Humpback Whale

HOW TO SPOT

Watch for the tall columnar blows of humpback whales, which can be as high as 15 feet. Humpbacks have small, knobby-shared dorsal fins, and broad, lobed tail flukes with unique white patterns on the undersides. Humpback pectoral fins can be up to 8 feet long. With binoculars, it is also helpful to look for the tubercles on the head of the whale.

Humpback whales can also be identified by their surface activities, or aerial displays. They are the most acrobatic large whale. Humpbacks will breach (jump out of the water), slap their pectoral fins, tail flukes, or caudal peduncles on the surface of the water. These behaviors are known as tail lobbing, flipper slapping, and peduncle throws.

WHEN AND WHERE TO SEE

Humpback whales are making a comeback in the North Pacific and might be seen from any Whale Trail location on the Pacific Coast. The best time to spot them is spring and summer, as they migrate north from winter calving and breeding grounds to summer feeding grounds.

Humpbacks gather in great numbers each summer in Monterey Bay, attracted by schools of baitfish. Farther north, a group of at least 15 humpbacks return to feeding grounds in Johnstone Strait.

RANGE

Humpback whales live in all major oceans and travel great distances during their seasonal migration, the farthest migration of any mammal. In the summer months, humpbacks are in high latitude feeding grounds and in the winter migrate to their calving grounds in subtropical or tropical waters.

In the North Pacific there are at least three separate populations.

• The California/Oregon/Washington population that migrates from Central America and Mexico to southern British Columbia in the summer.
• The Central North Pacific population that migrates between the Hawaiian Islands and northern British Columbia or Alaska.
• The third population is the Western North Pacific stock traveling between Japan and the Bering Sea/Aleutian Islands.

BIOLOGY

Humpback whales are the fifth largest whale and known as a “rorqual whale”. This family also includes blue whale, fin whale, Bryde’s whale, sei whale, and minke whale. Rorquals have long pleats from their lower jaw to the belly area, allowing the throat to expand while feeding and consume large amounts of water filled with food.

Humpback whale display sexual dimorphism, meaning females grow larger than males. Both male and female humpback whales have knobs on their heads, called tubercles. The knobs each have a sensory hair that is thought to detect water movement.

BIRTH FACTS

A humpback whale calf in between 10-16 feet (3-4.5 meters) in length and can weigh up to one ton (907kg). A calf will spend a year nursing on the mother’s rich milk, which is between 45-60% fat. The gestation period of a humpback whale is around 11 months and female humpback whales will give birth every 2-3 years. Males do not provide parental support for calves.

ADULT MALE FACTS

One of the most interested behaviors of humpback whales is done my males. Scientists have discovered that male humpback whales sing a long, complex song that can be heard for upwards to 20 miles (30km). The singing can last for hours, however, each song will typically last 10-20 minutes. All whales in a population will sing the same song, although the songs change, or evolve, year after year. The song of the North Pacific humpback whale is different than the song of the North Atlantic humpback whale. This singing behavior is thought to happen in the calving grounds, during the summer months, and has been studies for decades, although very little is understood about the function. Scientists believe male’s songs are likely to attract females or used in social structure and competition among males for a higher chance to mate.

SOCIAL STRUCTURE

The social structure of humpback whales is more simple than other whales. The mother-calf bond is thought to be one of the only social structures, with that bond only lasting around a year. Humpback whales are often solitary, however can be seen in groups up to 10-15 when feeding or in short-term social groups. In the mating grounds humpback whales can be seen in competition groups, however, it is thought that their 3,000 mile migration is done solo, with the exception of mothers and newborn calves.

BEHAVIOR

Humpback whales migrate from their warm winter breeding grounds to colder, more productive summer feeding grounds in higher latitudes. They feed mainly on krill, a small shrimp-like crustaceans, and other small school fish, such as herring and sand lance. Whales can eat around 1.5 tons (1,351 kg) of food a day. Humpback whales have several feeding techniques, with one being a cooperative feeding strategy called bubble netting. Several whales will create a circular wall of bubbles used to encircle their prey and then lunge through engulfing their prey.

STATUS

Of the fourteen district population segments for Humpback whales, two are endangered, two threatened, and ten are not at risk. The North Pacific humpback whale was down listed in 2011 in Canada (Species at Risk Act) and in 2016 in the United States (Endangered Species Act). Although estimating humpback whale abundance is difficult, it is thought the North Pacific humpback whale is increasing in abundance at around 4.9-6.8% annually. It is believed the number is between 18,000-30,000, which is about 30-35% of their historic population size. Humpback whales were fairly common in Northwest inland waters pre-1900, however their entire summering population was likely decimated during one whaling season out of Nanaimo, B.C.’s Page’s Lagoon in 1907-08.

CURRENT AND HISTORICAL THREATS

The main threats humpback whales face is entanglements in fishing gear and bycatch. Other threats include vessel collision, known as ship strike, whale watch boat harassment, and habitat impacts.

RESOURCES