HANOI, Vietnam: Nguyen Huong Giang loves to party but loathes hangovers, so she ends her whiskey benders by tossing back shots of rhino horn ground with water on a special ceramic plate.

Her father gave her the 4-inch (10-centimeter) brown horn as a gift, claiming it cures everything from headaches to cancer. Vietnam has become so obsessed with the fingernail-like substance that it now sells for more than cocaine.

Experts say Vietnam's surging demand is threatening to wipe out the world's remaining rhinoceros populations, which recovered from the brink of extinction after the 1970s thanks to conservation campaigns.

Illegal killings in Africa hit the highest recorded level in 2011 and are expected to worsen this year.