Blue whale

This is the tympanic bone of a blue whale. It has been photographed from two different angles and is about the size of a human fist.

The tympanic bone is unique to whales. It houses the bones of their inner ear. Unlike many bones in a whale's skeleton, the tympanic bone is very dense. You can sometimes find these bones washed up on the beach where they can be mistaken for worn flints.

Here are a few facts about blue whales:

• Maximum length as adult: 110 feet (about 30 metres)
• Maximum length when born: 23 feet (about 7 metres)
• Adult diet: can eat up to four tonnes of krill a day (about 40 million krill a day)
• Newborn diet: can drink up to 50 gallons of milk a day (almost 200 litres of milk a day)
• A blue whale's eye is about the size of a tea cup
• The tongue of a blue whale can be the size of a small car
• A blue whale is equal in weight to 30 bull elephants or about 1,830 adult humans

Blue whales are a type of baleen whale. This is a sample of the baleen from a humpback whale.

Baleen whales feed by filtering small animals called krill from the water around them. They do this by taking huge mouthfuls of water into their mouths. They then squeeze the water back and through a sieve of baleen plates, trapping the krill in their mouths. Adult blue whales can take in about 70 000 litres of water in a single gulp, and eat up to 40 million individual krill a day!

These are the skeletons of two different whales on display in the Museum. The bottlenosed whale in the front of the photograph is a toothed whale. The one behind is the lesser fin whale. It is a baleen whale, like the blue whale. It feeds by filtering small animals called krill from the sea water around it.

Whales are mammals. They evolved from mammals that lived on land and, over millions of years, have adapted to life in the sea. Think about what they may need to swim - can you spot any of these adaptations in their skeletons?

This is the skull of a humpback whale. It is a baleen whale like the blue whale. They both use baleen to filter small animals called krill out of the water around them. Blue whales eat massive amounts of krill - up to four tonnes every day!

Look at the picture. The long jaw bones have been adapted to anchor the baleen plates the whale uses to filter its food. They are not like our jaws - feel around your mouth - what is this whale missing?

The blue whale is a baleen whale - it filters its food, and has no teeth. But not all whales are like this - some species have teeth they use to catch and eat fish and marine animals.

This picture shows the lower jaw of a sperm whale on display in the Museum. It is over five metres long and is covered in large peg-like teeth. Teeth like these were once carved by whalers and used to make decorative ornaments called scrimshaw.