Sharks live in every ocean and some even live in rivers and lakes. They can range from massive Whale Sharks (18 metres long and weighing 21 tonnes) to the Spined Pygmy Shark (25 cm long)

Sharks are different from other fish in many ways:

• They are the only fishes who don't have bones. Their skeletons are made of cartilage (The same kind of stuff that our nose and ears are made of).
• Sharks have no overlapping scales covering their bodies like other fish. Instead they have a very rough skin that feels like its covered with very small teeth. Dried shark skin was once used as sandpaper.
• They have no swim bladder (an air filled balloon-like organ) and will sink to the bottom if they stop swimming.
• Sharks keep growing their teeth throughout their lives. When one wears out or breaks off a new one moves up to replace it.

Sharks are predators. That means they catch their prey:

• Bottom dwelling sharks: sea urchins, clams and crabs
• Open Water sharks hunt fish, squid, other sharks, seals, birds and marine mammals
• Filter feeding sharks strain small fish, krill and plankton.