If a worker ant attempts to reproduce in the presence of the queen, the worker inadvertently produces a chemical that causes her sisters to attack.

How giant reptiles got off the ground; extinct beasts that could walk again; an algae-fueled jet takes flight.

Call it "ovulation on demand"—a bizarre male bark jump-starts a female cheetah's reproductive system, adding a much-needed boost to breeding the rare big cats in captivity, experts say.With audio.

Two Australian tourists were killed when giant chunks of ice slid off New Zealand's Fox Glacier. The brothers had ventured into an off-limits zone.

The discovery could solve the cosmic chicken-and-egg riddle of which came first—galaxies or the supermassive black holes nestled in their cores.

Up and down California's coast, brown pelicans are dying in alarming numbers, and sick and disoriented pelicans have been found wandering on roads and in other unusual places—and scientists are stumped.

Like the wakes of cosmic speedboats, oddly shaped bow shocks reveal single stars careening through the cosmos at more than 112,000 miles (180,250 kilometers) an hour.

Among the surprises scientists have in store for the coming year: Sunken treasures, a new evolution debate, earlier Earths, and a host of revelations about the universe.

Medical imaging tools used to peer inside living people have been adapted to create the first virtual fly-though of the remains of a dead star.