Humpback Whales: The Song Heard Round the World
Humans have always been fascinated by whales. Haven’t you? But marveling at their massive size and amazing beauty was just the beginning. The more scientists learn about them the more amazing they seem.
Humpback whales (Megaptera novaeangliae) are ocean Olympians, swimming thousands of miles in a grand feat of endurance each year. As you can see in this infographic, each ocean basin is home to one or two populations. They travel to survive, and where you’ll find them depends on the season.
Humpbacks alternate between winter in the tropics and summer near the poles. In winter, the whales spend time in balmy tropical climates. Usually seeking some shelter in the shallower seas along a coastline, the warm, clear water is perfect for mother whales to give birth and nurse their calves. But the tropics can’t sustain the whales forever. The reason the water looks clear is that it contains very little nutrients or plankton, so there is nothing for the whales to eat there.
When summer comes, the humpbacks are hungry and they embark on the long migration to more nutrient-rich polar waters. They’ll spend all summer at the feeding grounds – and they have to eat a lot because they’ll need to survive the whole winter with little or no food! Eventually, though, the poles will get too cold and they’ll return back to the tropics to do it all again.
Researchers Jim Darling and Meagan Jones listen to whale songs recorded through an underwater microphone.
The details are different for each population: Humpbacks that spend winter in Hawaii travel about 3,000 miles (4828 km) to Alaska to feed. The ones that spend winter near Costa Rica migrate to south of Cape Horn. If swum in a straight line, that’s about 4500 miles (7242 km) making it the longest known migration of any mammal! There also is one group of humpbacks that doesn’t migrate. The population found in the Arabian Sea seems to have everything it needs right there, year round, so they stay put.
As impressive as these migrations are, the peak of human amazement by the great humpback whale came from a different discovery: the moment we discovered that they sing.
Male humpbacks hang in the water with their tail up and head down and produce long, elaborate melodies. A song can last 20 minutes, but the whale may keep singing for hours on end. All of the males within a population sing the same song, and each year the song changes a little, with a new song spreading from group to group. It’s not entirely known why they do it, but it may have something to do with wooing females (females can make sound but they don’t sing like the males do). Their song can be heard underwater for miles around so a male whale can impress lots of potential mates, or maybe intimidate lots of competitors.
It can be said that humpback whales connect the world. Their migrations link diverse places like Tonga and Antarctica, or Greenland and the Caribbean – places that may seem to have little in common besides a shared group of annual whale visitors. Their melancholy song has inspired people all over the globe to listen, to notice, and to care. Surely with the next great discovery about these mystical mammals, they will just continue to amaze us.