Facts about whales, dolphins, and porpoises
What is a whale?
Whales are warm-blooded mammals that live in the sea, breathe air, and nurse their young with mother’s milk. They are often called marine mammals
Dolphins and porpoises are small whales. There are around 80 different kinds or species of whales and dolphins. Whales can be divided into two groups: those with teeth, called toothed whales, and those without called baleen whales.
How did whales evolve (develop)?
About 50 million years ago, the ancestors of whales were small, furry creatures that lived on land. Slowly over millions of years, these creatures changed, or evolved, into animals that spent more and more time in water. Their front legs became flippers and a thick layer of fat called blubber replaced their fur coats to keep out the cold. Eventually, they lost their back legs, as their tail became bigger and stronger for powerful swimming. Gradually their nostrils moved to the top of their heads so that they could breathe and swim at the same time.
How do whales breathe?
Whales must come to the surface to breathe. When they breathe out, the warm air sometimes forms a cloud called the whales ‘spout’ or ‘blow’. Just like when you breathe out on a cold day. This is how people can spot whales from far away at sea.
What and how do whales eat?
Baleen (non-toothed) whales, such as the blue and humpback whales, are very big and have large plates that hang down from their upper jaws instead of teeth. Baleen is the name of these plates and it is made of a tough material, called keratin like your fingernails. Baleen plates sieve or strain food from the water.
The whales swim along and take a huge mouthful of water full of tiny shrimps called krill. Closing their mouths, the whales push the water out with their tongues, through the baleen plates, trapping the shrimps inside. They then swallow up to a ton of krill in one great big gulp.
The toothed whale group have teeth instead of baleen. They eat a wide range of food including fish and squid.
Some whales are the largest living creatures ever to exist. They can grow bigger than the biggest dinosaur. An elephant could sit on a blue whales tongue. Its heart is the size of a small car! A blue whale can be over 30 metres long and weighs over 150 tons. A baby blue whale is 7 metres long at birth, weighs around 3 tons, drinks 400 litres of its mother’s milk every day, and gains weight at 4.5 kilos per hour!
The largest toothed whale is the sperm whale, which can grow up to 20 metres long. Sperm whales have the largest brain ever evolved. They eat squid that they catch way down in the ocean depths. Sperm whales can dive up to a mile below the ocean surface and can hold their breath for up to an hour! You may have read the famous book about a white sperm whale called ‘Moby Dick’. Most toothed whales though are very much smaller than sperm whales; these are the dolphins and porpoises.
How do whales communicate?
Whales have large complex brains and scientists think they are very intelligent. Whales produce many sounds and can talk over great distances to one another. Male humpback whales ‘sing’ when they are courting females. People have recorded humpback whale songs. They were even sent into space aboard the ‘Voyager’ spacecraft. Whale songs have been best-selling hit records!