Humpback Whale

Famous for their incredible aerial leaps, pectoral slaps, and tail lobs, humpback whales are one of the most popular and watchable whales. Humpbacks are well known too for their haunting and beautiful vocalizations that are generally heard in their winter mating grounds. While the purpose of these calls is not fully understood, we do know that only the males “sing” and that the “song” is intricate and complex, changing every year.

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.

Humpback 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 almost one ton per foot.

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. When they breathe, the plume billows into a telltale heart shape, making them simple to identify, even at a distance.

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 the course of 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.

Humpback Diet

Humpback whales are mysticetes or “baleen” whales. Instead of teeth, they have fibrous hairs made of keratin that hang down from the upper jaw of their mouths. 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.

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.

Humpback Habitat and Habits

Humpback whales can be found in all four oceans, although when you can find them, there depends on the time of year. Humpbacks are migratory animals, with a few populations logging some of the longest migration distances of any marine mammal.

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.

During the summer, humpbacks will, at times, come together in groups of up to twenty animals to feed cooperatively. Bubble net feeding, one of the most famous feeding behaviors, is commonly seen in southeast Alaska. Several whales will work together to surround a school of forage fish. Another individual then blows a ring of bubbles to trap the school. Once ensnared, the whales’ rocket through the school with mouths open toward the surface.

Humpback Reproduction

Humpback whales 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 become reproductively active 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. But 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 to Humpbacks

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 that take only one or two individuals a year.

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

As one of the more charismatic of the whale species, humpbacks 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 deleterious effects that are not understood at this time.

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. The ability to manipulate their environment and utilize tools such as bubbles for bubble-net feeding are indicators of their intelligence.
3. Humpback milk is pink and color and 50% fat, roughly the consistency of yogurt.
4. Humpbacks 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. The rostrum or nose of a humpback is covered in small bumps. Known as tubercles, these bumps have individual hairs that work like whiskers, allowing humpbacks to sense changes in the water current and locate their prey at close range.