After the movie Jaws came out, it is easy to see why people are frightened of sharks, but let’s take a look at this magnificent sea creature and see if we can learn more about it.

Currently there are approximately 400 described species of sharks; however, new species are being documented all the time. In addition, there are around 400 species of rays, a close relative of sharks.

Fossil records indicate that ancestors of modern sharks swam the seas over 400 million years ago, making them older than dinosaurs! Throughout time sharks have changed very little.

Did you know that sharks lack true bone, but rather have cartilage skeletons?

Cartilage is a type of connective tissue strong enough to give support but softer than true bone. Cartilage is found in the human ear and nose. Due to cartilage being softer than bone, it is very rare to find complete fossil remains of sharks.

So, how long does a shark live? A shark’s life span varies by species.

Some sharks like the smooth dogfish (Mustelus canis) may only live 16 years, while others such as the porbeagle shark, (Lamna nasus) may live as long as 46 years. Whale sharks (Rhincodon typus) the largest fish in the world may live over 100 years.

Here are some other shark facts:

The fastest shark is the shortfin mako (Isurus oxyrinchus). It has been recorded to reach swimming speeds of up to 20 mph (32 km/h). It can chase down some of the fastest fishes such as tuna and swordfish.

The largest shark, and also the largest fish in the ocean is the whale shark (Rhincodon typus). This massive plankton-feeder reaches lengths of over 20m (60 feet).

The smallest shark is a deepwater dogfish shark known as Etmopterus perryi. This species which is found in the Caribbean Sea is mature at under 20cm (~8 inches).

All sharks are meat-eaters with the larger sharks generally feeding on marine mammals, fish, squid, and other sharks. Bottom feeding sharks such as wobbegong, feed upon shellfish. The Whale Shark and Basking shark are filter feeders and eat tiny invertebrates such as plankton.

Sharks usually eat between 1% and 10% of their body weight weekly.

So what about those reports of brutal shark attacks?

The three sharks most dangerous to people are the Bull Shark, Tiger Shark and Great White Shark

When we read or hear about someone being attacked by a shark it has a very emotive affect on most of us, but It is important to put this issue in perspective.

In the USA in the 30 years 1970-2000 ~ 12 people died from shark attacks, in this same period ~ 1,500 people died from lighting strikes in coastal regions. These figures are only from coastal regions so as not to inflate the number of deaths from lighting strikes.

Each year worldwide there are ~ 10 deaths attributable to shark attacks compared with ~ 150 deaths worldwide caused by falling coconuts.

More people each year are killed by elephants, crocodiles, bees, and wars and many other dangers that confront us, than by sharks. 

Compare the number of deaths by shark attack with death as the result of a motor vehicle accident.

Remember there are ~10 deaths attributable to shark attacks worldwide.
USA - ~45,000 deaths by motor vehicle (pop ~250 million)
Thailand - ~ 60,000 deaths by motor vehicle (pop ~60 million)
Australia - ~ 3,000 deaths by motor vehicle (pop ~20 million)