While searching for information about bad breath in whales, I e-mailed University of Hawaii whale expert Joe Mobley to see what he knew about the subject. Joe didn’t know of any link between whales’ well-known halitosis and illness (a theory), but he did know something about how whales and dolphins amuse themselves.

In a paper published in the June issue of the journal Aquatic Mammals, Mobley and his colleagues report two remarkable incidents, one off Kauai in 2004 and the other off Maui in 2006. Each time, a humpback whale and bottlenose dolphin seemed to be playing together.

In the Kauai event, eight bottlenose dolphins were swimming ahead of two humpback whales along the Kekaha coastline. As the research boat approached the dolphins to take identification photos, two dolphins turned, swam to the whales and rode the pressure wave made by one whale’s head.

This is common. Bottlenose dolphins (and others) are famous for hitching rides on the bow waves of several species of whales as well as boats. Such surfing allows the dolphins to swim forward with less effort, but because dolphins often leave their pods and race toward whales and boats to catch these waves, they don’t seem to be conserving energy. Rather, most researchers agree, the animals are playing.

When looking down on these bow riders from a boat deck, it’s hard to imagine they’re doing anything else. Their cavorting, spinning and leaping looks like joyful fun. One bottlenose that recently rode my sailboat’s bow wave repeatedly flipped onto its back and rode upside-down, showing us its creamy pink belly.

The Kauai dolphins took their surfing a step further when, one at a time, they positioned their bodies sideways over the whale’s snout. When one dolphin lay lengthwise on its side, the whale stopped swimming and slowly raised its head, lifting the unresisting dolphin from the water. As the humpback’s huge head kept rising, the dolphin arched its body and balanced over the end of the whale’s snout.

When the whale was nearly vertical, with its eye at the water’s surface, the dolphin used the head as a slide, slipping into the water tail first. Then off it went to join the waiting dolphin, and they porpoised back to the pod.

In the Maui incident off Mala Wharf, the whale, a female with calf, lifted a dolphin in the same manner six times. After the dolphin swam away, the mother also lifted her calf on her snout.

Lifting in whales and dolphins is also common. The air-breathing mammals often support their young or an injured individual at the surface, even helping species other than their own. Some dolphins have behaved like Lassies of the sea, supporting and escorting distressed humans to safety.

The dolphins in this report, though, were healthy-looking, high-energy individuals, neither ill nor frightened. The whales and dolphins, the researchers cautiously conclude, were simply playing.

During this summer of almost daily bad news about the ocean, this report is a sweet breath of fresh air. Unless, of course, you’re downwind of an exhaling whale. But that’s another column.

Susan Scott can be reached at www.susanscott.net.