Sharks Facts

Some shark species experience appetite suppression around the time they give birth, which may help prevent them from eating their own pups.

You are more likely to get attacked by a cow than a shark.

More than 90% of shark attack victims survive.

Sharks can detect fish heartbeats using electroreceptors called ampullae of Lorenzini that sense electrical fields as small as five billionths of a volt.

Helicoprion was a shark-like fish that lived 270 million years ago. It grew up to 4-8 meters long and had a bizarre spiral whorl of teeth on its lower jaw, unlike anything seen in modern animals.

Megalodon was the biggest shark that ever existed. It was larger than the average city bus and could bite down with a force between 10.8 and 18.2 tons - enough to crush a prehistoric whale's skull as easily as a grape.

Dolphins can rapidly heal from extreme injuries, such as shark bites, and regenerate their original body shape.

Sharks have been on the planet longer than trees.

In 2004, four lifeguards were swimming off Ocean Beach, New Zealand when a pod of seven dolphins suddenly herded them into a tight group and started circling. For 40 minutes, the dolphins swam inches from their bodies, slapping the water with their tails. When one swimmer tried to break away, two dolphins pushed him back. Only then did he spot the 9-foot great white shark circling two metres below them.

The rarest shark in the Gulf of Mexico is 5 inches long, glows in the dark, and shoots clouds of luminous fluid from tiny pockets near its fins — basically a living flashbang grenade.

Every winter there's a migration bigger than the Serengeti's - and almost nobody has heard of it. Hundreds of millions of sardines surge up South Africa's east coast in a shoal over 7km long. Dolphins herd them into bait balls near the surface. Sharks rush in from below. Cape gannets plunge at up to 86km/h and a Bryde's whale swallows the whole ball in one pass. Scientists still debate why the sardines bother.