Humpback Whale

Humpbacks are well known too for their haunting and beautiful vocalizations that are generally heard in their winter courtship grounds. Its long pectoral fins inspired its scientific name, Megaptera novaeangliae, referring to New England, the location where European whalers first encountered them. Humpback whales are a favorite of whale watchers as they are often active, jumping out of the water and slapping the surface with their pectoral fins or tails.

Featuring one of the longest migrations of any animal on earth, humpbacks fast during the winter and gorge themselves in the summer when they travel toward the north and south poles to feed in the nutrient-rich waters.

Join us as we explore the captivating world of humpback whales, uncovering their ecological significance, and the threats they face in a changing world.

Appearance

Humpback whales are some of the largest animals on the planet. And while they’re still dwarfed by blue and fin whales, an adult humpback whale can be up to fifty feet long and can weigh up to about 40 tons.

They have a robust body shape, with a distinctive hump on their back and long, knobby flippers, the longest of any whale species. Their heads are broad and covered in bumps called tubercles, each containing a hair follicle. When they breach, their massive size and weight are apparent, and the distinctive shape of their hump and long flippers make them unmistakable.

Individuals have different amounts of white on their pectoral fins, bellies, and the undersides of their flukes (tails). Their flukes can be up to 18 feet wide—they are serrated along the trailing edge and pointed at the tips. Southern Hemisphere humpback whales tend to have more white markings, particularly on their flanks and bellies than do Northern Hemisphere humpback whales.

At the surface, humpbacks appear dark grey and are easy to spot thanks to their fifteen-foot spout when they exhale. Humpbacks have two nostrils, like we do, located on the top of their head.

A humpback’s pectoral flippers are the longest of the great whales and can be up to a third of the whale’s body length. These give humpbacks superb maneuverability despite their huge size, allowing them to search for food close to shore and in shallow waters.

Typical humpback surfacing behavior is 5-8 breaths over several minutes in 30-second intervals followed by a dive of 5-10 minutes, although they can stay down for over half an hour. Before doing a big dive, a humpback will arch or “hump” its back before flipping its tail high above the surface.

Habitat

Humpback whales can be found in all four oceans, depending on the time of year. They show seasonal migration, with a few populations logging some of the longest migration distances of any marine mammal.

There are three distinct populations of this migratory species in the North Pacific: a North Pacific stock that winters in Central America and migrates to the California coast and British Columbia in the summer; a Central North Pacific stock that winters in Hawai‘i and migrates to Canada and Alaska in the summer; and a Western North Pacific stock that winters near Japan and likely migrates to the Bering Sea in the summer.

In general, humpback whales spend the warm summer months in temperate or polar latitudes where their food is more plentiful due to the extended sunlight and higher temperatures. After feeding nearly 24 hours a day for 6-8 months, humpbacks migrate back to the equator for the winter, a journey that can take up to six weeks in some cases.

In these tropical waters, humpbacks enjoy something of a vacation. They’re more surface active with increased levels of breaching, tail lobbing, and pectoral fin slapping. They give birth to their calves in this warmer water, and mating is also believed to occur here.

Humpbacks are usually solitary animals and don’t have consistent pods as many toothed whales do. They can be social, however, especially in their winter breeding grounds.

Diet

Humpback whales are also called “baleen” whales. Instead of teeth, they have fibrous hairs made of keratin that hang down from the upper jaw of their mouths called baleen plates. Instead of chewing their food, they filter feed, taking large gulps of water and straining it through the baleen, trapping their food like a giant colander.

Humpback whales often bear rake-like scars on their bodies indicating that they survived an attack by killer whales.

Some humpbacks have been observed creating “bubble nets” to catch their prey. The whales dive deep and then swim up in a spiral pattern while releasing a steady stream of bubbles from their blow holes. As the bubbles rise they form a “net” that surrounds the whales’ prey. The whales swim up through the centre of the bubble net and feed on the prey trapped inside.

Despite their size, the throat of a humpback whale is tiny, roughly the width of a large grapefruit. This limits their potential prey to small fish and krill.

The specific species they prey upon varies from place to place. For example, the humpback whales of the North Pacific feed largely on forage fish that travel in huge schools. These include species like herring, sand lance, anchovies, and capelin.

Zooplankton and tiny shrimp are other common food sources throughout a humpback’s habitat. Commonly referred to as krill, these tiny organisms make up the foundation of the ocean food chain. These huge blooms of plankton and krill can represent a huge ratio of the ocean’s organic biomass, ensuring that there is enough food to sustain these massive baleen whales throughout the northern and southern hemispheres.

Reproduction

Humpback whales breed on the Pacific coast of Mexico and give birth in tropical waters. When born, baby humpbacks are 10-15 feet in length, but they grow quickly, averaging about one-and-a-half feet per month. Infants subsist on their mother’s rich milk for most of their first year of life.

Humpback calves spend the first year of their life with their mother, making one round-trip migration together before setting off on their own.

There’s a lot of variability in how often humpbacks reproduce. Females reach sexual maturity between the ages of 6 and 10. Some females have more than ten calves in their lifetime, while others have just one or two. Others have never been observed with a calf of their own but act as “surrogates” or “escorts,” assisting other females with their offspring.

Gestation is estimated at approximately 11 months, so mating must also occur in tropical waters. However, the mating behaviors of humpbacks are still poorly understood. During the winter, males will often form into competitive groups vying for the attention of a female. This can sometimes turn violent, with several males jostling for position, although fatalities are rare.

The actual act of mating has not been documented. It’s theorized that couples must dive deep beneath the surface, but it may also occur offshore on the way from the summer feeding grounds.

Threats

Until the mid-20th century, humpbacks were subjected to commercial whaling throughout most of their range, with many populations dropping to less than 10% of their historical numbers.

A whaling mortarium and the inception of organizations such as Greenpeace and the International Whaling Commission have allowed many humpback whale populations to rebound. The North Pacific stock was removed from the endangered species list in 2016.

Today, humpbacks are only hunted in parts of Greenland by subsistence hunters who take only one or two individuals a year.

Other threats such as climate change, decreasing prey populations, overfishing, entanglement in fishing gear, increased boat traffic, and risk of ship strikes are some of the biggest issues concerning humpbacks.

The IUCN red list has categorized it as a Least concern. As one of the more charismatic of the whale species, these mammals are a popular attraction for the whale-watching industry. While this allows whale lovers to enjoy and appreciate wild whales, the increasing number of vessels and anthropogenic noise may be having harmful effects that are not understood now.

More Interesting Facts about Humpback Whale

1. Each humpback whale tail is unique. Much like our fingerprints, scientists can compare photos to track the migration and feeding patterns of individual whales.
2. Humpbacks have proven to be accomplished hunters capable of feeding in a wide variety of conditions.
3. Its milk is pink in color and 50% fat, roughly the consistency of yogurt.
4. They breach for a variety of reasons, such as communication, sloughing off dead skin or parasites, a behavior change, and exercising their calves in preparation for their long migration.
5. Humpbacks are highly inquisitive and will approach quite closely, showing little fear of boats.