By Valerie Shore, naturalist
They’re acrobats, marathon travellers, singing virtuosos, passionate lovers and versatile eaters. Oh, and they’re also interfering busybodies.
These are just a few of the ways to describe humpback whales—the largest marine mammals we regularly see on whale watching tours from Victoria.
Now through the fall is the peak time of year to see humpbacks in the Salish Sea. So, in celebration of these charismatic giants, here are 9 things that may surprise you about the whale known as Megaptera novaeangeliae (big-winged New Englander):
Humpback breach! / Photo by Valerie Shore, Eagle Wing Tours
- They’re big. Really big.
In terms of size, think of a city transit bus and add a massive tail and two long pectoral flippers. If you’re talking weight, make that two city transit buses. That’s 40 tons and more than 50 feet of whale. Everything about them is huge. The average humpback heart, for example, weighs about 430 lb.—as much as three adult humans!
That tail we mentioned? Up to 18 ft. wide. And those pectoral flippers? About 15 ft. or a third of the body length. No other whale has pectoral flippers anywhere near that long. If you look straight down at a humpback whale in the water, those massive flukes and wing-like pectoral flippers make it look like a large passenger jet!
- They’re marathon travellers.
Humpback whales really have things figured out. In the late spring, summer and fall they eat with gusto in nutrient-rich temperate seas such as coastal BC. Their sole purpose is to get as fat as possible. In the winter, they head south to tropical seas—places like Mexico and Hawaii—where they live off that stored blubber and focus entirely on romance. Sounds good to us. Except for the not eating part.
To live this double life, humpback whales undertake one of the longest migrations of any mammal, with some individuals making a round trip of 10,000 miles in a single year. To put that in perspective, that’s almost twice the width of Canada!
Humpbacks lunge-feeding. / Photo by Brendon Bissonnette, Eagle Wing Tours
- They’re eating machines. Part one.
Humpbacks eat food that’s tiny compared to their own hulking mass. To bulk up fast you have to eat lots of it—up to 3,000 lb. a day. Which is why they’re superbly adapted for feeding on big balls of food, such as zooplankton, krill and small schooling fish.
As a baleen whale (no teeth here!), humpbacks have up to 400 fringed overlapping baleen plates hanging from each side of their upper jaw. They also have up to 35 throat pleats stretching from lower jaw to belly. To eat, a whale raises its upper jaw at an almost 90-degree angle, its throat pleats expand like an accordion, and in goes a massive gulp of food and water—roughly equivalent to a 15,000-gallon backyard swimming pool.
The whale then uses its tongue to squeeze the water out through the baleen plates and, voilà, a mouthful of yummy whale food!
Humpback feeding, showing distended throat pleats. / Photo by Brendon Bissonnette, Eagle Wing Tours
- They’re eating machines. Part two.
But wait. There’s more to the story. When the food is balled up, the whales typically lunge-feed—surfacing on their side, mouths agape and throats distended like a bullfrog. But food doesn’t always obligingly ball up. So what’s a humpback to do? Easy peasy. You get creative.
For example, there’s trap-feeding, a behaviour documented for the first time in 2011, where the whale hangs stationary at or just below the surface, mouth fixed wide open. Fish unwittingly meander into the new shady “pool” to get away from nearby diving birds. Down comes the upper jaw!
Or there’s bubble-netting. Seen in southeast Alaska and northern BC, this spectacular behaviour involves a group of humpbacks working together as a team. One whale blows a ring of bubbles below the fish to contain them. Another whale dives deep and bellows a loud feeding call. Then all the whales surface within the bubble “net,” mouths agape and teeming with fish!
- They’re virtuoso singers.
Whales don’t have vocal chords. Instead they make sounds internally by squeezing air through sinuses and connecting passageways. It’s a pretty neat trick, especially for male humpbacks, who as it turns out are crooners extraordinaire.
Humpback whales sing some of the longest and most complex songs in the animal kingdom. When scientists sent a Voyager spacecraft hurtling into our solar system and beyond in 1977, guess what they sent as greetings from Earth, in addition to 60 human languages?
Sure, when you first listen to these songs they sound like a bunch of random whines, squeals and grunts. But they’re not random. At the breeding grounds, all males in a population sing the same song, sometimes for up to 30 minutes, repeating themes and phrases in a particular order. Each population’s song is different and changes slightly over time.
Who are these whales singing to? Scientists remain puzzled. It doesn’t seem to be the girls because only males seem drawn to investigate. It’s not territorial because the curious males sometimes join in or spiral around each other and move off together. One intriguing theory—it’s a recruitment tool for roaming males to team up for a common cause. See #7.
Upside down breach! / Photo by Karac Lindsay, Eagle Wing Tours
- They’re incredible acrobats.
Very little in the animal kingdom matches the sheer awe of seeing a 40-ton leviathan hurtle out of the water in a full breach. It’s the pièce de résistance in the humpback’s playbook of surface antics, which include pectoral fin slapping, tail-lobbing, chin-slapping, cartwheeling and spyhopping. Little wonder that Herman Melville, author of Moby Dick, called them “the most gamesome and light-hearted of all the whales.”
Why do they do these things? After all, it takes a lot of energy to hurl yourself around like that. Maybe it’s those itchy barnacle hitchhikers—one whale can have up to 1,000 ib. of them attached to its skin. Maybe it’s a way to communicate with other humpbacks near and far. Or maybe—and this one gets our vote—they do it because they can and it’s fun!
Whatever the reason, it’s an astonishing display of strength and joie de vivre—two or three swipes of that powerful tail muscle (called a peduncle) and wheeee, you’re airborne!
Humpbacks fluking. / Photo by Clint Rivers, Eagle Wing Tours
- They’re hot-blooded lovers.
Humpbacks have been dubbed “the gentle giants of the sea.” Whoever came up with that hadn’t seen the boys in action at the breeding grounds. Gentle it’s not. At the centre of all the fuss, of course, is a female. She usually has a male escort whose main job is to wait patiently for his lady friend to give him an encouraging sign, if you know what we mean.
Trouble is, there are other boys in town, each with the same idea. So when a group of eager bachelors encounters a female and escort, the fireworks begin. Multiple testosterone-fueled giants plunge through the waves in pursuit of the female, jostling, ramming, tail-slashing and head-butting each other to usurp the escort and be the chosen one for fatherhood.
Many mature male humpbacks bear the scars of these epic jousting matches—known as heat runs—with gouges, rips and bloody tubercles (the wart-like bumps on the head) from collisions with their barnacle-encrusted opponents. But there’s a happy ending. Almost one year later, the result is a one-ton, 15-foot long bundle of joy.
Humpback mother and calf. / Photo by Valerie Shore, Eagle Wing Tours
- They’re doting mothers.
Here’s where the term “gentle giant” is accurate. Humpback mothers are devoted single parents. Like all mammals, they nurse their babies with milk, in this case 46-60 per cent fat—about the consistency of sour cream. Young calves drink roughly 600 litres of milk a day and put on about 5 lb. per hour. Think about that the next time you open the fridge!
Even more remarkable is that mom nurses while eating nothing herself. In tropical waters there’s nothing for her to eat. She’ll lose up to one third of her body weight before she can get back to temperate waters in the spring to feed.
Mama humpback is fiercely protective of her baby, which is vulnerable to attack by transient ( mammal-eating) killer whales during migration and at the feeding grounds. Turns out humpback males aren’t the only talkers. A recent study revealed that mothers and calves quietly “whisper” to each other, probably to stay under the radar of killer whales!
A transient killer whale and humpback interaction, 2016. / Photo by Valerie Shore, Eagle Wing Tours
- They’re interfering busybodies.
Speaking of killer whales, humpbacks don’t like them much. Not at all, actually. You’d think, though, that if killer whales were trying to kill and eat something else nearby you’d hightail it out of there. Last thing you want to do is get involved and risk becoming dinner yourself.
Wrong. Turns out it’s the first thing a humpback might do. About 10 years ago a whale researcher visiting the Antarctic watched in astonishment as a pair of humpbacks inserted themselves into a killer whale attack on a Weddell seal. One of the humpbacks rolled over to let the seal take refuge on its belly, even nudging it back into place with a flipper when it began to slip off.
A subsequent literature review showed that these acts of humpback “do-gooding” are widespread. Doesn’t matter what’s being attacked—humpback calves, calves of other whale species, seals, sea lions, dolphins, porpoises, you name it. Humpbacks interfere. They’re the self-appointed bouncers of the whale world. We’ve seen it here in the Salish Sea several times now.
What’s going on? Is it altruism? Compassion? Or an instinctive reaction to a predator? The scientific jury is still out. But what it does tell us is that we still have much to learn from these (mostly) gentle giants!