ONE LIFE: Humpback whales

20 February 2022

Humpback whales are found in every ocean in the world. They have dark backs, light bellies, pleats on their throats, and a small hump in front of their dorsal fins, leading to the common name of "humpback”.

They can grow to 60 feet (18 metres) long, and can weigh 40 tons. Their flippers are the largest appendage in the world, growing up to 16 feet (5 meters) long, and their tails grow up to 18 feet (5.5 meters) wide. 

Humpbacks' heads are broad and rounded and covered with knobs, called tubercles. Each knob contains at least one stiff hair that is thought to act as motion detectors.

Humpbacks are globetrotters and migrate farther than any other mammal on Earth, travelling around 3,000 miles (5,000 kilometers) from summer feeding grounds near the poles to warmer winter breeding waters closer to the Equator. The exception is the humpbacks that live in the Arabian Sea. They stay there year-round.

Humpbacks typically travel alone or in small pods, consisting of two or three whales. When together, they communicate with each other and moms and their young touch fins as a possible sign of endearment.

Whisperings, whistles and songs 

Humpback whales are known for both their haunting and melodic songs and for breaching the water with amazing acrobatic abilities. 

Once in their breeding grounds, the males produce the most majestic and haunting of songs which can be heard up to 30 km away and are used to communicate with each other and potentially to attract mates. These songs are the most complex in the animal kingdom made up of sequences of high-pitched squeals and whistles, low rumbling-gurgles, moans, howls and cries.

The males may sing for many hours, repeating the song several times, and all males in a population sing a similar song, but the songs of each population are different. The song themes evolve gradually over time indicating the possible existence of song exchange and cultural transmission in the feeding grounds. A more recent hypothesis is that the whales are independently changing their songs in an acoustic manner that has not been previously recorded, with songs changing over time in a fashion that's even more precise than what humans do when language develops . 

But these gentle giants don't just bellow out loud songs. During their migrations, calves make very quiet ‘whispering’ vocalisations, much quieter than those of adult humpback whales, travelling some 100 metres instead of the several kilometres reached by the communicating males. These ‘whispers’ are thought to be used as a way for calves to communicate with mothers without being detected by nearby killer whales that use acoustic communications between calves and their mothers to locate them.

Empathic 

Humpback whales are one of the few known species to possess spindle cells in their brains. These are linked with feeling empathy and intuition about others’ feelings. This means that humpback whales can understand and feel for another whale in distress. In fact, the limbic system (which is responsible for processing emotions) in some whale species, is more complicated than it is in our human brains.  These spindle neurons are also associated with other advanced abilities, such as memory, reasoning, communication, problem-solving, and perception.

Altruistic

Humpback whales  engage in altruistic behavior during encounters with killer whales attacking other marine species, intentionally helping other creatures to escape certain death by orcas.

Humpback whales always protect their own calves, developing an anti-predation behavior known as “mobbing'' where adults will harass the predators to protect their offspring. However, humpback whales have also protected or rescued individuals from other species.

On May 3rd, 2012, in Monterey Bay, California, whale watchers witnessed a predation event involving nine transient killer whales and a mom/calf pair of grey whales. It is not rare for transient killer whales to go after mom/calf pairs. They usually try to separate them to go after the calf, drown it and then feast on its carcass. On this day, as whale watchers were observing the grey whale mom trying to protect her calf from the orcas, two humpback whales who were witnessing the event started harassing the killer whale pod. To do so, they got close to the grey whale pair, then splashed, and trumpeted at the orca pod. Their intervention lasted a while, but the orcas managed to drown the grey whale calf. Still, the two humpback whales, joined by three other pod members kept mobbing the killer whale pod by trumpeting, splashing, and tail slashing.

In 2009 a humpback was observed coming to the rescue of a seal after a pod of killer whales had knocked it off an ice floe back. A witness had also observed a group of humpback whales driving off a pod of killer whales that had killed a grey whale pup—they surrounded it and prevented the orcas from eating it for several hours. 

In total, over 115 incidents of humpback whales rescuing other creatures from orca attacks have been documented via published and unpublished papers, with just just 11 of the incidents involving rescuing humpback whale calves—the rest involving the rescue of a variety of other marine creatures such as sea lions, gray whales, sunfish and harbor seals.

The researchers found that many of the humpback whales that engaged in rescue attempts had scars on their bodies, indicating that they were survivors of orca attacks in their youth—it seemed plausible that they were simply responding to an unpleasant memory.

Humpback whales are the only cetaceans known to drive off killer whales under any circumstances, doing so to protect their young. The interventions could be accidental, as the whales have learned to respond to the sounds killer whales make when attacking, but they might do it simply because they see another creature under duress and wish to help.

Cooperative hunters

Humpback whales exhibit cooperative feeding, often with the use of a bubblenet. One or more whales will swim in a large spiral blowing bubbles (either throughout the spiral or only during portions of it) to encase and concentrate a school of fish or euphasids within a bubble-net. Individuals in a group will then coordinate their lunging through the centre of the bubble-net. The thought is that some fish may inadvertently escape from one mouth only to land in another’s, and larger schools of more mobile fish may be easier caught by a group of whales than an individual.

Excellent mothers

Mothers and their young swim close together, often touching one another with their flippers with what appear to be gestures of affection. Females nurse their calves for almost a year, though it takes far longer than that for a humpback whale to reach full adulthood. Calves do not stop growing until they are 10 years old.

Learn from each other

Humpback whales are known to learn from each other, with a community of whales off New England, USA, developing a new hunting technique by hitting the water with their tails while hunting to catch new prey  (sand lance) after the crash of the herring populations - there preferred prey- in the 1980s. This new technique subsequently spread to 40 percent of a humpback whale population by cultural transmission.

Humpbacks around the world herd shoals of prey by blowing bubbles underwater to produce 'bubble nets'. The feeding innovation, called 'lobtail feeding', involves hitting the water with the tail before diving to produce the bubble nets.

Whales dance

Humpback whales perform a slow dance together, swimming around each other in courtship. As one of the final stages of courtship before mating, the whales provide an amazing performance as they twist, twirl, roll, circle and dive around each other.

Whale fun

Humpback whales like to have fun, they breach out of the water and slap their pectoral fins and tails on the surface to create a splash

Whale grief

Humpback whales have the capacity to experience grief. 

Underwater cameraman Rodrigo Friscone Wyssmann observed a female humpback whale appearing to be inconsolable after her calf was attacked and killed by a group of orcas near Roca Partida in Mexico. The mother humpback sat motionless in the water column while her male escort swam nearby, trying to comfort her by touching her gently. The two whales remained near the site for nearly a week before finally moving on.

On Long Island, a nursing-age young humpback whale, ailing and alone but still alive, washed into the surf at Bridgehampton. A lighthouse keeper, 25 miles away at Montauk, described how she heard “incredibly mournful whale sounds”, the following day as if from a searching mother.

Whale help mitigate the impacts of global warming

Large whales are also highly migratory and carry nutrients via their waste from richly productive areas to poorly productive areas, thus cycling these nutrients where they are most needed to promote phytoplankton growth, which also sequesters carbon. As they rise up through the ocean to breathe and migrate across the globe, the iron and nitrogen in their waste provides ideal growing conditions for these microscopic creatures. In fact, most of earth’s atmospheric carbon (40% - 37 billion tonnes) is sequestered by oceanic phytoplankton, not terrestrial trees, although both do their part in sequestering carbon and providing it to living creatures as nutrients. A 1% increase in phytoplankton productivity is said to be equivalent to 2 billion mature trees

If we helped whales return to their pre-whaling numbers of 4- to 5 million (up from 1.3 million today), researchers say they could capture 1.7 billion tonnes of CO2 annually - with the cost of protecting them at just $13 per person a year.

Over a lifespan of around 60 years, whales - especially great whales, such as right and grey whales - accumulate an average of 33 tonnes of CO2. When they die, they sink to the bottom of the ocean, locking that carbon away for hundreds of years. By comparison, a tree absorbs up to 48 pounds of CO2 a year.

Humpback whales really are amazing animals.

Humpback whale conservation

Humpback’s are classified as ‘least concern; on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. However, as recently as 1988, humpback whales were listed as endangered. Populations have recovered, to between 30,000 and 40,000, which is about 30 to 35 percent of the population in 1940, according to the American Cetacean Society. The IUCN has a higher estimate of around 60,000 animals.

Commercial whaling of humpback whales is prohibited by the International Whaling Commission. Nevertheless, some humpbacks are still hunted, for subsistence purposes, in Greenland. Native people are allowed to kill a limited number of whales because whaling is classified as a major part of their culture.

Whale conservation

Whales are at the top of the food chain, and they have a crucial role in the overall health of the marine environment. Sadly though, they are at risk, and six of the 13 biggest whale species are endangered, despite decades of protection. 

Threats

The main threats to whales include collisions with ships, entanglement in fishing gear (discarded and in use), pollution, and commercial whaling. 

Shipping activity and oil and gas development all cause noise that disrupts and damages whale hearing. This causes them difficulty when feeding, migrating, and breeding. 

Whales are still hunted in some countries, despite there being a ban on international trade, and a moratorium on commercial whaling. Over 1000 whales are still killed each year for commercial purposes. 

Whales are also threatened by climate change. As the oceans warm and sea ice is lost, the habitats and food sources of some whales are badly affected. Whales, such as humpbacks and blue whales, may have to migrate further to reach feeding grounds as a result of climate change. These changes have already affected the reproductive rates of the endangered North Atlantic right whale, as they have less time to breed, as more time is spent foraging for food. 

Whale welfare

Whaling

Whaling is simply inhumane. It causes considerable, long-term and severe suffering to whales. Whaling methods have changed very little over the last 100 years, and this means that whales have suffered extensively for all this time

The whaler’s harpoon often fails to kill a whale instantly, so they are often shot, but not killed. They will instead experience massive injury and suffering as a harpoon is shot at them at great speed, and then detonated. If the harpoon doesn’t penetrate deeply enough, the whale will not die straight away, and may ‘escape’ to die slowly and painfully.


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