• Mel

Animal Spotlight: Humpback whales

Updated: Jun 4

We thought it would be nice to have an Animal Spotlight every few blogs to share knowledge on our favourite marine life! This blog is focused on humpback whales - hope you learn as much as I did during my research!

A humpback whale breaching

It’s always such a wonderful thing to see a whale breaching out of water whilst on a walk at the beach. Chances are, if you’re in Sydney in Summer, it’s a humpback whale that’s putting on a show for all the beachgoers! You can tell if it’s a humpback by their distinctive black/dark blue and white colouring, and the grooves on their neck and throat. Humpback whales also have a small lump in front of their dorsal fins - which is where the term ‘humpback’ comes from.

Humpback whales are particularly acrobatic, making them favourites of whale watchers. They frequently jump belly first out of the water, slapping their flippers and fins to make large splashes. Sometimes, they’ll jump nose-first out of the water, calling sky-hopping, as well as twist their lower body above water and slapping their tail down, called a peduncle throw.

A pod of humpback whales skyhopping

It’s interesting that variations of these flashy moves can also be used as feeding techniques! Humpback whales annually migrate from colder Antarctic feeding waters in Winter to the warmer tropical breeding waters closer to the equator in Summer - it’s in these warmer seasons that they swim so close to shore, perfect for whale watching. However during Winter, humpback whales will focus their energy on eating.

Humpback whales are filter feeders, which means they’ll lunge with an open mouth, scooping up both water and prey, then filter the water out to swallow the leftover food. They usually eat small crustaceans like krill, shrimp, plankton and small schooling fish. Humpback whales often work as a team to feed, using their flippers, sounds, or a technique called ‘bubble netting’. This is where bubbles are exhaled below the school of prey, trapping the food inside a wall of bubbles. The whales will then lunge up in the middle to take a mouthful of food! This technique is used slightly differently between humpback whales living in different regions of the world!

Another behaviour special to humpback whales (and some other baleen whales) are their beautiful songs, which are a complex mixture of moans, cries, and other noises. We’re not entirely sure what the purpose of these songs are but scientists predict they’re used to communicate and attract mates! During their annual migration, male humpback whales have been observed singing - possibly for territorial or mating reasons. Mother whales and their calves are also known for communicating with each other through sounds!

A humpback whale and her calf

Despite their beauty, there were times when humans hunted whales for our own selfish gain. During the 1960s to 1970s, when the whaling industry was at its peak, the humpback whale population was reduced drastically. After the Commercial Whaling Moratorium (1985) was enacted, population numbers have gradually stabilised. At the start of 2022, humpback whales were removed from the threatened species list, with their conservation status now at Least Concern. This means that numbers are starting to increase in trend, however, many conservationists warn this delisting could be too early as humpback whales are still at risk from many unmanaged threats.

A report released by the IPCC in 2013 stated that the ocean has absorbed 93% of excess heat produced by greenhouse gases. As a result, the ocean becomes warmer, and aquatic ecosystems and their marine life are negatively affected. The population of prey species, like krill and plankton, is diminishing due to ocean warming, leading to less food available for humpback whales and the rest of the food chain. Habitats are also being destroyed; for example, coral bleaching is occurring in reefs all around the world - and in our own Great Barrier Reef! We know that this has dire consequences as 25% of marine species depend on coral reefs! As humpback whales rely on the seasonal temperature of the oceans for migration between feeding and breeding waters, ocean warming also affects the timing and distance of their migration, and can even limit their ability to reproduce and navigate.

Additionally, with so much human activity in the ocean since Industrialisation, including fishing boats, tourism, and gas development, there has been an increase in unnatural underwater noise. Scientists have seen this noise pollution disrupting normal marine life behaviour. For humpback whales, noise pollution can interrupt their communication, cause increased stress, and impede on feeding.

A fishing boat watching a humpback whale breach

Other threats to humpback whales include plastic pollution and ship collisions. Humpback whales can become entangled in fishing gear or other plastics in the ocean, and will be unable to break free, often having to swim long distances with the plastic wrapped around its body. This results in abnormal fatigue, limits their ability to feed and reproduce, and often leads to injuries that may cause death. Humpback whales are also at risk of colliding with ships, especially as they swim closer to human settlements during Summer. These strikes can cause severe gashes, with some severe injuries killing the whales.

Whaling also continues to be prevalent in countries such as Japan, Iceland, and Norway. Despite the Commercial Whaling Moratorium, these countries claim that the hunting is for ‘scientific purposes’. Yet, it is encouraging that humpback whales have recovered from their vulnerable status, serving as a reminder that other endangered species can similarly heal. We just need to remember that this recovery should only be the start of many improvements that will only occur with proper action against climate change, plastic pollution, illegal whaling, and exploitative fishing practices.

Phew! That was a lot of information!

Let us know what animal you want us to spotlight next!

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