Christopher Joyce

Some of the weirdest animal behavior is about romance. That's especially true with birds — they croon or dance or display brilliant feathers to seduce the reluctant.

This sort of sexual display apparently has a long pedigree: There's now new evidence that some dinosaurs may have used the same come-on.

The source is a kind of dinosaur that was built like a 400-pound ostrich. It lived about 75 million years ago and is called ornithomimus, meaning "bird mimic."

If you're reading this blog, you're probably into food. Perhaps you're even one of those people whose world revolves around your Viking stove and who believes that cooking defines us as civilized creatures.

Well, on the latter part, you'd be right. At least according to some neuroscientists from Brazil.

Whales are among the great communicators of the animal world. They produce all sorts of sounds: squeaks, whistles and even epic arias worthy of an opera house.

And one whale in particular has apparently done something that's never been documented before: He imitated human speech.

The beluga, or white whale, is smallish as whales go and very cute, if you're into marine mammals. Belugas are called the "canaries of the sea" because they're very vocal.

Few things are as rare as a piece of rock that falls from outer space and crashes onto Earth.

Among the most prized of these meteorites are from Mars. Friday, scientists describe the latest one discovered: It's called Tissint, and this weekend you can buy a piece of it.

The Pacific Island of Guam is experiencing a population explosion — of spiders.

There are more spiders there now than anyone can remember. To get a sense of how weird the situation is, I started out in Maryland. On my front porch, overlooking the Severn River.

At 6:30 in the morning on a cool fall day, I find two spider webs in a matter of five minutes. But if I were on the island of Guam, I might find 70 or 80 spider webs in five minutes.

Anthropologists believe early humans evolved in Africa and then moved out from there in successive waves. However, what drove their migrations has been a matter of conjecture.

One new explanation is climate change.

Anthropologist Anders Erikkson of Cambridge University in England says the first few hardy humans who left Africa might've gone earlier but couldn't. Northeastern Africa — the only route to Asia and beyond — was literally a no man's land.

That fake fruit in the wooden bowls that hotels love to decorate their lobbies with never looks quite right. No, apparently it takes nature to make a fake that looks even better than the real thing.

Transcript

STEVE INSKEEP, HOST:

Just to keep us up to date here on Hurricane Isaac, it's become a tropical storm and forecasters expect to downgrade it to a tropical depression by this evening. That is small comfort, though, to people facing the storm's strong winds and heavy rains. States as far north as Ohio could feel Isaac's effects.

DAVID GREENE, HOST:

Last of a five-part series

The droughts that have parched big regions of the country are killing forests.

In the arid Southwest, the body count is especially high. Besides trying to keep wildfires from burning up these desiccated forests, there's not much anyone can do. In fact, scientists are only now figuring out how drought affects trees.

Fourth in a five-part series

Forests in the Southwest have become a fuel stockpile. A century of U.S. Forest Service policy of quashing all fires has allowed forests to become overgrown, and now a warming climate is making the problem worse.

Scientists are trying to defuse these green time bombs. Is it too late?

Third of a five-part series

As the Earth's average temperature creeps upward, climate scientists have predicted record heat waves and droughts. That's what we've seen this summer in the U.S.

The question has become, are we now seeing the real damage climate change can do?

Second of a five-part series

Fire scientists are calling it "the new normal": a time of fires so big and hot that no one can remember anything like it.

One of the scientists who coined that term is Craig Allen. I drive with him to New Mexico's Bandelier National Monument, where he works for the U.S. Geological Survey. We take a dirt road up into the Jemez Mountains, into a landscape of black poles as far as you can see.

First of a five-part series

The history of fire in the American Southwest is buried in a catacomb of rooms under the bleachers of the football stadium at the University of Arizona.

Here rules professor Thomas Swetnam, tree ring expert. You want to read a tree ring? You go to Tom. He's a big, burly guy with a beard and a true love for trees.

Second of a two-part series. Read Part 1.

Modern architecture's love affair with tall glass buildings takes a toll. Every year, millions of birds crash into glass windows in North America.

These collisions may seem like an intractable problem. But in New York City, an architect is trying to find a solution.

First of a two-part series. Read Part 2.

Modern architecture loves glass. Glass makes interiors brighter and adds sparkle to cityscapes. But glass also kills millions of birds every year when they collide with windows. Biologists say as more glass buildings go up, more birds are dying.

The last couple of years have certainly felt unusually hot in many parts of the U.S., but are they really all that unusual?

Many people wonder whether a warming climate is turning up the temperature or whether it's all just part of the normal variation in the weather. Among scientists, there's a growing view that these latest heat waves are indeed a result of climate change.

Some of the most interesting discoveries in archaeology come from sifting through ancient garbage dumps. Scientists working in Oregon have found one that has yielded what they say are the oldest human remains in the Americas and a puzzle about the earliest American tools.

Early Americans used Oregon's Paisley Caves for, among other things, a toilet. Little did they know that scientists would be picking through what they left behind.

The famous paintings on the walls of caves in Europe mark the beginning of figurative art and a great leap forward for human culture.

But now a novel method of determining the age of some of those cave paintings questions their provenance. Not that they're fakes — only that it might not have been modern humans who made them.

The first European cave paintings are thought to have been made over 30,000 years ago. Most depict animals and hunters. Some of the eeriest are stencils of human hands, apparently made by blowing a spray of pigment over a hand held up to a wall.