Despite its low numbers, the North Atlantic right whale may not be the rarest of all the great whales. There may be no more than a few hundred North Pacific right whales, Eubalaena japonica, which were harpooned illegally by Soviet whalers as late as the 1960s. But on the other side of the Equator, the southern right whale, Eubalaena australis, has rebounded from a few hundred in the 19th century to at least 10,000. If its cousins along North America's East Coast are the urban whales, these giants of the Southern Hemisphere are the wild whales, and they offer a vision of what a safer future might be like for the other two right whale species.

After feeding in plankton-laden waters around Antarctica, the various populations of E. australis migrate to wintering areas near Argentina, southern Africa, western and southern Australia, and sub-Antarctic New Zealand. The species has been increasing at a rate of up to 7 percent annually. That's close to the maximum possible for whales that require a full year for pregnancy, devote at least one more to nursing, and another to fatten up, and therefore can produce an offspring only every third year.

In July 2007 Rolland, Kraus, and I joined a team bound for the Auckland Islands, 300 miles south of New Zealand through some of the planet's stormiest latitudes, to carry out census and DNA work. As our 82-foot sailboat Evohe slipped into a protected bay amid the isles, there was nothing but sunshine washing the deck. Then, like explorers of a bygone era, we watched natives paddle across the water to surround our vessel. Except these natives paddled with flukes and blew spray from their heads.

Curious right whales investigated Evohe for hours while yellow-eyed penguins leaped along like skipping stones beside them. Great breaths overrode the sounds of waves and seabird cries and the mewling of young New Zealand sea lions from rookeries ashore. More whales milled and breached for as far as we could see. They were bigger than northern rights. More than one in ten were pinto-patterned, flashing yards of smooth white skin. A bygone era? This was beginning to feel more like the dawn of creation. Rolland and Krause, who had never viewed a southern right before, were beside themselves.

"Omigod. That one right there is the fattest young whale I have ever seen." (When judging the condition of northern rights, the scientists pay special attention to the area just behind the blowhole, where the chubbier animals develop a bulge of blubber. Its size has proved to be an accurate predictor of survival.) "We don't even have a category for a whale with a fat roll that big."