Whales ordinarily come into view only briefly, when they part the ocean's shimmer to breathe. Humpbacks, though more active at the surface than most, still spend about 90 percent of their lives below. What are they doing down there? They roam too widely through rough and remote seas for scientists to follow; it's no wonder the ways of whales, Earth's grandest life-forms, are still steeped in mystery. But out in the wonderfully clear, blue, warm waters of the 'Au'au Channel, investigators have been gathering new clues about a crucial part of the whales' lives: courtship and birth.
Observers from the Whale Trust, a Maui-based foundation for research and education, have found that some of the submerged males are calling out the humpback's famous song, filling the seas with strange and lovely incantations. Some of the females are tending new calves as they pile on dozens of pounds daily and, in a year, double their length on their mothers' rich milk. What no one fully grasped until recently was how many other submerged humpbacks are not cruising, not singing or nursing, but simply hanging out.
"The more we searched, the more humpbacks we found just drifting along with the current at a mile or two an hour, 30 to 80 feet (9 to 24 meters) deep," says photographer Flip Nicklin, a longtime marine mammal observer. "Now when I look out across the channel, I picture this river of whales flowing by, hidden from ordinary view."
They don't seem to be eating either, even though many have migrated 2,500 miles (4,000 kilometers) or more from feeding grounds off Alaska and British Columbia and have a long return journey ahead. Some speculate that the whales roam farther offshore to at least snack now and then, but people who watch humpbacks every day see nary a poop. The animals are apparently living off the layers of blubber beneath their skin. You can do that if you're as huge as a humpback: The ability to gulp prodigious quantities of food and store fat by the ton frees the animals to travel long distances and concentrate on other vital behavior for weeks or months at a time.
The whales hanging out below don't even bother much with breathing. Instead of coming up every 10 to 15 minutes for a series of breaths as busier humpbacks do, they stay down for half an hour or so, scarcely moving a muscle. "We call them breathholders," Nicklin says. They may be conserving energy for more important activities on the winter range, namely romance.
"Crucifix block," observes Dan Salden, head of the Hawaii Whale Research Foundation, another Maui-based group, which studies humpback social behavior. He's standing on the prow of his boat, Deep Blue, describing a male that has risen vertically almost halfway out of the water and spread its long, winglike pectoral fins to either side, forming the shape of a cross. The move cuts off one of the 10 or 11 other males racing behind from getting any closer to the prize: a female, swimming just ahead of the pack.
Lifting his tape recorder again, Salden announces, "Peduncle throw." A different male swimmer has just whipped the whole muscular, tapering rear of its body—the peduncle, which powers the fluke—high in the air. It causes the animal's front end to swing straight downward, forcing a male that had been hot on its tail to dive to avoid a collision.