Hurricanes Katrina and Rita inundated Louisiana marshes with salt water, and a subsequent drought means that the waters have stayed too salty for gators to comfortably reproduce.

This week: Pluto not a planet, "Atlantis" eruption update, jellyfish invasion, ant speed record, interview with Kilimanjaro's quickest conqueror, more.

A celebrity orca barked just like a sea lion, scientists say, proving that killer whales have the rare ability to learn and produce new sounds. With audio

The recent discovery of a fox carcass has prompted fears that invasive foxes have established a foothold in the Australian state of Tasmania, an island renowned for its large areas of pristine wilderness.

It's a record in the animal kingdom: The trap-jaw ant catapults to safety by snapping its jaws at an astonishing 145 miles (233 kilometers) an hour, scientists say.

A year after Hurricane Katrina, new laws and big shelters are cropping up nationwide to better accommodate pets during a disaster. But so are lawsuits over the storm's pet refugees.

Go behind the scenes as conservationists release a captive-bred giant panda into China's bamboo-covered mountains for the first time.

Huge hordes of jellyfish are plaguing Mediterranean beaches, stinging tens of thousands of vacationers. Experts blame the invasion on warming seas and overfishing of the jellies' competitors.

This week: Interview with Snakes on a Plane wrangler, snake threat helped eyes evolve, ancient embryos x-rayed, U.S. lags behind in acceptance of evolution, more.

Two plants planned in the U.S. Midwest will produce millions of gallons of ethanol using power derived from the area's most abundant but least appreciated resource.

The largest shipment of contraband ivory ever seized comes entirely from savanna elephants from the southern African country.

Boaters on the Suwannee River are having close encounters with curious creatures—giant Gulf sturgeon that leap out of the water for reasons scientists don't understand.

Having recovered from extinction in Sweden and Norway, the gray wolf's future is now threatened by political backlash as rural communities lobby for relaxed protections for the predator.

Watch as a lone male bird tries to steal a meal from another family's turf and winds up locked with another male in a whirling dive bomb.

A bizarre fossil found in Australia suggests that baleen whales weren't always gentle giants—an ancient ancestor with sharp serrated teeth likely hunted sharks and other fish.