Whales make up some of the largest animals on earth. In fact, the largest animal that has ever lived is believed to be the blue whale.

Whales are actually mammals, and like humans, they have lungs. They breathe through a blow hole, drawing air into their lungs, so even while they may spend all their time in the water, they must come up to the surface in order to breathe.

Antarctica is home to a number of whales.

Blue whale

These huge animals can grow up to 30 metres long, but what might surprise you is they get to this size on a diet of krill. They take huge mouthfuls of water and krill and, instead of teeth, they have what are called ‘baleen plates’, which act like a sieve, allowing the whale to push the water out of its mouth while keeping the tasty krill inside.

Blue whales tend to travel by themselves or in pairs, but they are able to stay in contact with other whales through loud calls that can be heard around 150 kilometres away. This sound gives the blue whale the honour of not only being the biggest animal in the world, but it is thought also the loudest!

Orca or killer whale

Orcas are the black and white whales that we often see on TV and that are found all over the world. In many ways, they deserve their name of killer whales because they hunt in packs called pods (usually made up of family members) and they are efficient predators that share their kill among the group. Their diet is varied – they eat fish, squid, sharks, seals, penguins and even other whales.

Orcas use a special technique called ‘echo location’ to find objects and navigate the world. They send out sounds (that sound like clicks and squeaks to us) that bounce back off objects, and the orcas use this information to determine how far away something is or how big it is. In this way, they can swim in the dark and not worry about getting lost!

Humpback whale

Humpbacks are highly vocal and highly social animals. Like the orca, they travel in large groups – for humpbacks, sometimes these pods number up to 200 individuals. The male humpback sings complex songs, sometimes singing for hours at a time. But it’s not always the same song – slowly, over time, the song changes so that, in a few years, it is a completely different song. And despite scientists being interested in how this singing is done, no one is yet sure. Humpbacks have no vocal cords, no air escapes during the singing sessions and their mouths don’t move.

    Published 4 September 2008