Whales, dolphins and porpoises all belong to a group of animals called cetaceans. This word comes from the Greek word ketos meaning a sea monster. These animals live in the sea and look like big fish. But they aren’t fish. They are all mammals and they get air into their lungs through blowholes. Fish have gills to get the oxygen out of the water. Being mammals, whales give birth to live babies and feed them on milk when they are young. They all have brains and a backbone and a very strong tail. They have fins at the front where your arms are but they don’t have any fins or flippers where you have legs. On their backs they have a fin called a dorsal fin which helps them to swim in a straight line. Some whales have teeth and eat fish and squid but some don’t have any teeth. These whales have hairy plates which hang down from the top of their mouths and are used like a sieve to filter tiny plants and animals out of the sea water. This is called baleen. All the whales with baleen also have two blowholes.

Mairi is a minke whale and minke whales don’t have any teeth. Minke whales feed on tiny fish and krill using the baleen plates at the top of their mouths.

Other whales which use baleen are the humpback whale (look at the picture below), the fin whale and the sei whale.

The huge blue whale also uses baleen to eat these tiny krill and in one day it eats 250 tonnes of them! The blue whale can grow up to 33 metres long and weigh 190 tonnes.

Whales with teeth include the sperm whale, which grows up to 18 metres long and can weigh up to 50 tonnes. The whale in the book “Moby Dick” was a sperm whale. These whales were hunted by whaling ships and thousands were killed every year. The hunters would strip off their blubber and boil it down to get a very valuable oil. Soon they had killed so many sperm whales that there weren’t enough whales for them to make much money hunting them. Today whales are still hunted by some countries, including minke whales like Mairi. The whales suffer a great deal when they are caught and some types of whale will soon be extinct if we don’t stop hunting them.

Whales also used to be hunted for their bones, teeth and their baleen. The bones and teeth can be carved into jewellery and ornaments. The baleen was used to make women’s corsets, tennis rackets and violin strings. Some people like to eat whale meat.

Killer whales aren’t really whales but are a type of dolphin. It is best to call them orca instead of killer whales.

To find out more about individual species click on the links below.

click here to go back to rest of species