Thursday, 23 April 2015


Different species of shark reproduce in different ways; some lay eggs and others give birth to their pups (babies) alive.

Pups are born ready to swim and hunt. They have a full set of razor-sharp teeth from ‘day one’.

A baby shark and an egg case

Young sharks grow as fast as they can because the bigger you are, the safer you are. Lots of larger animals eat baby sharks. Predators include elephant seals, giant squid, big reef fish, and other sharks.

Sharks never stop growing throughout their lives. Bigger sharks do not grow as quickly as they did when they were young. Different species of sharks grow at different rates.

7 m and 2500 kg Great White wiki

Most sharks grow faster in summer than in winter and the change in growth rate leaves a mark in their vertebrae. Age can be determined by counting these rings like counting the growth rings in a tree.

Growth rings can be seen clearly using x-rays

Some sharks may not mature and start producing young until they are 30-40 years old.

Sharks keep growing new teeth throughout their life so they never run out of sharp eating equipment. Some sharks may grow 30,000 new teeth during their lifetime.

New teeth waiting to replace old ones.
Zoology UBC

There are about 440 species of sharks in the world but we only know how long some of them can live.

Great White Shark
Up to 100 years
Tiger Shark
Longer than 12 and perhaps 30 years
Nurse Shark
About 25 years
Bull Shark
About 25 years
Spiny Dogfish
Possibly up to 100 years
Basking Shark
Longer than 20 and perhaps 50 years
Whale Shark
From 70 to 100 years
Short-finned Mako Shark
From 15 to 25 years
White-tip Reef Shark
About 30 years

Record breaking tiger shark caught as a trophy

Diving with sharks on assignment

1 comment:

  1. Nice article, very informative and easy to read for my kids. Thanks