The male humpback whale is believed to sing its mysterious songs mainly for the same reason generations of teenage boys have started bad garage bands: to get girls.
Researchers had thought the ocean crooners serenaded their women only during their winter mating season in the tropics. Now, scientists know the humpbacks also break out in song during springtime in New England, the time and place they’re supposed to be focused on eating.
The findings, gathered by observing humpbacks roaming feeding grounds off Cape Cod, undermine long-held assumptions about humpback behavior, said whale biologist Phillip Clapham of the Northeast Fishery Sciences Center, co-author of a paper on the singing in the current issue of Proceedings Royal Society, Biology.
“It tells us whales don’t read the textbooks, which is really annoying,” he said.
The whales haven’t suddenly taken to a new stage off the Cape, said Cornell University professor Christopher W. Clark, a bioacoustics expert and the paper’s co-author.
“I’m sure they were doing it,” Clark said. “We just never listened.”
Looking for Mr. Right Whale
Clark and Clapham had hoped to hear the chatty, rare and hard-to-track North Atlantic right whale when they began recording in an area of Georges Bank, about 80 nautical miles (150 kilometers) east of the Cape, between May and June 2000.
Instead, they heard almost nothing but humpbacks singing.
“They’re supposed to be singing down in the Caribbean, where guys are on the corner and the girls are out in short skirts,” he said. “They’re not supposed to be singing at suppertime.”
The singing Clark heard and the sporadic humpback sounds he expected to hear are as different as a grunt at the dinner table and a grand opera.
Humpbacks have a range that covers eight octaves, from a bass so low that humans can’t hear it to a magnificent soprano, Clark said. Their highly structured songs include multiple themes that are constantly repeated and even rhyme.
The songs last up to 30 minutes, and the whales embellish like jazz musicians, seeing “who can improvise in some attractive way better than the other (whale),” Clark said.
Aside from attracting mates, singing is also believed to establish a hierarchy among male humpbacks. Some theorize the singing breaks out among migrating whales as they start to mix.
Raging whale hormones?
Clapham said the whales could be singing because their hormone levels are still high from winter. Or they could be establishing bonds with females in hopes of hooking up during the next mating season, he said.
They also might be trying to immediately mate with females who didn’t conceive the previous winter, he said. Whaling catch data indicates humpbacks have been conceived outside of the winter mating season, even though it’s rare for females to ovulate then.
More study is needed on the humpbacks, which are an endangered but recovering species, with an estimated 11,500 in the North Atlantic. Clapham said in the end the spring singing may just be a chance for “low-cost advertising” — the male humpback is eating and there are females around, so he might as well give it a shot, mating season or not.
“Males take any opportunity they can to attract the females, across the animal kingdom,” he said.