Environment

Every rush hour, bumper-to-bumper traffic belches out diesel fumes along Madrid's Gran Via, a six-lane artery that bisects the Spanish capital. Art Deco facades line the grand boulevard.

But they're blackened with soot.

"The pollution hurts my eyes, and I can feel it in my throat," says commuter María Villallega, 48, who lives in the city center and walks to work. "I don't own a car myself, and I'll be happy when they're not allowed here anymore. We need to protect the planet, and ourselves."

This story starts with the mystery of a missing cow.

University of Utah researchers placed seven cow carcasses in Utah's Great Basin Desert, and set up cameras to learn about the behavior patterns of local scavengers.

But a week later, researcher Evan Buechley returned to one of the sites and found no sign of the cow.

A rain forest sings with the sounds of insects, birds, maybe a howler monkey or two. But scientists are discovering that some forest dwellers also communicate in ways humans usually can't hear — via ultrasound.

A team from Dartmouth College has recorded these signals in treetops on a pristine Panamanian island called Barro Colorado, and slowed them down to make sense of them.

Earlier this winter, photographer Michael Furtman was driving along the North Shore of Lake Superior in search of great gray owls. Several of the giant, elusive birds had flown down from Canada looking for food.

He pulled off on a dirt road where he had seen an owl the night before. An owl was there, perched in a spruce tree, but a pair of videographers were filming it.

"I backed off; I was going to just let them have their time with the bird," Furtman says. "And then I saw them run out and put a mouse on the snow."

This weekend bicycles are ruling the road in Yellowstone National Park. Most park roads are closed until later this month, but every spring Yellowstone opens about 50 miles of its main thoroughfares to bikes only.

Humans have long looked to animals for design inspiration. From basic camouflage to a quiet bullet train in Japan to the Wright brothers' wings, the process called biomimicry is a basic tenet of human engineering.

Jonathon Keats has turned it on its head.

For the second consecutive year, Japanese whalers have returned to port after an Antarctic expedition with the carcasses of 333 whales. The five-ship fleet, put forth by the country's Fisheries Agency, killed the minke whales during a months-long voyage to southern waters for what it calls ecological research.

As California water officials confirmed Thursday that the snowpack in the Sierra Nevada remains well above average, pressure was mounting on the state to lift emergency water restrictions that have been in place for two years.

The snowpack across the mountains is now 164 percent of average, a closely watched marker in the nation's most populous state — and biggest economy — where one-third of all the drinking water comes from snow-fed reservoirs.

Driving up the coast toward Bay Center, Wash., it's obvious when you start to approach Willapa Bay. Fifteen-foot high piles of empty shells begin to appear on the side of the road. This is an oyster town.

But it's also home to a sinking piece of history.

When President Trump signed an order to roll back climate policies, he promised more jobs for coal miners.

"My administration is putting an end to the war on coal. Gonna have clean coal, really clean coal," Trump said in making the announcement at the Environmental Protection Agency headquarters Tuesday.

After millions of dollars of flood damage and mass evacuations this year, California is grappling with how to update its aging flood infrastructure. Some say a natural approach might be part of the answer.

All the water that poured down spillways at the Oroville Dam in northern California did a lot of damage to the area — and for miles down the river.

"It looks like a bomb's gone off," says John Carlon of River Partners, a nonprofit that does river restoration. "That's what it looks like."

Update 7:06 P.M. Eastern: The EPA says it's reversing course and keeping chlorpyrifos on the market.

That's despite the agency's earlier conclusion, reached during the Obama administration, that this pesticide could pose risks to consumers. It's a signal that toxic chemicals will face less restrictive regulation by the Trump administration.

Canyon Mansfield and his dog were walking the ridge line near his house in Pocatello, Idaho, when the 14-year-old spotted a curious device that looked like a sprinkler nestled in the ground.

U.S. nuclear energy company Westinghouse Electric has filed for Chapter 11 bankruptcy protection, citing massive cost overruns in the construction of four nuclear power reactors in the U.S.

Westinghouse, a subsidiary of Japanese conglomerate Toshiba, says it has secured $800 million in financing as it goes through a "strategic restructuring." But that's just a fraction of the billions in losses it's expected to rack up this year.

President Trump issued a sweeping executive order on Tuesday that will begin to undo a slew of government efforts to fight global warming.

Among those worrying and watching to see how the executive order plays out are scientists who actually are in favor of exploring bold interventions to artificially cool the climate.

In 2008, candidate Barack Obama ran an ad with this opening line: "The hands that built this nation can build a new economy. The hands that harvest crops can also harvest the wind."

And then it showed men working on roofs: "The hands that install roofs can also install solar panels."

President Trump signed a sweeping executive order Tuesday that takes aim at a number of his predecessor's climate policies.

The wide-ranging order seeks to undo the centerpiece of former President Obama's environmental legacy and national efforts to address climate change.

It could also jeopardize America's current role in international efforts to confront climate change.

In a symbolic gesture, Trump signed the document at the headquarters of Environmental Protection Agency.

Primate brains may have grown larger and more complex thanks to a fruit-filled diet, a new study suggests.