Crows and ravens are some of the smartest animals on the planet. So what do you know about them?

What do you know about your kidneys? They don't get the acclaim of the brain or the heart, but these small organs work nonstop to keep your body healthy.

Let's see how well you know your own species' family tree.

Test your knowledge about frogs and toads with this quiz.

You go to the beach to relax and soak up the sun. But how much do you really know about the waves and the sand?

How much do you know about these ancient shelled reptiles?

Want to delve inside someone's subconscious? Graphology might hold a key.

Before you scoop up your next bowl of ice cream, test your knowledge about everyone's favorite summer treat.

They help you see the world, but how much do you really know about the windows to your soul? Test your knowledge.

Can you live without your morning coffee or afternoon soda? See how savvy you are about your daily buzz.

When your head hits the pillow at night, do creatures lurk? See how much your know about terrifying dreams.

There's a whole medicine chest in the garden. Do you know which plants to use for what ailments? Test your holistic herb wits here.

How much do you really know about the ground under your feet? Test your knowledge with this quiz.

These iconic pink birds are immediately recognizable, but how much do you know about them? Test your knowledge of these beautiful birds!

Life across the globe depends on bees, butterflies, birds, bats and other pollinators. Test your knowledge about these vital creatures.

From spring showers to summer thunderstorms, rain can fall any time of year. But how does it work?

Bison have been named our new national mammal. Test your knowledge of this species that's so critical to North America's ecology.

These unusual creatures are stunningly beautiful and surprisingly important to life on Earth. Show us what you know!

Sheep provide us with meat, clothing and even scientific illumination, but how much do you know about them? Find out with this quiz.

Test your knowledge of all things autumnal.

Bacteria live everywhere in your body, including your gut. These microbes have quite an impact on your health. Do you know what they do?

Whether it's a white lie or a whopper, fibs are part of our daily lives. We like to think we're honest but, well, we're not. Test your falsehood expertise.

Whether you're crying tears of joy or crying over spilled milk, how much do you really know about the tears rolling down your face?

Lightning is more than just a stunning spectacle. Take our quiz to see how much you really know about this electrifying natural wonder.

Think you know everything about that special day of scary movies and sugar highs? Test your Halloween smarts ... if you dare.

When the going gets tough, some animals get going — to bed. Take our hibernation quiz to see how much you know.

The Sustainable Energy Coalition lists 7 facts about the growing green jobs sector.

A dramatic film explores the physical and emotional challenges of living in a peak oil scenario.

From Buckingham Palace to the BBC, British institutions are putting the kibosh on single-use plastic.

For the media, exonerated climate scientists aren't nearly as interesting as evil, manipulative ones.

Timing matters: Flowers bloom, insects emerge, birds migrate, and planting and hunting seasons are carefully coordinated times in order to take advantage of wha

Do energy vampires haunt your living room? Find out if you are electricity-savvy with your entertainment devices.

Famed naturalist and conservationist John Muir was so much more than the father of our national parks.

A video capturing the screech-filled feud has gone viral.

A trip to Costa Rica reminds the author of the chemicals you avoid when buying organically grown products.

Chanie Kirschner helps an expectant mom focus on the things she can control.

Delightfully fizzy and well-flavored, these kombucha sodas are a healthy choice.

What is Lyme disease? Here's where you are more likely to get it and the symptoms to look for if you're concerned.

The fast-food chain is becoming increasingly sustainable with vegetarian fare and natural, cage-free meat options.

We treat it like it's as 'routine as poutine,' but 'misteaks' will come back and bite us in the rump roast.

In honor of Cesar Chavez Day, here are 10 interesting facts about the civil rights activist.

Humans and house spiders go way back, yet we rarely give this relationship much thought. Here's what to know about your arachnid roommates.

By 2050, New Zealand hopes to be rid of rats, possums, stoats and other invasive predators.

As Obama plans for an energy makeover, his Department of Energy is still focused on nuclear weapons.

Even if you take the energy and water it takes to build a dishwasher into account, it still beats washing by hand.

More than half of the world's largest aquifers are being depleted, according to satellite system data.

State legislators in Colorado are working to make it legal for residents to harvest rainwater for irrigation.

From their vanilla-scented secretions to their amazing ability to alter an ecosystem, here's what you need to know about beavers.

It all depends on the upcoming rainy season and residents maintaining water conservation restrictions.

In June 2012, a network of 16,000 computers trained itself to recognize a cat by looking at 10 million images from YouTube videos.