Humpback Whales | Orca | Fin Whales | Whales & Sound | Identification of Whales
Humpback Whales
The return of humpback whales to our research area has been dramatic. In 2004, 42 individual humpback whales were identified in the Caamano Sound to Douglas Channel region. By the end of our 2019 season this number was 426 individual identified and many of these return year after year and are referred to as seasonal resident humpback whales. We now sight humpbacks on a daily basis during the field season. Thanks to this high abundance we have been able to gain great insight into the social behaviour and habitat use of this robust cetacean.
Historically, humpback whales were commercially hunted from the late 1800s to 1965. During this time period an estimated 28,000 humpback whales were caught in the North Pacific. The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) proposed that the population be listed as “Threatened”, based on low observed densities of humpback whales in British Columbia. This threatened status has recently been re-assessed by COSEWIC and humpbacks have been down-listed to a species of “Special Concern” due to the increase in the population. This re-assessment is being challenged by a number of researchers.
The social relationships humpbacks have developed with each other are through direct experience and by choice, and not necessarily due to family bonds. Humpbacks have displayed many aspects of their unique behaviour in our research area. Many of which are essential skills that mothers teach their calves, enabling them to survive independently into the following season.
Many people have shared with us their personal encounters with these gentle giants. Though each story is different, the theme remains the same, a moment in time where you feel completely connected and aware of the intelligence of these whales. This website is an effort to demonstrate the absolute wonder of humpback whales and an opportunity for you, the public, to play a role in the identification and protection of these magnificent creatures. Hopefully, the expansion of public awareness will create an overall global passion and understanding for humpback whales, thus to marvel at the astounding beauty of their size and the complexity of their mysterious song that has evolved over many centuries.
HUMPBACK MIGRATION
The humpback whale is a migratory species feeding from spring through fall in high-latitude nutrient rich waters. In early winter they migrate to sub-tropical and tropical waters for calving and breeding. They do not feed during this winter migration. Every fall we know that one by one they will slowly begin their annual migration south.
The first to leave are mother and calves, then sub-adults then adult males. The last whales to leave the feeding grounds are the pregnant females. They will need every ounce of nutrition to sustain them during the rigors of the long migration, birthing and then nursing their calves. There is no food available for these mothers in the calving grounds and they will not forage their next meal until travelling northwards again, this with a calf by their side.
Some of our resident humpback whales migrate to a group of islands east of Japan. Another group makes the long voyage to Baja and Hawaii. The migration will take from 4 to 8 weeks. The estimated distance each way is 3000 miles, which is one of the longest known migrations of any mammal.
It is only through identification work and number of sightings per individual per month we can determine the length of time a whale stays in the area. Humpback whales have been sighted year round in northern BC, but this could be due to the timing of whales migrating at different times. Some humpbacks can leave as late as February to travel south, which could overlap with the arrival of others that are already returning from their calving and breeding grounds to the south. There are still questions we need to understand and cooperation between researchers to truly understand if there has been a change in the migration culture of humpback whales
BUBBLE NET FEEDING
Clearly, the humpback whales are returning for a reason and it is evident that the geographic region from Caamano Sound to Douglas Channel is a vital feeding ground. In early spring, after the 3000-mile migration from the tropics, humpback whales have lost a large portion of their body weight. There is no food available in the warmer waters of Mexico and Hawaii so when they arrive up north they are in dire need of food. The feeding frenzy begins immediately and will last from dawn to dusk.
We are very fortunate in our research area as the most common form of foraging is bubble net feeding. During this feeding display they will cooperate in groups from 2 to 15 individuals. The technique they use to ensure each whale has the opportunity to feed is inspirational and spectacular to witness. Once every whale has taken a dive the true work begins, hundreds of feet below the surface. The whales will dive below a school of prey, and then slowly they begin a spiral dance upwards towards the surface, blowing bubbles in a circular motion forming a net. On the surface you will actually see a circle of bubbles form as the whales move in this spiral formation. The purpose of the bubbles is to congregate the school of herring and force them towards the surface near the centre of this circle.Then the feeding calls begin, long hollow calls, followed by higher pitched squeals.
The whales use these specific calls when they are feeding and the calls play a huge role in this feeding technique as they further congregate the fish. What we witness next at the surface is an explosion of air as these whales surface in the centre of this bubble circle, their mouths gaping wide open, full of small fish jumping for their lives.
Humpback whales have 14 to 35 throat groves that run from chin to navel. These grooves facilitate the expansion of the throat. This expansion allows for large volumes of water and food into the mouth. As the mouth closes the whale will press down with its tongue forcing all water out through baleen plates. These baleen plates hang in rows from each side of the upper jaw and act as a filter, keeping all the small fish from escaping. Baleen is made of a protein, referred to as keratin, which is both strong and flexible. With this innovative evolutionary adaptation the humpbacks feed on krill, and various species of small shoaling fish such as herring, pilchards and mackerel.
On the sidelines are a variety of humpback companions, such as seals, sea lions, Dall’s porpoise and an assortment of sea birds taking fish from the whales have been injured or left behind. We imagine, just like us, all these species are waiting for the arrival of this food frenzy so they may participate in one of the planet's most outstanding display of cooperative feeding.
Humpback Song
In early fall we will witness a change from cooperative feeding to more robust types of behaviour such as breaching and tail or pectoral slaps. Males will form posturing groups and compete to escort a female to the breeding grounds. During these competitions males may become quite aggressive towards each other. On many occasions we have seen a group all dive together, then moments later appear back at the surface, tonal blows echoing through the channels, fresh bloody scratches along their bodies as they battle each other under water. It is also during this time of that the males will begin to sing their beautiful songs for all hours of the night.
For more than 40 years, researchers have been following a complex underwater song that is constantly shifting and reshaping as each season passes. This song, which can range anywhere from 10-30 minutes long, is performed solely by male humpback whales -- but for a reason that currently eludes scientists. During the song, humpbacks produce an intricate series of sounds ranging from high frequency squeals to deep, low frequency rumbles. The structure is rigid and predictable, and researchers have deconstructed its components into hierarchal elements. The base units (or notes) are singular units of sound, which are linked together to form what is referred to as a sub-phrase. Sub-phrases contain 4-6 notes, and a pair of these groupings is called a phrase. Humpbacks tend to repeat phrases perfectly over and over for up to 4 minutes, and the repetition of a select phrases leads to a theme. The male humpback song is then composed of a collection of various themes, repeated in specific order, delivered with similar musical devices, which are similar to that of a human song, for example, where the emphasis is on the variation in tempo, and the crescendo. As far as we know, humpback whales are the only animals, other than humans to create such complex, hierarchal patterns of sound.
What makes the song even more fascinating is its evolution between seasons. In any given area, in any given period of time, all singers will perform nearly identical versions of the song. It is most commonly sung during the mating season, but undergoes surprising transformations between years. Sometimes the song will only change subtlety, which is revealed by a slight variation in tone or volume. In consecutive other years, the song is almost unrecognisable. Sections may completely disappear, and new themes become incorporated. Regardless of the scale of change, however, all singers within the same geographical region will adopt the same adjustments.
Although researchers have managed to understand and monitor the basic song structure, there are many aspects of the song that continue to puzzle scientists. It is unclear why the same song evolves each year, or who initiates the changes. Why are some changes accepted while others ignored? And most importantly, what purpose does the song serve? Since it is sung primarily during the mating season it is presumed to be related to sexual selection. There are theories that suggest these performances strengthen bonds between male humpbacks and convey information about the individual singer. But for now, the song is a mystery that scientists are trying to unravel, note by note.