figuring out the amount of pairs

Question

A man put a pair of rabbits in a cage. During the first month of their lives the rabbits produced no offspring, but each month thereafter produced one new pair of rabbits. if each new pair thus produced reproduces in the same manner, how many pairs of rabbits will there be at the end of one year

Answer 1

This problem was first solve by the 12th Century Italian mathematician Leonardo Bonacci, know as Fibonacci.

 

The numbers are 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, ...

 

Can you determine the pattern? What is the next number?