Brownies support whales and dolphins

Fascinating Facts About Whales And Dolphins

Here are the answers to some of the questions we get asked most frequently about whales and dolphins. If you have another, please do email us at and well do our best to answer.

What do whales and dolphins eat?
This really depends on the species of whale/dolphin and where they live. For example, the bottlenose dolphins living in the Moray Firth, Scotland have different favourite fish depending what time of year it is. In the spring and summer there are big, juicy salmon available for them but in the winter months there are herring and mackerel. So its a bit like a restaurant having a different menu. Bottlenose dolphins living elsewhere may feed on more tropical species of fish or tuck into an octopus or squid.

Some orcas (killer whales) eat only fish – a favourite being salmon – and others eat much bigger prey including seabirds and mammals such as sea lions. It depends on what food is available to them where they live and what techniques they have learnt to hunt their food.

Most of the biggest whales (including blue whales, fin whales and humpback whales) don’t have any teeth but have baleen instead which hangs from their upper jaw and acts like a sieve. They tend to eat smaller prey, despite their own enormous size. These whales gulp in tonnes of water and food (such as fish or krill) and then push the water out through the baleen, trapping the food inside their mouths.

How big/small are whales and dolphins?
Blue whales can reach 33 metres in length and are the largest animals ever to have lived on Earth (larger than any known dinosaur)! Their arteries are as big as drain pipes and their mouths so huge that an entire football team could stand on one of their tongues! At the other end of the scale are the tiny Hector’s dolphins and finless porpoises. They are only about 1.4 metres long and are very light, 3000 finless porpoises would weigh about the same as just one blue whale!

How do dolphins sleep?
Unlike you and me, dolphins have to be conscious to decide when to breathe. If they went into a deep sleep they would stop breathing and suffocate or drown. So, their solution is to let only one half of their brain sleep at a time. This way they get the rest they need but stay semi-conscious to continue breathing and look out for any dangers.

How do dolphins drink?

Dolphins don’t need to drink like we do. Their main prey (fish and squid) contains large amounts of water and so dolphins gain water from their food. In addition, dolphins don’t actually need to take in very much fluid because, unlike us, they don’t lose water by sweating.

How long do whales and dolphins live?
In the wild cetaceans live for a long time - generally the larger species living the longest. Bowhead whales spend their lives in cold Arctic waters. They may be the world’s oldest mammals and are the longest lived of all whales – possibly over 200 years! The harbour porpoise is probably the shortest living cetacean, with most individuals dying before they are 12 years old. Cetaceans that are kept in captivity die much earlier than those living in the wild.

What sounds do dolphins use to communicate?
They use many sounds including clicks, whistles and squeaks.

What is echolocation?

It is the use of sonar to find out where objects are. Dolphins send out sounds and listen to the echo, this tells them exactly what is around them and where their prey is.