an instar. Every time [...]
Grasshoppers: Making a Summer Song
In late summer, the fields buzz with the singing of male grasshoppers inviting female grasshoppers to court. Rubbing their back legs against their wings, each species sings its own song. After mating, the female grasshopper lays 2 to 120 eggs in the soil, dying soon afterward. However, throughout the winter the eggs remain carefully hidden [...]
Fossils: How They're Formed
66 Million BC Everything we know about dinosaurs comes from studying the fossils they left behind. Not every animal or plant that died in the distant past created a fossil. Usually, whatever was left of a dead animal was eaten by scavengers or gradually dissolved into the earth by the forces of air and water. [...]
Moths: We’re Different from Butterflies!
What’s the difference between butterflies and moths? Many moths and butterflies look alike. But a few traits help us to distinguish one from the other. The butterfly has club-like antennae, while moth antennae are feathery or hair-like. Butterflies are usually brighter in color than moths. Butterflies have slim bodies compared to the moth’s stout, hairier [...]
Triceratops: Rhinoceros of Dinosaurs
70 Million BC30 Feet11 Tons With its mighty three-horned head and heavily armored body, a fast-charging Triceratops must have been a fearsome sight to any hungry Tyrannosaurus. Certainly not what you would call an easy meal.
Pteranodon: The Flying Reptile
75 Million BC23 Feet37 Pounds Pteranodon belongs to an ancient group of flying reptiles called "pterosaurs" that lived at the same time as the dinosaurs. When the first pterosaur fossils were discovered in Germany in 1784, scientists thought they were aquatic animals. It took them 100 years to finally recognize they were flying reptiles!