The largest animal – the blue whale – sets a number of impressive records. It’s also one of the loudest and hungriest species on Earth.

Did you know the Antarctic blue whale is the largest known animal to have ever lived on Earth? It’s difficult to grasp just how big these gentle giants are - imagine an animal the length of three school buses and as heavy as 33 elephants. That’s the scale of the blue whale!

These enormous marine mammals can grow up to 30m in length and eat up to 3,600kg of krill a day. As blue whales are baleen whales, they have hundreds of baleen bristles lining their mouths instead of teeth. They use these bristles to trap prey and filter out water in massive quantities.

Living an average of 80 to 90 years, blue whales migrate every year in search of food and breeding grounds. They spend summers gorging on krill in the Antarctic’s cold polar seas before heading north to warm tropical waters to breed and escape the harsh winter. If you’re lucky, you might be able to spot a blue whale off Australia’s southern coasts in spring and autumn during their annual migration.

Blue whales may be the rulers of the ocean, but sadly, they’re classified as Endangered by the IUCN Red List. Fortunately, WWF-Australia is working to protect all whales and their precious ocean home, and you can help make a difference.

Blue whale (Balaenoptera musculus) in Mirissa, Sri Lanka
Blue whale (Balaenoptera musculus) in Mirissa, Sri Lanka © Shutterstock / Ajit S N / WWF

Species bio

Common Name

Blue whale

Scientific Name

Balaenoptera musculus


  • Balaenoptera musculus musculus - Northern blue whale
  • Balaenoptera musculus intermedia - Antarctic blue whale
  • Balaenoptera musculus indica - Northern Indian Ocean blue whale
  • Balaenoptera musculus brevicauda - Pygmy blue whale
  • Balaenoptera musculus unnamed subspecies - Chilean blue whale.


Length: 24-33m Weight: Up to 200 tonnes Population: 10,000-25,000


Listed as Endangered (IUCN Red List)

What we're doing to help blue whales

Tail fluke of a blue whale diving. Marissa, Sri Lanka
© Richard Barrett / WWF-UK

Securing critical ocean habitat for whales

Blue whales face a growing number of threats from human interference. Ship strikes, chemical and noise pollution, bycatch and climate change all pose a significant threat, and sadly, blue whales are Endangered as a result. We need to take action now to remove these threats and protect whales. WWF-Australia is working with our neighbours in the Asia-Pacific region to support efforts to protect 30% of our shared oceans by 2030, and we’re working to unite key southern hemisphere countries to protect 100 million hectares of ocean.


Protecting ‘whale superhighways’

Whales migrate around the world every year following specific routes known as ‘whale superhighways’ or ‘blue corridors’. WWF-Australia is working with partners to map these migratory routes and potential threats. Our goal is to connect networks of Marine Protected Areas (MPAs) to ensure safe passage for blue whales and all marine animals.

Read more
Blue whale near surface in Mirissa, Sri Lanka.
Blue whale near surface in Mirissa, Sri Lanka. © Shutterstock / Ajit S N / WWF

Securing a healthy climate for – and with – whales.

Australia can become a global leader in securing a healthy and resilient net-zero world. WWF-Australia supports the transition to renewable energy and nature-based solutions and integrating the vital ecological role of whales into environmental policies.

Why it matters

Whales play a vital role in their marine ecosystem and in combating climate change. Their impact shines in two fundamental ways: fertilising the ocean and absorbing carbon.

Blue whales require enormous amounts of food, and their iron-rich faeces (poo) is an essential source of nutrients in the marine food chain. These nutrients, particularly iron and nitrogen, are vital for phytoplankton. Phytoplankton generate over half of Earth’s oxygen and absorb around 40% of all carbon dioxide produced. By fertilising their growth, whales contribute significantly to keeping our planet healthy. 

Additionally, when whales die and descend to the seabed, so does the carbon stored in their bodies. Over their lifetime, these gentle giants capture a staggering amount of carbon - equivalent to thousands of trees. Their impact is pivotal to ensuring balance both in the ocean and outside of it.

Blue whale breaching in the sea, Baja California, Mexico
Blue whale breaching in the sea, Baja California, Mexico © Shutterstock / Westend61 on Offset / WWF

Whale wonders: did you know blue whales are the loudest animals on Earth?

Blue whales hold the record for being the loudest in the animal kingdom. With a heart the size of a small car, their heartbeat can be heard from three kilometres away. But that’s nothing compared to their call. A blue whale’s low-frequency whistle is as loud as a jet engine, reaching up to 180 decibels. The sound travels across hundreds of kilometres and is an essential tool for scouring the vast ocean in search of food and mates. Discover more interesting whale facts below.

Read more whale facts here


Despite their vital role in the ocean and keeping carbon out of the atmosphere, blue whales have faced threats from humans for centuries. Commercial whaling pushed their population to the brink, and it wasn’t until 1966 that the International Whaling Commission banned commercial whaling practices on blue whales.

Before whaling, there may have been as many as 250,000 blue whales, but today, it is one of the world's rarest species, with a population of just 10,000-25,000. Sadly, blue whales face a multitude of threats from human interference. However, it’s not too late to change their fate.

Climate change

Climate change is impacting water levels and temperatures around the world. As a result, krill populations are reducing, making it harder and harder for blue whales to find food. Antarctica, for example, was once a haven abundant in rich food sources for blue whales. Rising temperatures and melting sea-ice have decreased krill populations, resulting in less food for whales.

Growing ship traffic

Ship traffic poses a huge threat to whales. For millions of years, blue whales have cruised the world's oceans with few threats, their sheer size leaving them largely free from danger. However, ever-expanding ship traffic is leading to increased collisions between boats and whales, often resulting in fatal outcomes for the whales. Keeping ships out of ‘whale superhighways’ is essential to protecting whales for years to come.


What you can do to help

  • Increase your impact and donate to help keep whales safe on their long ocean journeys.
  • Learn more about whales and why we need to protect them.
  • Responsible whale-watching. Whale-watching is one of the fastest growing nature-based tourism activities in the world. Choose a responsible whale-watching company that abides by local and national laws.