Meet Willow! She's a chihuahua puppy. They're one of the smallest breeds of dog in the whole world. And these chaps are St Bernard puppies – some of the largest in the world! They're all gorgeous – but just compare the difference in size. Willow is only seven weeks old. But the St Bernard puppies are only five weeks old, and yet they're already four times the size of the chihuahua. Chihuahuas are actually called toy dogs. They're purposely bred to be as little as possible. St Bernards are traditionally used as mountain rescue dogs, so they're bred to be as big, strong and tough as possible. Everything about the chihuahua puppy is very little, whereas – as you'd probably expect – everything about the St Bernard is very large! Willow weighs only 500g – about the same as the can of dog food you can see on the left of the picture. The St Bernards already weigh 7kg – the equivalent of this much dog food! Quite a difference, eh? The Chihuahua's coat is sleek, and made up of very fine hairs – perfect for the heat of Mexico, where they originally come from. The St Bernards are covered in beautiful thick fur, to keep them warm in the snowy climate of Switzerland. Now compare paws! The chihuahua's paw is tiny and dainty, whilst the St Bernards is six times as big – absolutely perfect for trudging through thick snow! When Willow is fully grown he will still be very little. Here he is with Sweet Pea, his mum. Not much difference in size between them, is there? When the St Bernards are fully grown they'll be as big as Chubby Checker here. He's absolutely huge! He's the dad of all the St Bernard puppies. He weighs one hundred and sixty times as Willow – amazingly that's the same weight as Stephen! Greatly different in size, but equally Brilliant Creatures.

© The Foundation TV Productions Ltd 2002