The Brazilian beverage giant Cia.

While Red Bull on the rocks isn't exactly poised to eclipse the Cosmopolitan, the energy drink has become big enough that even the beverage giants have noticed.

Since the beverage giants dominated the shelf space in supermarket and convenience stores, Nantucket Nectars salesmen begged mom-and-pop stores to stock their bottles.

Analysts say it faces formidable challenges, including the risk that consumers will tire of juice potions and the certainty of stiff competition from the beverage giants.

It also has a wide assortment of public relations firms, proxy solicitors and other takeover specialists to advise it how to fend off the British food and beverage giant.

In the past, such other beverage giants as Pepsico and Anheuser-Busch have been mentioned as prospective suitors.

Suntory Ltd., one of Japan's beverage giants, wants no thirst unquenched.

The beverage giants are also trying to break out of their traditional strongholds to inhabit as many kinds of outlets as possible.

While they battle one another, the beverage giants cannot leave their flanks unprotected.

While the beverage giants bring big budgets and sheer marketing power, most of the new energy drinks are being dreamed up by small outfits operating with much narrower margins.