Pregnancy period of different animals

The bar chart gives the maximum pregnancy(also called gestation) period of animals including humans.It is interesting to note that the pregnancy period of the animals increase with their size.Small rats have minimum pregnancy period whereas elephants have the largest pregancy periods.

The pregnancy period of various animals in days (click on the image to view larger size)

The data for this visualization is taken from wikipedia, here  , and visualization created with MS Excel '07.

On a related note, the gestation period of animals with the same body size vary depending upon the placenta. BBC article here.